I would cut through it. I don't know what sort of tools you have. I've recently been using a plexiglass cutter. If you have one, try it. Otherwise just get through it however you can. If you can tell which side the carbonization is on, start on that side. You only have to cut until you break into clean fiberglass. You don't have to cut all of the way through.
Well it's not the driver board. I doubt I would have the same strange problem with a different driver board.
Can you install the driver board in the other amp?
Is it possible that you installed parts in the boards in the wrong locations in both boards?
Is it possible that you installed parts in the boards in the wrong locations in both boards?
I would have to repair the other amp. I may have to do that just to test the boards.
Just double checked. Q122,123,126&127 are MPSA56
Q120,121,124&125 are MPSA42
Q114,116&118 are MPSA92
Those are the only ones I removed. Checked all the others in circuit.
Just double checked. Q122,123,126&127 are MPSA56
Q120,121,124&125 are MPSA42
Q114,116&118 are MPSA92
Those are the only ones I removed. Checked all the others in circuit.
You only need basic operation. If you install one FET in each bank of the power supply nearest the driver board, the supply should function well enough unless drivers or gate resistors are burned.
You don't need outputs in the circuit.
Is the damage more severe?
You don't need outputs in the circuit.
Is the damage more severe?
Yes I think that is all it needs and I will be able to test the driver boards. I have a few units I need to get repaired tomorrow. I'll get the boards tested as soon as I can and post back with results. Thanks!
![20160609_162242[1].jpg](/community/data/attachments/513/513162-a0276192f4a83a1647fde307233cb270.jpg?hash=oCdhkvSoOh)
![20160609_162356[1].jpg](/community/data/attachments/513/513179-8acede7652bb2db5d88af1c80dac4175.jpg?hash=is7edlK7Lb)
I think you'll have to short the speaker terminals together (using a dummy load should be sufficient) to see the high-side correctly.
Is the low-side going down to the negative rail?
What was the problem?
Is the low-side going down to the negative rail?
What was the problem?
This is the other amp I repaired to test the driver boards. I still have the same problem on the original amp. And yes I wasn't using a load on the test amp.
And yes the low side is going down to the negative rail. on the test amp. So the driver boards should be good.
Do you read 0 ohms between the two grounds (PG and SG) on the driver board when it's in the defective main board?
If you are checking without the driver board in the amp, you need to place the meter probes on the side of the board with only a pad (not on the side with the trace leading to the pad).
If you are checking without the driver board in the amp, you need to place the meter probes on the side of the board with only a pad (not on the side with the trace leading to the pad).
"Do you read 0 ohms between the two grounds (PG and SG) on the driver board when it's in the defective main board?" - Yes. Double checked it.
Everything points to the driver board as the problem but the boards run correctly in the test amp. I'm scratching my head. I don't know what's going on or what to check next. I cut the low side drive trace to isolate it from all the gate resistors and diodes. Signal was the same off the driver board. Tis a mystery indeed.
Everything points to the driver board as the problem but the boards run correctly in the test amp. I'm scratching my head. I don't know what's going on or what to check next. I cut the low side drive trace to isolate it from all the gate resistors and diodes. Signal was the same off the driver board. Tis a mystery indeed.
I was very careful working on it. I use a solder Pullet and wick to pull the board. I'll double check that tomorrow. Plus I checked continuity from the pins to the locations on the main board . All check fine.
With two working amps (even if they're just barely functioning), you can compare voltages at every point. That may help find the fault.
If you do this, clamp all working components down.
If you do this, clamp all working components down.
by the way did you find a sollution?i m working on the same amp....i ve got heat
in two output fets and heat to the driver board also...any suggestion?
in two output fets and heat to the driver board also...any suggestion?
Is the amp working? Do you have output?
Did you have to repair the output?
It's unusual for just a couple of outputs to run hot on this amp. Check the driver board closely. Reread this post starting at #55.
If you have a scope, check your high and low drive off the driver board. You can see what the wave forms should look like in this post. I've posted pics.
Be sure and check the gate resistors and diodes to the outputs. You will have to unsolder the diodes to test them properly.
I'm sure someone else will offer up advice. Good luck.
Did you have to repair the output?
It's unusual for just a couple of outputs to run hot on this amp. Check the driver board closely. Reread this post starting at #55.
If you have a scope, check your high and low drive off the driver board. You can see what the wave forms should look like in this post. I've posted pics.
Be sure and check the gate resistors and diodes to the outputs. You will have to unsolder the diodes to test them properly.
I'm sure someone else will offer up advice. Good luck.
sorry being late.....i ll check again....the power supply was blown up...
now is working fine....i have checked the gate diodes and resistors...i have also checked the driver boaed but is still getting hot....with no output fets is getting hot in about 15 seconds...
now is working fine....i have checked the gate diodes and resistors...i have also checked the driver boaed but is still getting hot....with no output fets is getting hot in about 15 seconds...
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