I got this amp thismornIng. The power led lights and protect stays off. I can hear the relay kick on but no sound. Came to me with 7 out of eight power fets blown. Checked gate resisters and replaced fets with new. Still no sound. Any ideas?
Is it producing both positive and negative rail voltage?
Do you have both positive and negative 15v on the power supply pins of the op-amps?
What is the DC voltage on pine 10, 11 and 12 of the TL494?
Do you have both positive and negative 15v on the power supply pins of the op-amps?
What is the DC voltage on pine 10, 11 and 12 of the TL494?
I found the problem. All mosfets I replaced are bad. Pulled and diode checked all just the be sure. And found all bad. I need a new supplier. Anyone know where I can order from?
With the power supply FETs out of the circuit, check the DC voltage at the gate pad of the FETs. Is it the same for all FETs and all approximately 5v?
Is the circuit board green or red?
Is the circuit board green or red?
The Pcb is red. It looks as someone else tried to repair before. There is a resister that looks as if someone put it there by hand. It's not even all the way on the board.
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From what I can tell there were some factory corrections on these. I have two of them that I am working on right now and they both have some some ceramic capacitors that are bypassing to ground from R207,228 and across R168 to some terminal rings on the board mounting screws.
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