I probably have another problem none of the trans got hot and the power light was still coming on. i checked temp on trans after that snap all was room temp.
Perry i replaced that diode but current draw is still to much, i can hear light crackling noises and i think its coming from the tl494 chip, with only about 4-5 sec of power tl494 got up to 94 deg. Could it be drivers are bad and fried tl494?
Measure the DC voltage on pins 9 and 10 of the 494. Then measure the DC Voltage on the gate legs of the power supply FETs. Post those voltages.
With only ground and remote:
Pin 9: 5.28v
Pin 10: 5.28v
Center leg q6: 111mv
Center leg q7: 114mv
Bias pots still turned all the way down
Pin 9: 5.28v
Pin 10: 5.28v
Center leg q6: 111mv
Center leg q7: 114mv
Bias pots still turned all the way down
Im sorry im trying to learn i really want to fix this amp. I was in a hurry and didnt think it thru. 2 questions is ground and remote ok for this check? And do i need to turn bias pots up there all the way down now?
All you need are ground and remote.
Without B+, there is no secondary voltage being generated for the audio circuit so the bias is not a concern.
Without B+, there is no secondary voltage being generated for the audio circuit so the bias is not a concern.
Those voltages would make it appear that the drivers are OK. If the 494 is heating up to 90c quickly, it's likely defective. You could lift terminals 9 and 10 (carefully, not to damage the pads) to see if it still heats up but it probably will.
Yes when i had +b and remote hooked up yesterday it got hot quick only like 5 sec on and then after turned off. I waited a 10 to 20 sec then measured heat and it was like 95deg. And something was making crackling noises that i think was coming from tl494. Also this amp had both ps fets popped and all outputs bad.
Perry i have never removed a chip like this. Hows best way to do this? Maybe bending up legs? Or i thought about clipping the legs then unsoldering them?
It's a high-temperature tape that's used as an insulator sometimes.
Do you have desoldering braid?
Do you have desoldering braid?
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