Ok i also noticed that they have "flipped" 540 and 9540
in the schematic.
On the 540 its
G
D
S
And the 9540 its
S
G
D
But i guess they only flipped it in the schematic?
IRF9540
http://www.elfa.se/pdf/71/07116395.pdf
And IRF540
http://www.elfa.se/pdf/71/07114952.pdf
Can you please take a quit look, will it work?
What is the most important thing to look for in a replacement transistor?
And remember, i will learn by this so i dont have to ask later on!
Thanks again.
in the schematic.
On the 540 its
G
D
S
And the 9540 its
S
G
D
But i guess they only flipped it in the schematic?
IRF9540
http://www.elfa.se/pdf/71/07116395.pdf
And IRF540
http://www.elfa.se/pdf/71/07114952.pdf
Can you please take a quit look, will it work?
What is the most important thing to look for in a replacement transistor?
And remember, i will learn by this so i dont have to ask later on!
Thanks again.
As far as I know, the pin configuration (left to right, GDS) is the same for all TO-220 package FETs. Someone should correct me if they know of any exceptions.
The most important thing in a replacement is generally getting the exact same part number component. As for specs, current and voltage ratings are the most important if you're looking for substite parts. Only use subs when the original part number isn't available.
The most important thing in a replacement is generally getting the exact same part number component. As for specs, current and voltage ratings are the most important if you're looking for substite parts. Only use subs when the original part number isn't available.
I now replaced all 6 transistors and i think it went OK.
Now all drivers gett equally varm, but the funny thing is
that they still get quite hot after a couple of minutes.
Still i can hold my hand on them but it burns.
Must be something wrong, what could it be?
And why does the remote work if i disconnect
the two big connectors on the amp board?
Now all drivers gett equally varm, but the funny thing is
that they still get quite hot after a couple of minutes.
Still i can hold my hand on them but it burns.
Must be something wrong, what could it be?
And why does the remote work if i disconnect
the two big connectors on the amp board?
Are you still having trouble getting the amp to power up when the remote voltage is applied 'after' the B+ and ground connections are made?
It's probably normal for the drivers to run hot. If the voltage across the drivers is close to the voltage listed in the manual, they will be dissipating ~1/4 watt of power. That's enough to make a small transistor with no heatsink run hot.
It's probably normal for the drivers to run hot. If the voltage across the drivers is close to the voltage listed in the manual, they will be dissipating ~1/4 watt of power. That's enough to make a small transistor with no heatsink run hot.
Ok, yes i still have the remote problem. But if i disconnect
the two of the big connectors from the board it will work.
So maybe its not a ground problem? Or is it? :S
Now im confused, still it will work if i wire RCAshield to
terminal ground.
Could it be a dead short to ground somewhere that makes the current to take the wrong way?
Hm...thinkthinkthink..
the two of the big connectors from the board it will work.
So maybe its not a ground problem? Or is it? :S
Now im confused, still it will work if i wire RCAshield to
terminal ground.
Could it be a dead short to ground somewhere that makes the current to take the wrong way?
Hm...thinkthinkthink..
I dont use a signal source when testing, but when i do test i use a portable CD player. And i use a small 12v car battery to power the amp with
Its strange because i have checkt all the traces cant se damages.
Maybe i have to measure ALL resistors and everything, could take me a week.
And the capacitors are hard to now if they are OK.
Its strange because i have checkt all the traces cant se damages.
Maybe i have to measure ALL resistors and everything, could take me a week.
And the capacitors are hard to now if they are OK.
Some amplifiers won't work properly if the signal source shield isn't grounded. The shield of the RCA signal cable of a standard head unit is connected to the chassis ground of the head unit. When you plug the RCA cables into the amp, it grounds the shield. With the portable CD player, the shield is left floating and the amp may not work properly.
It's difficult to be certain on this amp because Alpine used the same ground symbol for both the primary and secondary grounds but it appears that the speaker DC offset protection is referenced to chassis ground while the signal is taken from the speaker output (which is on the secondary/floating side of the power supply). This could cause false triggering of the DC offset protection.
R525 looks like it should prevent false triggering by keeping the secondary within ~1/2v of the chassis ground. You may want to check it to make sure it's within tolerance. It should be easy to find. It's a 150 ohm 1 watt component.
Throw it in the trash can?
This amp has been an easy repair so far. It just takes a bit longer to troubleshoot via a forum. I've had amps that took days to troubleshoot on the bench and I didn't throw any of them in the trash.
It's difficult to be certain on this amp because Alpine used the same ground symbol for both the primary and secondary grounds but it appears that the speaker DC offset protection is referenced to chassis ground while the signal is taken from the speaker output (which is on the secondary/floating side of the power supply). This could cause false triggering of the DC offset protection.
R525 looks like it should prevent false triggering by keeping the secondary within ~1/2v of the chassis ground. You may want to check it to make sure it's within tolerance. It should be easy to find. It's a 150 ohm 1 watt component.
Throw it in the trash can?
This amp has been an easy repair so far. It just takes a bit longer to troubleshoot via a forum. I've had amps that took days to troubleshoot on the bench and I didn't throw any of them in the trash.
Hi berry!
I tryed what you said, i connected the amp to a pioneer
head unit, and it worked!
Turned it on off with remote and it worked!
And it played! For about 1 minute, then the channel
wich i replaced the output transistors on went down
and my thin +12v (for test purpose) kabel nearly melted.
And the DC-DC drive transistors became quite hot.
Q313-318
Still the other channel was upp and running.
What happend!? Is this an Amp From Hell?
Must be a short somewhere because the kabel went
hot.. I think it may be some of the 313-318. But why!?
It played music and everything, didnt sound strange.
I played it bridged over both channels so the load
should been equal on both channels, right?
Hmm.. tell me what you think, dont have the strain
to measure tonight.
I tryed what you said, i connected the amp to a pioneer
head unit, and it worked!
Turned it on off with remote and it worked!
And it played! For about 1 minute, then the channel
wich i replaced the output transistors on went down
and my thin +12v (for test purpose) kabel nearly melted.
And the DC-DC drive transistors became quite hot.
Q313-318
Still the other channel was upp and running.
What happend!? Is this an Amp From Hell?
Must be a short somewhere because the kabel went
hot.. I think it may be some of the 313-318. But why!?
It played music and everything, didnt sound strange.
I played it bridged over both channels so the load
should been equal on both channels, right?
Hmm.. tell me what you think, dont have the strain
to measure tonight.
yes they were tightly clamped to the heatsink.
when i bought the new transistors i also bought
new "isolation sheets" for them and thermal grease.
But i tought that before i new if it was working with
the new transistors i did not replace the isolators.
And i did not putt any new grease.
But i made sure that they did not come in contact with
the heatsink and i measured it after i mounted them
tightly.
Trust me during the short monent i was playing
music the outputs did not come near to beeing overheated.
I put my finger on them.. Byt the power transistors where hot!
And my +12v nearly glowed...to thin cable.
when i bought the new transistors i also bought
new "isolation sheets" for them and thermal grease.
But i tought that before i new if it was working with
the new transistors i did not replace the isolators.
And i did not putt any new grease.
But i made sure that they did not come in contact with
the heatsink and i measured it after i mounted them
tightly.
Trust me during the short monent i was playing
music the outputs did not come near to beeing overheated.
I put my finger on them.. Byt the power transistors where hot!
And my +12v nearly glowed...to thin cable.
I'd try replacing them again. When you power it up next time, do so through a 10 amp inline fuse.
Remove the old insulators and clean all of the old compound from the heatsink mating surface and from the insulators. The mica insulators are very good. If you've purchased a different type, I'd recommend using the old mica insulators. Reapply compound to the sink mating surface and the transistors and make sure they're clamped well. Apply just enough compound so that a small bead is displaced all around the transistor when its tightened to the sink. You want the grease to be displaced evenly all around. If it's only displaced near the top of the transistor (where the clamping pressure is the greatest), you need to apply pressure to the lower part of the transistor. When you push it down, you should see the compound displaced and when you release pressure, the transistor should not try to lift again. If the entire transistor is not tightly clamped to the sink, it will overheat and fail.
The bias pot may also be defective (intermittant). When you adjust the biasing again, move the bias pot slightly back and forth (rotation) while monitoring the voltage across the test points. There should not be any significant changes in the voltage across the test points. If there is, the pot may need to be replaced or cleaned.
Remove the old insulators and clean all of the old compound from the heatsink mating surface and from the insulators. The mica insulators are very good. If you've purchased a different type, I'd recommend using the old mica insulators. Reapply compound to the sink mating surface and the transistors and make sure they're clamped well. Apply just enough compound so that a small bead is displaced all around the transistor when its tightened to the sink. You want the grease to be displaced evenly all around. If it's only displaced near the top of the transistor (where the clamping pressure is the greatest), you need to apply pressure to the lower part of the transistor. When you push it down, you should see the compound displaced and when you release pressure, the transistor should not try to lift again. If the entire transistor is not tightly clamped to the sink, it will overheat and fail.
The bias pot may also be defective (intermittant). When you adjust the biasing again, move the bias pot slightly back and forth (rotation) while monitoring the voltage across the test points. There should not be any significant changes in the voltage across the test points. If there is, the pot may need to be replaced or cleaned.
Ohh no dont tell me that i have to buy 6 new transistors
They cost me over 12$ in US money..
But i get the feeling that the output transistors did not
match the old ones.. they were not identical.. But still
IRF540 and IRF9540... but the old ones had some
prefix after..
Think i will measure both power transistors
and output to se if there are more shorted pins
before i power it upp next time.
But could a shorted output transistor make the
+12v wire glow?? 2,3mm thick..(or thin whatever you want
They cost me over 12$ in US money..
But i get the feeling that the output transistors did not
match the old ones.. they were not identical.. But still
IRF540 and IRF9540... but the old ones had some
prefix after..
Think i will measure both power transistors
and output to se if there are more shorted pins
before i power it upp next time.
But could a shorted output transistor make the
+12v wire glow?? 2,3mm thick..(or thin whatever you want
When you said that the channel went down, I assumed that the FETs failed. You need to check them to confirm that they've failed.
If the outputs failed, that could cause the power supply transistors to get hot but other problems can also cause the power supply transistors to overheat.
Can you tell me all of the parts you've replaced so far?
If the outputs failed, that could cause the power supply transistors to get hot but other problems can also cause the power supply transistors to overheat.
Can you tell me all of the parts you've replaced so far?
I first replaced ZD503 it was shorted. think it was a 6.1 zener.
Didnt noticed som change. Placed on the bottom right corner
of "Schematic Diagram 2/2 CORRECTION"
Then i had to replace 2SA 1358 after an accident
was doing some measuring and then oops...
i shorted two of the legs I was not happy!
I also had to replace the zener ZD303 or 304 that blew..
dont remember wich of them. but its in serie with the
2SA1358 (regulator pre). And just in case i replaced
the electrolyts paralell to the ZD303.. On both sides,
and i did not turned them the wrong way.
But that was on the other channel thats working!
not the channel wich had a shorted output transistor.
And yeasterday i replaced Q211-214 + the other
IRF540 and IRF9540 on the small verticall board paralell
with the others.. Thats it.
(DC-DC drive)
I dont replaced Q313-318.. but they went hot now when
something broke.
Didnt noticed som change. Placed on the bottom right corner
of "Schematic Diagram 2/2 CORRECTION"
Then i had to replace 2SA 1358 after an accident
was doing some measuring and then oops...
i shorted two of the legs
I was not happy!I also had to replace the zener ZD303 or 304 that blew..
dont remember wich of them. but its in serie with the
2SA1358 (regulator pre). And just in case i replaced
the electrolyts paralell to the ZD303.. On both sides,
and i did not turned them the wrong way.
But that was on the other channel thats working!
not the channel wich had a shorted output transistor.
And yeasterday i replaced Q211-214 + the other
IRF540 and IRF9540 on the small verticall board paralell
with the others.. Thats it.
(DC-DC drive)
I dont replaced Q313-318.. but they went hot now when
something broke.
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