resistance @ pin 9 of u2 and pin 18 of 3526 is .3ohms
@ pin 10 on u2 and pin 18 of 3526 its .2 ohms
@ pin 10 on u2 and pin 18 of 3526 its .2 ohms
Try measuring the voltage on those 3 pins again to see if you get the same voltage on all of them.
Do you know why the previous voltages listed were not 4.9v?
We need to determine why the voltages aren't consistent. Without reliable voltage readings, it's going to be nearly impossible to troubleshoot.
We need to determine why the voltages aren't consistent. Without reliable voltage readings, it's going to be nearly impossible to troubleshoot.
i cannot post voltages tonight, have to file taxes.
but if it makes any difference, amp has to be tested with the large 250amp fuse that came with amp. amp blows the 15 and 30amp fuses i have been trying to use.
also while soldering one of the smd resistors i had a trade peel up from the pad. i pushed it back down, then soldered smd resistor to it, then test resistance from right side of resistor, to right leg of mosfet it was paired with(which id where the trace ran) and got the 20 ohms of the 20r0, which tested the connection as being good.
while looking @ amp earlier, saw a small strand of wire touching across two legs of a mosfet, but i have a feeling this happened recently as it came from my power wire running from my battery, and cover was on amp upon first testing of amp/
but if it makes any difference, amp has to be tested with the large 250amp fuse that came with amp. amp blows the 15 and 30amp fuses i have been trying to use.
also while soldering one of the smd resistors i had a trade peel up from the pad. i pushed it back down, then soldered smd resistor to it, then test resistance from right side of resistor, to right leg of mosfet it was paired with(which id where the trace ran) and got the 20 ohms of the 20r0, which tested the connection as being good.
while looking @ amp earlier, saw a small strand of wire touching across two legs of a mosfet, but i have a feeling this happened recently as it came from my power wire running from my battery, and cover was on amp upon first testing of amp/
also found a strand of wire touching between the 5+ volt reference point and delay point on ribbon cable that runs between power board and output board.
Wire strands in these amps can cause a lot of problems. You need to go over every square inch of the boards with a magnifying glass in bright light to find any remaining strands. Look behind the legs of the transistors also.
k will do that. so do u think this may be causing the issue? if not what would your best guess be right now? thanks
It's a problem that can cause catastrophic failure of the amp. I don't know if it's causing the problems. I'd recommend that you use some canned air and blow it under all of the
ICs and capacitors (no power applied). The strands can hide under those and cause intermittent problems.
ICs and capacitors (no power applied). The strands can hide under those and cause intermittent problems.
alright back with voltages. i measured everything 3 time, and if the measurement was questionable, i confirmed with a second meter.
1-.024
2-4.8
3-18.56
4-.11
5-2.0
6-4.96
7-3.6
8-4.95
9-4.89
10-4.8
11-6.8
12-.001
13-6.13
14-6.13
---------------------------
1-4.8
2-17.4
3-18.7
4-.4
5-2.38
6-5.17
7-4.95
8-.58
9-5.4
10-.48
11-1.5
12-.017
13-.5
14-4.94
1-.024
2-4.8
3-18.56
4-.11
5-2.0
6-4.96
7-3.6
8-4.95
9-4.89
10-4.8
11-6.8
12-.001
13-6.13
14-6.13
---------------------------
1-4.8
2-17.4
3-18.7
4-.4
5-2.38
6-5.17
7-4.95
8-.58
9-5.4
10-.48
11-1.5
12-.017
13-.5
14-4.94
no, its still going into protect mode. i believe there's short or something somewhere causing it to appear in protect mode. the led light on the board while in protect mode is supposed to be a constantly lit led, orange. instead i have a blinking orange led, when i touch some of the pins with the meter probe it seems to effect the rate it is flashing. especially pin 18 on one of the ic's. it would almost be fully lit without blinking at some points.
What make/model meter are you using?
There still appear to be problems with accuracy. For example, Pins 9 and 10 of U2 should be identical but they're not. Some of the voltages are critical and 0.01v could make a significant difference.
There still appear to be problems with accuracy. For example, Pins 9 and 10 of U2 should be identical but they're not. Some of the voltages are critical and 0.01v could make a significant difference.
im using a fluke 77 series II, and rechecking with the bluepoint meter, also when i check three time, i get the same number repeatedly(on the steady voltages like the 18.56). Also when i am checking these voltages, some of them fluctuate with the blinking of the light. some shoe a voltage then drop out to OL with the blinking of the light.
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OK. Pins 6 and 7 of U3 aren't producing the correct output. With pin 7 lower than pin 6, the voltage on pin 1 should be very near 0v.
Re-check them. Notice whether they're steady or not. When checking pins 6 and 7, you may want to have one meter on pin 1 to see if the meter is causing 1 to change when on 6 or 7.
Re-check them. Notice whether they're steady or not. When checking pins 6 and 7, you may want to have one meter on pin 1 to see if the meter is causing 1 to change when on 6 or 7.
okay retested 6 and 7 on both ic's.
max voltage i got on first ic on pin 6 is 4.96(steady no flashing) pin 7 5.12(flashing)
is#2 pin 6 5.22 (flashing) pin7 4.96 steady.
ill will do the pin 1 while on 6 or 7 tomorrow morning.
also it seems output mosfets on channel two are getting warm, where as channel one mosfets aren't even warm to touch at all.
max voltage i got on first ic on pin 6 is 4.96(steady no flashing) pin 7 5.12(flashing)
is#2 pin 6 5.22 (flashing) pin7 4.96 steady.
ill will do the pin 1 while on 6 or 7 tomorrow morning.
also it seems output mosfets on channel two are getting warm, where as channel one mosfets aren't even warm to touch at all.
okay tested the way you described with a probe of one meter on 6 or 7 and another meters probe on one. the maximum voltage i got while it was flashing to OL was 5.5 ON ic #1 and 6.5 on ic #2.
i do notice i get a squeak sound when testing pin 14 on ic #2. the squeak goes along with the flashing protect light. and while testing some of the other pins it seems the rate of the flashing light slows down.
i also get the same higher voltage readings without touching pin 6 or 7 using bluepoint meter. also the "squeak" only happens while using the bluepoint meter.
i do notice i get a squeak sound when testing pin 14 on ic #2. the squeak goes along with the flashing protect light. and while testing some of the other pins it seems the rate of the flashing light slows down.
i also get the same higher voltage readings without touching pin 6 or 7 using bluepoint meter. also the "squeak" only happens while using the bluepoint meter.
In the future, refer to the ICs by their circuit board designations (U2 and U3 for the LM339Ss). U1 is the SG3526.
On U3 (for all questions here), did probing pin 6 cause pin 1 to fluctuate?
If so, what was the range of voltage on pin 1 (use the bluepoint on pin 1)?
Do you still have higher voltage on pin 6 than on pin 7?
Is pin 1 still near 5v?
On U3 (for all questions here), did probing pin 6 cause pin 1 to fluctuate?
If so, what was the range of voltage on pin 1 (use the bluepoint on pin 1)?
Do you still have higher voltage on pin 6 than on pin 7?
Is pin 1 still near 5v?
okay on ic U3 probing pin 6 did not cause pin 1 to fluctuate(yet i am dealing with a flashing voltage up and down but max of pin 1 did not get higher or lower)
i do still have higher voltage on pin 6 than 7(pin6-5.37)(pin7-4.96)
and pin one is still near 5 volts @ 4.86
i do still have higher voltage on pin 6 than 7(pin6-5.37)(pin7-4.96)
and pin one is still near 5 volts @ 4.86
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