| Clipped |
im going to try to attempt to give this 2150 sx a rebirth, it doesnt look pretty... :xeye:
if possible can someone verify the location of these components?
i picked this amp up from a friend and its been from repairman, to repairman, to technician, to god knows who....its been through alot , and it still doesnt work and i feel sorry for it.
i removed most of the caps to replace them, but i want to be sure whoever took it apart previously put the components in the right place....
how do you check the 317/337/L7815 regulators?
at first i thought the fen/p 30 rectifiers on the back of the board were bad because the legs were melted off....but after soldering the legs back together im getting identical mirror image readings for both of them...
while in the board. .632 or with the leads reversed for each diode .380...on diode check.
good lord, where do i start with this amp?
btw...the supposed demise of this amp was a 2 ohm mono load for about 30 seconds (i know the minimum is 4 ohms mono, but shouldnt it atleast be able to hold out longer without blowing?)
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| Perry Babin |
The components on top of the board are correct. I'm not sure about the two on the bottom but you can follow the center leads to the rail caps to see which goes to the positive rail caps and which goes to the negative rail caps.
Why do you suspect the regs?
What happens if you power it up? You should install at least one positive and one negative rail cap before powering it up. |
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| Clipped |
ive checked all the fets and transistors and replaced defective ones and it doesnt power up. ive checked and replaced the a56/06 and relative diodes also.
i guess im just being suspicious of the regs because , its the grey area i dont know how to check. :clown:
but let me put everything back together again and see what happens as this amp has been sitting for a while...and i may have forgotten something.
how do the readings for diodes look on the back? or do i have to pull them to get better readings? they look beat to heck, but seem to measure while 'in board'...just weird that they measure at all if i reverse the leads.
ill get back to this tomoorrow, im beat to heck right now, installed 6 speakers...made a ported box for 2-10's , hooked up 3 amps from battery...made an amprack....and wired an oem hu via loc to a pre-amp today...
and soldered everything.... :bawling: |
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| Perry Babin |
| With the amp powered up, measure and post a list of the DC voltages on the TL594 IC. Black meter lead on the ground wire of the amp. |
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| Clipped |
put the caps back in today and powered it up...
when i power it up the ammeter needle stays pegged to 100 amps...100 amps is the maximum value on the ammeter.
i took the secondary windings out of the board and powered up again...but left those two wires in that go between the primary and secondary
the ammeter goes to 10 amps, then there is a 5 second delay then the needle goes to 35 amps very slowly, and stays there.
still want me to mesure the TL494? (this one doesnt use the 594)
 |
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| Clipped |
with the secondaries legs out of the board.
the initial voltage the amp draws from my power supply/battery charger is 15.69 vdc (10 amps)
then it rest at 14.65 vdc (10 amps) for a few seconds, then it drops down to 11.43vdc...as the ammeter starts to rise to 35 amps, and stays there.
with the secondary legs out...and measured at 11.43 vdc, here are the mesurements for the TL494
1 = -0.003
2 = 0.032
3 = 0.032
4 = 0.048
5 = 1.568
6 = 3.516
7 = 0.002
8 = 11.74
9 = 0.002
10= 0.033
11= 5.022
12= 5.022
13= 11.96
14= 11.78
15= 4.91-98
16= 4.91-98
or should i measure while the secondaries are in? its drawing alot of current with them in and im afraid something is going to fry if i leave it powered up too long. |
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| Perry Babin |
Did you use the old rail caps? Is it possible that you installed one backwards or that one is shorted?
You need to use a current limiter like a 1-2 ohm high power resistor or an automotive head lamp in the B+ line to prevent excessive current draw. It's unbelievable that the amp's power supply drew 100 amps from the 12v supply without failing. It won't be able to do that too many times without failing.
If the caps aren't the problem, the current limiter will make troubleshooting easier.
The voltage on the 494 looks OK. Look up the datasheet. You have the pin numbering backwards on the top row. |
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| Whortless |
Dear Clipped,
I think your TL494 voltages are wrong. I suggest you to pull the FEP16 rectifier diodes to repair your PS instead of the complete amplifier. Check your TL494 at first or regulation lines for it. Because pin8&11 or pin9&10 should have same voltage readings. I suggest you to check, if pin9&10 is going to GND (or pin7). If so, then you can check mosfets. But, I wonder if you are reading 11V for either pin 8 or 11 one of your switching mosfet is burned. Also it can damage TL494 . I think it is easy to check the current with an ammeter by pulling up the TL494. If the circuit still needs more current higher from 1A, you should check the mosfets at first. Please, turn back with your results.
Regards |
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| Clipped |
yes i listed the pins backwards...right when i did, my ISP cut me off and have been trying to correct it for 24 hours, the whole time thinking 'what an idiot i was'...
btw pin#1 is not negative...i think its time to change the battery in this meter...
man really sorry for posting wrong stuff.
i used new rail caps i just purchased yesterday 50v 1000uf
all put in correctly, and i checked each and everyone before putting them in to make sure there would be no question about them.
but the sideways caps (old ones) act funny, sometimes they say 'disc' and sometimes they meter.
there is one problem area on this board where it has cracked across a few traces...on the other side is an A56
-------------------------------------------------------------
so should i get some current limiting resistors , put the secondaries back in and remeasure the TL494 ?
-------------------------------------------------------------
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| Clipped |
for sake of ease :D
1 = 0.003
2 = 0.032
3 = 0.032
4 = 0.048
5 = 1.568
6 = 3.516
7 = 0.002
8 = 11.74
9 = 4.91-98
10= 4.91-98
11= 11.78
12= 11.96
13= 5.022
14= 5.022
15= 0.033
16= 0.002
whortless i dont know whether you are referring to my backwards pins or the correct ordered pins, my fault. |
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| Perry Babin |
I don't know what meter you have but the 'disc' likely means that you need to discharge the capacitor or the meter is in the process of discharging the cap.
Electrolytic caps have a fault/property called dielectric absorption. It's where the cap acts a bit like a battery. Even if you short the leads together, the cap will recharge to some degree. That could be causing your problem when trying to check them.
The current limiting resistor generally makes it easier to find faults when excessive current draw is a problem. For example, you can power the amp up via the resistor and measure the voltage across the emitter resistors. If you find one channel (or even a single resistor) with abnormally high voltage across it, that will generally narrow down the area in which to look. It also allows you to meaure the voltage across other resistors and transistors with little or no chance of damaging the amp. You have to have the amp mounted in the sink so the transistors won't get hot. Generally, the only time you'll have a problem is for amps that shut down due to low voltage and with the older Orions that don't have the PWM IC in the power supply.
The voltages you posted were good enough. You don't need to take any more on the 594 for now.
Can you pull one end of each of the emitter resistors (secondary soldered back in place)? If the excessive current draw was eliminated, that would let you know that the problem was in the audio section. You could do one channel at a time. |
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| Clipped |
well i took more TL494 readings with the secondaries back in place and used five 10ohm resistors...inline with the B+
didnt read your post in time
i also changed the fen/p16 diodes although they were still good.
the amp is only seeing 8.04vdc after the resistor, the led wont light, and the ammeter doesnt budge.
1=0.001
2=0.029
3=0.029
4=0.032
5=1.562
6=3.5
7=0.01
8=6.5
9=0.423
10=0.38
11=6.515
12=6.529
13=5.019
14=5.09
15=0.029
16=0.001 |
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| Clipped |
i'll lift the emitter resistors, those big green ones eh?
NPN, the emitter is the right leg
PNP the same? |
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| Perry Babin |
The IC shuts down at 6.5-7 volts. Can you parallel a few more resistors to get the voltage up a bit more?
Did you try lifting one end of the emitter resistors? |
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| Perry Babin |
| Correct. The third leg is connected to the large resistors (for NPN and PNP). |
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| Clipped |
i took out the emitters on the side with the mono/eq button and the current draw dropped down to 20 amp (constant)
then i took out the emitters onthe other side and it still stays at 20 amps.
it initially jumps to 40 when power is first applied. then drops to 20.
---------------------------------------
i have to look for more resistors to add to my ghetto power resistor...one moment :D |
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| Perry Babin |
20 amps is probably safe for a few seconds at a time as long as the transistors are tightly clamped to the heatsink.
Can you find anything heating up?
Have you checked to see if the tabs of any of the heatsink mounted components were shorted to the sink?
Do you see anything different on yours compared to this one:
http://www.bmpt1.com/images/IMG_1383b.jpg
If it fits on the screen, your browser is likely resizing it. |
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| Clipped |
these 2 pre drivers are extremely hot....
i know these are impossible to get here...so maybe the game is over for this amp , unless there is an altenative to these parts.
i cant get the originals over here. :bawling: ....but i think i read on this board that it may be possible to use the 2N6481/91's in their place....cant remember that well.
in that pic its hard to see the color of the resistor bands.
-------------------------------------------------------------------------
what value are the gate resistors for the power supply fets, cause i got blue ones in this amp.
-------------------------------------------------------------------------
for my ghetto power resistor, think 0.8 ohms would be ok?
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| Perry Babin |
If those drivers are getting hot, they are likely defective or the outputs connected to them are defective. Pull them and check them for leakage (I'm assuming that you've already checked to see if they were shorted).
There are lots of options for those drivers. I think they are being produced by Central Semiconductor.
http://pdf1.alldatasheet.com/datash...RAL/CENU07.html
The two transistors are predrivers and drivers. You can use the original MPSU07/57 for the drivers (the ones that drive the outputs) and use something like a MPSW42 or MPSW92 for the predriver (the ones that drive the drivers).
You could use something like the 2n6488/91 but you'd have to hard wire them or twist the leads to make them fit.
This is a partial schematic of the audio section:
http://www.bmpt1.com/images/orion01.swf
The two TO-92 transistors in place of the u07/57 were used for testing. The amp was abandoned so I never finished it.
The missing a06 is for over-current protection if I'm not mistaken.
The two missing transistors in your amp are the muting transistors. They should be 2N5639s.
The gate resistors are 10 ohms. |
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| Clipped |
ok pulled out those hot ones, they were bad...pulled out the rest of them and found one more bad 07.
put the emitter resistors on the outputs back in place and powered it up...current draw dropped down to normal, or so i think, my ammeter starts at 10 and thats where it is sitting at.
the pre-drivers in this amp are currently the A56/A06...are these the originals?
i think i may choose to run the 2ne6488/91 for the drivers with the legs bent around to accomodate EBC opposed to BCE.
would you know what differences i can expect if i use the 2ne's as drivers? will there be severe performance differences, excess heat build up, gain differences, pros / cons....to be associated?
the mpsu is listed at 2 watts, but the 2ne's are listed around 75 watts....or will they run cooler and possibly better than the mpsu's....? or will they drive the outputs too hard?
will they last for the life of the amp? those replacement parts are really hard to find here, i can usually find one side of the complimentary pair, but then i get left high and dry for the other side.
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| Clipped |
just measured the outputs ,ps fets and fen/p16 diodes
-------------------------------
outputs/emitter resistors
37 vdc for positive rail
-37 vdc for negative rail
all measure the same
-------------------------------
ps fets/gate resistors
1.79 vdc
all measure the same
-----------------------------
for the fen/p16 diodes
the negative diode is at 0.002 for the middle leg and 9.9 for both outer legs.
positive diode is at 19.9 middle leg, and 9.9 for both outer legs
is this normal?
:confused:
ps...make sure you read my other post before this one in case you missed it... :D |
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| Perry Babin |
Using the 2n transistors should make no difference in performance.
They will not drive the outputs any harder.
They will run slightly cooler than the U07/57 because they have ore surface area. If you want it to look better, mount them under the board like the large rectifiers. Use short pieces of wire to connect them to the board. If you're lucky, you may be able to get the collector and base legs to go directly into the board. Then you'd only have to hard wire the emitter.
They will last as long as or longer than the U07/57s.
Those voltages look OK except for the negative rectifier. I would expect it to have -20v (approximately) on the center leg.
To determine if you ammeter is correct, connect the power resistor in series with the main power wire and measure the voltage across it. Using Ohm's law, you can determine the current flow.
If you find that the amp is actually drawing 10 amps of current, it could be due to a short in the negative rectifier circuit. If the ammeter is not accurate and there is no excessive current draw, the rectifier may be open. |
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| Clipped |
alright im gonna go for it and put in the 2NE's....hope it works out:xeye:
about the negative rectifier, i think i measured it wrong...i put the black lead on the B- and the red lead on the middle leg.
so i tried putting the red lead on B+ and put the black lead on the middle lead...14 vdc .....is this the right way to measure it?
just wondering, if you have a transistor that checks out ok, but is 10 years old, will the output still be the same as it were new?
because these 2NE's i plan on using are oem orion from other amps i pulled them from...my other alternative are the BD911/912's....which i have been using in place of the 2NE's.
well , i'll let you know how the modification goes...and Thanx!!! |
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| Perry Babin |
Use the secondary center tap or the RCA shield ground on the amp for the reference point (black meter lead). The red lead would go to the center leg of the negative rectifier. The voltage should be approximately the same as on the positive rectifier but with the opposite polarity.
10 year old transistors may still meet spec in some ways (Hfe, threshold voltage, leakage...) but if driven hard, they may be more likely to fail. I'd strongly suggest using new transistors. Although I don't have any experience with them, the BD911/912 should work as well as the 2N6488/91.
If your used transistors were in parallel with a transistor that failed, I'd suggest against using them for any repair. If one transistor of the set was subjected to a load that destroyed it, the others may be weakened or otherwise damaged. Transistors are cheap. If one fails, it can take out many more. You should always use new parts. |
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| Clipped |
im stumped on the negative rectifier, i checked the fen/p16 as well as the fen/p30 underneath ... check the a0/56 drive transistors as well... all were good.
how is it that the output transistors are still getting a negative rail voltage as well as a positive rail? if that rectifier isnt giving a
-20vdc voltage reading?
TL494 defective?
:( |
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| Perry Babin |
Now you've done it! You made me learn something new.
The two FEx16 rectifiers are used to generate a 20 volt supply that's used to generate a secondary voltage source for the power supply drive circuit. This is similar to the circuit in the punch amps but much more complex.
I believe they use this type of circuit to insure that the drive voltage never drops too low even if the B+ voltage drops.
The center leg of the negative rectifier is grounded. The outer legs are connected to the extra, isolated winding of the power transformer (near the negative rectifier).
In operation, the negative rectifier simply prevents the voltage on the winding from going significantly below ground (sort of the same function as in a voltage doubler circuit -- the type using diodes and capacitors).
The center leg of the negative rectifier should be at 0v.
The large rectifiers under the board supply the rail voltage.
The 494 is OK. |
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| Clipped |
***Clipped smacks himself on forehead*** :bigeyes:
hey man, you had me scared with that first sentence... :D
i was wondering what those wires were for by the neg rectifier, i thought they were just there to confuse me .
a power supply for the power supply.... sure dont make em like they use to...
speaking of 'punch' i have an oldschool punch 75 with a ps problem, i turned those pots and poooffffff.... i smell another post coming on . :clown:
will start bending 2NE legs tomorrow... :) :) :) |
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| Whortless |
Dear Clipped,
I have not notticed the pin order like Perry Barbin. All my suggestions based on normal pin numbers. But, I saw you are measuring true things on TL494 and it is not defective. I want to get you repairing PS(power supply) at first. So, I again suggest you to remove the FEP/N16 diodes. Then make sure your amp(PS) does not exceeds 1 or 2 amps(20 amps is still much more).But, I am feeling, you have a defective part on your circuit's (amp section) negative rail. Because you should read same voltage readings for positive and negative rails. The defective part probably one of output transistor. I do not know your circuit. All my suggestions based on experience on repairing/building car amps.(because all of them have similar circuits)
Regards |
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| Clipped |
| Hi, Whortless....where is kocaeli? |
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| Clipped |
im a little confused as how to check the ammeter...do i measure the voltage with the black lead on B- and the red lead on B+ after the resistor?
or do i measure the before/after voltage after passing through the resistor? :confused: |
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| Perry Babin |
Connect the resistor in series with the B+ line (one end to the DC power supply and the other end to the amp's B+ wire).
Meter set to DC volts.
One lead on each end of the resistor.
Apply remote voltage to power up the amp.
Read the DC voltage across the resistor.
V=I*R rearanged to I=V/R
V = voltage across the resistor.
R is the resistors value (ohms).
I = current passing through the resistor into the amp.
Compare the ammeter reading to the calculated current. |
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| Clipped |
0.722 ? i use this number? i wasnt so sure because it looks so low.
so I=V/R
would be
I=0.722/0.8
I= 0.9025
seriously , it couldnt be that low coud it? well assuming the signal drivers arent in place...maybe?
this is with voltage at approx 13.1 vdc measured before the resistor |
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| Clipped |
:D :D :D |
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| Perry Babin |
If the resistor is 0.8 ohms, 0.9 amps is correct.
Even after you replace the drivers and output transistors (if they need to be replaced), the current draw shouldn't be much higher.
Very few amplifiers in good working order draw more than 2 amps of current at idle. |
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| Whortless |
Hi Clipped,
Kocaeli is a city from Turkey. Perry Barbin more experienced on your amp and his suggestions are correct. Any way, most of car amplifiers could draw only a few amps while working without sound input/output. For eg. I am using a 12V 1A (can give 5A peak)DC power supply to test if an amp is working or not. If it is not working with this power then usually i am firstly checking the power supply section and then the output transistors. This is a safety way not to blow the pcb traces. When all the repair finish, I am testing it with 14.4V 40A SMPS which is made by me.
Kind regards |
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| Clipped |
well.....put the 2NE's in .... and it went back to maxing out the ammeter at 100 amps again.... i did this after , putting the capacitor inline, becuse i thought something was fishy :bawling: ........:( ............ :smash: .........:mad:
the orange channel is putting out -7 vdc
the yellow channel is putting out .035 to .045vac
checked the rest of the Ao6/A56....all were good but changed them anyway...
im gonna go get drunk now... :whazzat:
:bawling: |
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| Clipped |
meant resistor inline
man, sure wish i wouldve measured the outputs earlier :dead: |
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| Perry Babin |
With the series resistor in line, your meter set to DC volts and the amp on, measure the voltage across EACH emitter resistor in the channel producing DC.
Do they all have approximately the same voltage?
What's the voltage across them (assuming they're all the same)?
Are you 100% sure you have the replacements wired correctly AND have the replacements in the correct locations (NPN/PNP)?
Have you cleaned the flux from the solder connections so you could see if there are any solder bridges?
If not, have you checked for solder bridges or shorted components with your ohm meter?
Have you measured the base-emitter voltage for all of the output transistors?
Compare the B-E voltage of the good channel to the bad channel.
Post the B-E voltages for the NPN and PNP output transistors of both channels (4 voltages) if the all of the NPNs and all of the PNPs in each channel match (±10%). |
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| Clipped |
orange channel
emitter= 7.38 and -7.34
base = 6.99 and -6.85
yellow channel
emitter = 7.47 and -7.41
base = 7.46 and -7.40
this is how the drivers were oriented when i got the amp:
im gonna pull out a pair of 2nes at a time, to see if i can find a problem pair. |
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| Clipped |
when i take this pair out, the emitter goes to +/-37 volts as well as the base.
after taking out that pair the orange channel is still getting
-6.3vdc on the speaker outputs
the ammeter doesnt jump up after taking that pair out.
and the power LED doesnt come on.
looking at this pic, i cant really seem to determine the orientation of the orange channel drivers , but it looks like the adjacent pair is backwards. (cant tell)
 :( |
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| Perry Babin |
For future reference, when you measure 'across' anything, place one lead on each of the terminals and give one value. Here, you would have placed one lead on the emitter and the other lead on the base. Doing it this way will reduce errors.
In the orange channel, you can see that the low side transistors are being biased on (barely but enough to allow them to conduct). This would cause a negative DC output. The high side outputs are probably on also (although 0.4v isn't generally enough to make BJTs conduct). If both are on, the amp would certainly draw excessive current.
The attached photo shows the drivers from a working amplifier. The U07/57 is hidden but you can use the code at the top of the transistor to see which is the 07 and which is the 57.
Check the drivers before reusing them.
If you have MPSA06s and MPSA56s, you may want to use them to get the amp playing and then install the larger drivers after you've found all of the problems. |
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| Clipped |
well...it looks like someone who worked on it before me put those circled drivers in backwards.
i'll get back when i get some AO6/56.
this amp is driving me nuts... |
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| Perry Babin |
If you look at the pads for the drivers, you'll see one is square. That is almost always pin 1.
The only exception that I know of is for the jfets (in the muting circuit) in Orion amplifiers. |
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| Clipped |
yeah i was supicious of it from the beginning, but i heard it play with the drivers backwards so didnt give it much consideration.
i guess now i know why it blew....oh btw after rearranging them, that high current (100 amp )draw stopped, now its only around 12 amps.
a couple sets of those 2ne's get hotter than the others....i hope the AO6/56 hold up for testing..since the 2ne's themselves are heating up.
that lone 2NE5639 was also backwards. |
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| Perry Babin |
That's a Jfet. They're installed with pin 3 in the square pad.
If the TO-220 case transistors are getting hot, the smaller transistors don't have much of a chance.
Have you rechecked all of the output transistors? |
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| Clipped |
asking someone to check all the outputs on an old school orion amp...is like asking them to pull a tooth, all 20 of them... :dead:
i know i can just take off the base and emitter legs..but, but, but
but i have to do it...
i remember the jfet situation from a previous 225 hcca you helped me fix, with a defective muting cicuit.
time to start pulling... |
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| Perry Babin |
Use a hot iron and add extra solder to the pads. Lay the iron across all 3 legs and wipe the transistors off of the board. It takes about 3-4 seconds each with a good iron.
All you have to check are the ones in the channel where the drivers were installed backwards.
If you use the limiting resistor and measure the voltage across each of the emitter resistors, it may lead you to the problem (without removing the transistors). |
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| Clipped |
well checked the transistors, all were good
pulled the 2ne's im using as drivers (taken out of board) and the vdc on the speaker outputs went away.
the 2ne's were still good.
checked all the resistors and diodes on the orange side, all were good.
must be something inline before the 2ne's and a56/06 pre-drivers
is there any chance the opamps could be suspect?
i know im getting close, but when it comes to signal paths i just get lost. |
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| Perry Babin |
There are 4 diodes in series. They are pulled toward the rails by two 18.2k ohm resistors. If you measure across the 4 diodes (where they connect to the resistors), you should read ~2v DC. If it's more than ~3v, that could be a problem. The predrivers should be removed for this. The outputs and the drivers can remain.
If you install only the outputs (no drivers or predrivers), do you have any DC offset or current draw?
Leaving the outputs in... If you install the drivers (the transistors that connect to the base of the outputs through ~2.7 ohm resistors), do you have any DC or excessive current draw?
Are you sure the outputs are in the correct locations?
The op-amp could cause DC offset but not excessive current draw. Excessive current draw is generally due to having opposing transistors 'on' at the same time. |
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| Clipped |
| quote: | Originally posted by Perry Babin
There are 4 diodes in series. They are pulled toward the rails by two 18.2k ohm resistors. If you measure across the 4 diodes (where they connect to the resistors), you should read ~2v DC. If it's more than ~3v, that could be a problem. The predrivers should be removed for this. The outputs and the drivers can remain.
------------------- getting 1.92vdc
If you install only the outputs (no drivers or predrivers), do you have any DC offset or current draw?
------------------- drawing 1 amp....orange channel has
-0.049vdc red l ead on orange wire/black lead on orange black stripe........yellow channel 0.0vdc
Leaving the outputs in... If you install the drivers (the transistors that connect to the base of the outputs through ~2.7 ohm resistors), do you have any DC or excessive current draw?
----------------- current draw is relatively the same....but get -10.64vdc on orange channel...yellow gets 0.045vdc
Are you sure the outputs are in the correct locations?
-----------------
The op-amp could cause DC offset but not excessive current draw. Excessive current draw is generally due to having opposing transistors 'on' at the same time. |
---------------- the excessive current problem is gone, ever since i flipped those two backwards drivers
if the guy before me put the transistors in wrong, im going to track him down and............. :cool:
as of right now the A56/O6 are still out of the board |
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| Perry Babin |
If the yellow channel isn't causing problems, you can leave all of the parts in it.
The drivers and predrivers are (were) the U07s and U57s.
You can identify the drivers by measuring the resistance between their collectors and the collectors of the outputs. All are directly connected.
The base of the predrivers is directly connected to the point where the 4 series diodes connect to the resistors. One predriver connects to one end of the diodes and the other predriver connects to the other end of the diodes.
Using the information above, are you sure you installed only the drivers and no predrivers? |
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| Clipped |
ohhh, ok now i get it, the 057/07 drive another set of 057/07
i thought the a56/06 in my picture in the previous page were the pre drivers...
what are those a56/06 for? because i took them out. please look at previous page pic. |
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| Clipped |
pulled the pre drivers for orange channel and got the same number...i think i measured the wrong legs previously and got 1.92....but still the same if i measure the same legs
for the two legs (correct legs)top and bottom by the tantulums, this time im getting 2.5
no excess current draw...no dc on speaker outputs
readings for the yellow channel are the same... |
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| Clipped |
may have found the problem, the ne5534 isnt getting vcc+ only vcc-
now i just have to figure out why... :( |
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| Perry Babin |
The NE5534 has the positive regulated input on pin 7, not pin 8.
Measure the voltage across the two center legs of the predrivers. Is that 2.5v?
For the orange channel only, with no power applied to the amp, what is the resistance from the first leg of the predrivers to the RCA shield ground (two resistance values)?
What's the resistance from the third leg of the predrivers to the positive and negative rails (4 resistance values). The emitter resistors go to the rails so you can use them as the rail connection.
If you'd like, you can compare the readings above to those in the other channel but they should be the same. |
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| Clipped |
The NE5534 has the positive regulated input on pin 7, not pin 8.
----- yep, downloaded the data sheet for a philips device, voltage is 0.000 vdc
Measure the voltage across the two center legs of the predrivers. Is that 2.5v?
----- yes sir, getting 2.5 vdc (put A56/06 in because i pulled a via)
For the orange channel only, with no power applied to the amp, what is the resistance from the first leg of the predrivers to the RCA shield ground (two resistance values)?
-----140.5 & 140.8 ohms
What's the resistance from the third leg of the predrivers to the positive and negative rails (4 resistance values). The emitter resistors go to the rails so you can use them as the rail connection.
A56
================
red on third leg
negative rail= 29.4m ohm
positive rail = -1.61m ohm noise in PS
================
black on third leg
negative rail= -4.3m ohm
positive rail= OL no reading and same noise
-------------------------------------------------------------------
-A06
================
red on third leg
negative rail= OL and same noise in PS
positive rail = -1.4 to -4.4m ohm (this guy changes everytime i measure it)
=================
black on third leg
negative rail= -1.61m ohm and same noise in PS
positive rail= 206 ohm
=================
sorry , didnt know where i should put each lead.
im starting to get the feeling this amp is pretty screwed up...in more ways than one...:dodgy: |
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| Perry Babin |
The amp may have a few problems but it's not badly damaged. We just have to narrow the problem down and it takes a bit of time.
If the amp was off when you measured the resistance between the rail and the third leg of the predrivers, you have 2 open/defective resistors. You should read 75-100 ohms between the collector (third leg) of the predrivers and one of the rails.
This is how they're connected:
NPN predriver collector >> 75-100 ohm resistor >> emitter resistor of 6491
PNP predriver collector >> 75-100 ohm resistor >> emitter resistor of 6488
Check the resistors and continuity between the resistors and transistors.
Also check for continuity between the collector of the predrivers and the base of the drivers.
The reg should be easy to troubleshoot. Confirm that you have rail input on pin 3 and output on pin 2 of the LM317. See the attached photo for the circuit path to the 5534. Both 5534s are powered by the same reg. |
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| Clipped |
those pre drivers were measured with the power on. :whazzat:
here they are again with power off: ;)
----------------------------------------
A56
----------------------------------------
red on third leg
negative rail= 100 ohm
positive rail = -1.61m ohm
================
black on third leg
negative rail= 100 ohm
positive rail= 2.38 ohm
----------------------------------------
A06
---------------------------------------
red on third leg
negative rail= 2.4m ohm
positive rail = 100 ohm
=================
black on third leg
negative rail= -1.5m ohm
positive rail= 100 ohm
=================
are they good?
which lead goes where? this is kinda confusing...
------------------------------------------------------------------------
This is how they're connected:
NPN predriver collector >> 75-100 ohm resistor >> emitter resistor of 6491
PNP predriver collector >> 75-100 ohm resistor >> emitter resistor of 6488
Check the resistors and continuity between the resistors and transistors.
>>>>>>>> you lost me here, i thought the pre drivers go to
the drivers first? im trying to follow the collector of
the pre driver, but the first thing the a56 hits is the
base of the driver.....the other pre driver hits a
mylar cap, then hits the base of the other driver.
i'd really appreciate a pic of this one, its throwin
me off bad...
------------------------------------------------------------------------
Also check for continuity between the collector of the predrivers and the base of the drivers.
>>>>>>>> 0.2 ohm for both
------------------------------------------------------------------------
The reg should be easy to troubleshoot. Confirm that you have rail input on pin 3 and output on pin 2 of the LM317. See the attached photo for the circuit path to the 5534. Both 5534s are powered by the same reg.
>>>>>>>> pin 3= 25 vdc
pin 2= 14 vdc
black lead on rca shield ground
-------------------------------------------------------------------------
question regarding the missing 2ne5369 muting transistors, do the holes need to be filled in to take proper measurements? |
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| Perry Babin |
In general, you never use you meter on diode check or ohms when voltage is present in the circuit. The voltage in the circuit will skew the results.
The resistors look OK.
The reg looks OK. The resistor between the diode and the IC is likely open.
The muting transistors don't need to be in the circuit.
Did you see this? It was posted earlier.
http://www.bmpt1.com/images/orion01.swf
The next step is to reinstall the predrivers. Be sure to get them in the correct locations (NPN and PNP in the correct locations).
Before you power it up, solder a small jumper wire across two of the biasing diodes (the 4 diodes in series). Solder a jumper across each of the two center diodes. I want to be sure that the predrivers are not biased on.
If the predrivers are out of the other channel, leave them out.
Power up the amp. Does it draw excessive current? |
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| Clipped |
like this? i just want to make sure, so i can stop being redundant.
ABCDE?
 |
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| Clipped |
| quote: | Originally posted by Perry Babin
The reg looks OK. The resistor between the diode and the IC is likely open.
>>>>>>>>>>that resistor is reading around 3 ohms, its ok
The muting transistors don't need to be in the circuit.
>>>>>>>>>>but do the holes have to be filled in?
Did you see this? It was posted earlier.
http://www.bmpt1.com/images/orion01.swf
The next step is to reinstall the predrivers. Be sure to get them in the correct locations (NPN and PNP in the correct locations).
Before you power it up, solder a small jumper wire across two of the biasing diodes (the 4 diodes in series). Solder a jumper across each of the two center diodes. I want to be sure that the predrivers are not biased on.
If the predrivers are out of the other channel, leave them out.
Power up the amp. Does it draw excessive current?
>>>>>>>>>>the excessive current draw problem stopped a while back when we figured out someone put the drivers on the orange side backwards....
jumping the across the diodes like you told me, the current draw is not excessive and everything is still acting the same, still getting 10 vdc out of the orange channel...
before the next step, do i have to remove the jumpers across the diodes?
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| Perry Babin |
Until you restore the regulated voltage, you're not going to have clean audio and are likely to have DC offset.
Looking at the photo I attached in post #57, where do you lose the regulated voltage?
I didn't realize that the current draw was back to ~1 amp. I thought it was at 12 amps still. You can remove the jumpers if the current draw remains less than 2 amps.
Unless there is a pulled via, the muting transistors do not need to be in the circuit. |
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| Clipped |
just to double check the current draw, could you tell me how to figure it out correctly?
measuring across the power resistor, i can figure it out, but with it out..im not sure how to do it.
i just rely on the ammeter on the charger without the resistor in place, but it is 10 amps minimum on the needle, and im pretty sure it is not accurate.
i have a clamp meter but i dont trust it. |
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| Perry Babin |
If you have the series resistor in the B+ line, the current draw is:
voltage across the resistor divided by the resistor value
If you have 1 volt across a 0.8 ohm resistor, the current draw is 1.25 amps. |
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| Clipped |
i may have found something...
the 3 ohm resistor to the immediate right of the 5534 in the orange channel, is bad, .....there is also a orange teardropped shape mylar cap that doesnt measure...they are both connected together.
this mylar cap is tied into the ground plane, with voltage coming in through the other leg via the 3 ohm resistor.
i replaced the 3 ohm resistor with a few other resistors in series to get 3 ohms....powered it up and the current draw spiked up big time and the resistor got really hot..and the ps also started to make a wizzing sound.
...was it shorting that caused this and possibly the cause of my/our headache??
i cant see under the 5534 but im pretty sure it goes to pin 7, the v+ ....pin 7 used to read 0.000vdc <<<would this mean a direct short? since there is no +/- polarity?
now its at like 0.6 vdc....and the dc output on the speaker wires dropped down to 6 vdc from 10vdc
so you think its possible that these two components is what is causing the problem?
theres no value on the orange teardrop mylar, do you know the value? i have to run out and buy one tommorrow, is there a higher temperature alternative?
it was hell to get out of the board, i had to remove the surrounding caps so it wouldnt draw the heat away.
i think this is finally it !!!! :D :D :D
------------------------------------------
i wasnt sure of the current draw, because with it in the needle stays right below 10 amps but with it out, it rides just on 10amps..will buy a more sensitive ammeter.
ps...the regulated voltage in the picture in post 57 is constant throughout. |
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| Perry Babin |
The teardrop capacitors are tantalum capacitors. They are known to short.
The amp should work without the cap in place. If you have an electrolytic of approximately the same value, you can use it as a temporary replacement.
If the tantalum cap was connected between the regulated B+ and ground. It would have caused the 2.7 ohm resistor to open. You can use your ohm meter to confirm that the tantalum was connected to pin 7.
These could both have caused the DC offset but I wouldn't expect them to cause excessive current draw. The regulator is limited to ~1 amp. Even if it was passing 1 amp, I wouldn't expect it to cause more than ~4-5 amps of draw from the power supply.
With the tantalum capacitor removed, does the amp draw excessive current? If so, how much? |
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| Clipped |
8.65vdc/1.1 ohm =7.86 amps
(i changed the resistor to bigger higher wattage 1.1 ohm)
i just checked the speaker output and it is now .045vdc
pin 7 on the 5534 is now also getting 13 volts !!! :)
the fets in the ps are pretty chewed up, one day i gave power to it out of the sink so i could feel the heat individually , and there are some getting hotter than others, one broke off too. |
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| Clipped |
i cant be sure of the value of the cap, you know the value? thers no specs on it.
its not one of the disc shaped ones its a teardrop, i thought it was a mylar....oh well...learn somethig new. |
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| Perry Babin |
The current draw is still excessive.
Were the jumpers in place when you measured the voltage across the 1.1 ohm resistor?
If not, replace them and check the current draw again. If they were in place, jump the other two diodes and recheck the current draw.
The cap is a 2.2uf. You'll need one rated for at least 16v. I'd suggest a 25v if you're going to replace it with another tantalum. |
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| internecine |
Sorry to go off topic, but i have a question for you Clipped.
I came across a post of yours stating that you own a pioneer cd-1000 crossover. do you happen to still have this item? im curious because i have this same crossover and am having problems with it. I cant seem to get decent out put from it without clipping the **** out of it. |
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| Clipped |
well, had a little mishap, tried playing music through the amp and now theres no ac coming through to the secondaries, and started pulling crazy current afterwards...
checked the fets 3 are dead...will fix before moving on, i really have to do something about those diodes underneath.
internecine, i stil have that crossover, but its not working, the output for that unit is only 500milivolts. |
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| Clipped |
any amp will work with it, maybe just not to its full potential...
a line driver would do wonders for it...its a good crossover.
it actually cuts the frequencies where it says it will.
what kind of headunit you got?
audiocontrol has a 6 channel linedriver called the 'Matrix' which would be perfect for it... |
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| internecine |
| are there only certain amps that will work with this amount of out put? would a line driver after the crossover help? |
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| internecine |
im using my stock HU, the stock HU has pre outs which i run to the cd-1000.
im just about to get rid of the thing because i cant get any sort of devent volume out of it. although i really want to keep it, like you said, its an amazing piece of equipment.
when i run the RCAs straight to the amp the volume level is great, even with the gains at the minimum. but when run through the CD-1000 i have to crank the gains on the amp. even then i dont get much output.
ive played with the input and output levels on the CD-1000 and i get nothing usable. Ive tried a audiocontrol EQL with line driver before the CD-1000 and that didnt help anything. So i guess i could try the EQL after the CD-1000, if that works, then i could get a line driver for each channel, but that seems silly, i would need a 14 channel line driver for this thing if i used it for 3-way front, rear and sub.
btw, thanks for helping |
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| Clipped |
| yeah id get rid of it, i think the solder is getting down to past its usefull life...i cracked mine open and the solder looked stale and dehydrated, really strange....it is a pretty old piece. |
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| Clipped |
| quote: | Originally posted by Perry Babin
The current draw is still excessive.
Were the jumpers in place when you measured the voltage across the 1.1 ohm resistor?
If not, replace them and check the current draw again. If they were in place, jump the other two diodes and recheck the current draw.
The cap is a 2.2uf. You'll need one rated for at least 16v. I'd suggest a 25v if you're going to replace it with another tantalum. |
i changed those zeners out with fresh ones, replaced the tantulum with same value, and put in a 1/2 watt 3 ohm resistor, in place of the bad one.
the current is down to normal now after changing those fets.
with resistor in place:
1.25vdc/ 1.1ohm = 1.13 amps
(with the resistor removed it also looks normal now)
it shut down because i tested it without the resistor with music.
(i'll admit it) prior to changing them the current was excessive.
-------------------------------------------------------------------
the sound was scratchy so i changed the pot, but too 100k, since this was all i had, other than 250k and 10k...will i be losing volume because of this 100k?
right now i have 3 different fets in the ps ..
15= smp60n06
2=IRFZ44n
1=ssp60n06
i will change them once this thing is debugged.
one strange thing, the fets on the yellow side run cooler than the other bank.
anything i should check out before i take the resistor off the B+ and test it full tilt?
im listening to it right now with power resistor in place bridged mono @4 ohms...for around 40 minutes now. |
|
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| Clipped |
| quote: | Originally posted by internecine
im using my stock HU, the stock HU has pre outs which i run to the cd-1000.
im just about to get rid of the thing because i cant get any sort of devent volume out of it. although i really want to keep it, like you said, its an amazing piece of equipment.
when i run the RCAs straight to the amp the volume level is great, even with the gains at the minimum. but when run through the CD-1000 i have to crank the gains on the amp. even then i dont get much output.
ive played with the input and output levels on the CD-1000 and i get nothing usable. Ive tried a audiocontrol EQL with line driver before the CD-1000 and that didnt help anything. So i guess i could try the EQL after the CD-1000, if that works, then i could get a line driver for each channel, but that seems silly, i would need a 14 channel line driver for this thing if i used it for 3-way front, rear and sub.
btw, thanks for helping |
you tried turning the gains at the top by the clipping lights right? |
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| internecine |
yea, i turn those up 1/4 way, any more than that and the clipping light starts flashing and the speakers start distorting
i want this thing to work so badly. but i dont think thats going to happen |
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| Clipped |
when i opened mine up, most of the capacitors were bad and leaking, especially the ones in the power supply and the electrolyte was starting to eat through the board.
on the outputs there are A56/06 pairs for each channel used for output...by the rca jacks, its a long shot but maybe theyre starting to go...i found a couple on this one that had cracked solder joints.
taking this thing apart is no fun man...they used really cheap solder on these guys, get rid of it. |
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| Clipped |
| quote: | Originally posted by Clipped
i changed those zeners out with fresh ones, replaced the tantulum with same value, and put in a 1/2 watt 3 ohm resistor, in place of the bad one.
the current is down to normal now after changing those fets.
with resistor in place:
1.25vdc/ 1.1ohm = 1.13 amps
(with the resistor removed it also looks normal now)
it shut down because i tested it without the resistor with music.
(i'll admit it) prior to changing them the current was excessive.
-------------------------------------------------------------------
the sound was scratchy so i changed the pot, but too 100k, since this was all i had, other than 250k and 10k...will i be losing volume because of this 100k?
right now i have 3 different fets in the ps ..
15= smp60n06
2=IRFZ44n
1=ssp60n06
i will change them once this thing is debugged.
one strange thing, the fets on the yellow side run cooler than the other bank.
anything i should check out before i take the resistor off the B+ and test it full tilt?
im listening to it right now with power resistor in place bridged mono @4 ohms...for around 40 minutes now. |
so , i guess everything is good to go? :dodgy:
im going to change all the ps fets today, so i'll let you know if there's an explosion. |
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| Perry Babin |
The pot is in the feedback circuit so higher resistance will increase the gain.
Are all of the FETs new (never in the amp when the power supply failed)?
If all of the SMP60N06s are new, I'd suggest running 7+7. If they get hotter on one side than the other, check the A06/A56 drivers in the PS. Are the gate and drain waveforms the same on both banks?
Check the waveforms at ~12.5 v and at ~13.8v (or wherever the regulation drops the gate drive voltage).
Have you checked EACH of the gate resistors INDIVIDUALLY?
What are you using for drivers in the audio section? |
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| Clipped |
just got some new pots today, will be putting back in the 50k
--------------------------
the fets that were in the ps, when it failed were, smp60n06 from various amps i pulled them from...but all metered correctly.
i just went and bought some IRFZ48n fets to put in, these were the closest ones i could find around here.
--------------------------
i was suspecting the a56/06 like you said , i metered them in board but havent had time to pull them out and check yet.
-------------------------
cant check the waveform, no scope. :(
--------------------------
ive checked the gate resistors but didnt pull the legs...im going to go ahead and change them out when i put in the new fets.
--------------------------
for the drivers and pre drivers...im using mangled 2NE6488/91...with the legs bent around.
---------------------------------------------------
for the actual output,i just bought some BD909/910 (80volt)im going to replace the 6488/91 with....i usually use BD911/912 (100volt)so it runs cooler, but i believe that the 909/910 are stronger with the given rail voltage, or i may be wrong....we'll see.
they are both 90 watt devices opposed to the 2n6488/91 which are 75 watts. all three have the same current rating.
working on these orion amps are hell, so many transistors/fets/resistors... :bawling: |
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| Clipped |
Im not sure if the other tech put the A56/06 drivers in the right place...could you take a look at this pic and verify?
thanx
 |
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| Perry Babin |
The driver are correct.
Check the resistors between the collector of the A56s and ground. |
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| Clipped |
jeez....man, what the ...oh gawdddd...
there is no resistor there for the a56 on the yellow side...
the one on the orange side is 10 ohm....yellow side the same value?
i must find the previous tech and smack him upside the head, just once.... :mad:
man, i just want to say thank you for all your help, this amp has been disected ,mutilated and dismembered...theres no way i couldve gotten this thing working without your help.
btw, theres two filled in vias by the screw hole next to the last fet on the yellow side, it doesnt look like anything is supposed to go there...but just incase....is there supposed to be? |
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| Perry Babin |
The resistors are the same on both sides.
Those vias are empty (no electronic components).
After you've got it working, you should go back and clean all of the flux from the solder conections with acetone and a toothbrush. If you haven't been doing this, it has to be a mess from all the times you had to pull the various parts.
Be sure to discharge the B+ caps (by shorting the power/ground wires together) before cleaning the board. Clean the board outdoors. Acetone is extremely flammable. |
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| Clipped |
well i dont think i was meant to get this amp working....after i put that 10 ohm resistor in ,the new fets, new a56/06 drivers and new gate resistors...everything went downhill from there.
i powered it up through the resistor and output was way distorted and the volume level dropped to about 20%
shut it down to check things out and the next time i turned it on, a diode blew :hot: (the one on the orange side to the right side of the vertical standing 6488)
changed that diode, as well as the the teardrop tantulums in the ps.....changed the vertical 6488 and replaced the L7815 reg.
now it wont even power up... |
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| Perry Babin |
Is it possible that you have a solder bridge between the terminals of one of the components you replaced?
Double-check with your ohm meter to be sure that there are no shorted connections. |
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| Clipped |
ive checked and double checked im not even getting any voltage at pins 8,11, 12 in the tl494.
legs 4 and 5 on the mct2 dont have any voltage either. ...but leg 1 gets 1.23 vdc
im also trying to trace back where the thermostat is getting power from, but having a hard time following it back.
but im finding something weird though... there are two diodes that appear to be backwards, i dont know if this is the way its supposed to be or not because when i look up pics on the web, they are the opposite of the orientation of this amp, maybe people trying to fix this amp put them in backwards...its questionable.
this is how they are:
but when i reverse them and put them in the correct '''traditional position'''.... the one on the bottom burns up.....if i leave them the way they are nothing happens.....it stays
the diode on the bottom did burn up in this position before i changed it...but after replacing it in the same position, it has stayed.
the amp played the other day i was testing it, all day...i put a heat sink on my powerline resistor in case your wondering. |
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| Perry Babin |
See attached photo for diode orientation.
The thermostat receives power from the emitter of the A06. |
|
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| Clipped |
is that a 7915 in that pic, because theres a 7815 in this one.
the diodes in this amp are facing in the opposite direction.
***scratches head*** |
|
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| Perry Babin |
No. It's a 7815.
The striped end of the diode goes to the square pad. |
|
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| Clipped |
when i put the diodes in the correct orientation the bottom one burns up, tried 4003 4004 4005 just incase the other guy put in the wrong value, but it still burns and smokes...
this amp is one messed up piece of equipment. |
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| Perry Babin |
The bottom diode feeds B+ to the MPSA06.
If the diode is burning up, I'd think that there would be a short circuit to ground somewhere.
The MPSA06 can't handle as much current as the diode so I'd expect it to be damaged also. |
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| Clipped |
the area with the dides and 7815 looks pretty messy, im gonna scrape off the solder mask to look for cracks in the board and clean things up to get a better look.
in this area it looks kinda charred with a couple fiberglass strands starting to poke through.
legs 4,5,6 of the mct2 measure ok, anyway to measure legs 1&2?
should it be open or should i get some type of resistance reading?
but man, how was it that this amp stillworked even with those diodes in backwards.... :confused:
i guess that 10 ohm resistor in the yellow side ps was taken out to avoid this mess, and jump start it....but now even after i try taking it back out, it still dont work.
(and i thought i was almost finished :bawling:) |
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| Perry Babin |
I don't think the amp could have powered up with the bottom diode reversed unless it was shorted.
The other diode isn't as important. It can probably be left out untill you get the amp to power up.
Legs 1 and 2 of the opto-coupler are the LED. You should get a reading of ~1.25 volts (which you already read a few posts back).
With the bottom diode in correctly and the amp powered up, what's the DC voltage on the 3 legs of the MPSA06 (black lead on ground)?
If the bottom diode is still failing when in correctly, pull the A06 near the opto-coupler. Does the diode still get hot/fail?
The 10 ohm resistor should not have had an effect on this part of the circuit. It could have made the FETs run hot but it couldn't have caused these problems.
This is starting to seem like a test of some sort. I don't know if you're testing us or someone's testing you. :) |
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| Clipped |
i feel the same way man....test....to top it off, the head on my soldering iron has just officially wore out, im gonna take a couple days off from this amp before i go nuts.
maybe this is a sign by the amplifiers gods to sacrifice a pyramid amp. :hot: |
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| Clipped |
ok man, i got everything back together , cleaned the board up a little by the vertical 6488...
powered it up and its back to life....the diode is not burning out...but i currently have a 4005 in there.
the teardrop tantulum by the A06 was bad, i dont know when it went bad, because i changed it....anyway, changed it again.
music plays through it..but,but,but....the output is low and distorts at low volumes...and your going to love this....rail voltage is only 18vdc...
that A06 you asked me to measure is:
e=10.78
b=11.39
c=11.59
18 volts for the rail....and the fets on the orange side still get hotter than the yellow side...that vertical 6488 seems to be getting hotter than it should be...
you asked me before to use a scope to look at the waveform...i dont have a scope, but if it helps...my meter can measure frequency...
if i ever get this thing working properly, im going too be afraid to put it in my car... :xeye: |
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| Clipped |
continued from above post:
-----------------------------------------------
the fets in the ps measure as following for both sides:
pin 1= -1.86 vdc
pin2= 12.3 vdc
pin3= 0.001 vdc
----------------------------------------------
frequency :
pin 1/both sides = 19.85 khz@VDC
pin 2 orange = 62 to 63 khz @VAC
yellow = 57 to 58 khz @VAC
no frequency comes up for VDC
-----------------------------------------------
vertical 6488
pin 1 = 0.539 vdc
pin 2 = 3.6 vdc
pin 3 = 0.001 vdc
L7815
pin 1 = 9.66 vdc
pin 2 = 0.001 vdc
pin 3 = 8.72 vdc
----------------------------------------------
rectifying diode on orange side:
pin 1 = 4.87 vdc
pin 2 = 0.001 vdc (dont forget LOL)
pin 3 = 4.81 vdc
rectifying diode on yellow side:
pin 1 = 4.78 vdc
pin 2 = 9.69 vdc
pin 3 = 4.73 vdc
---------------------------------------------
and it gets weirder
if i measure the secondaries i get 13.8vac, with one lead on one of the center legs and the other on one of the two outer legs.
if i put each lead on an outer leg i get 27.5 vac...
but the rail voltage is +/- 18vdc ....wtf?
18 volt rail voltage isnt because of the inline power resistor is it?
because now im afraid to take it out. |
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