Hello!
I need an advice.
I have broken d-class amp. It produces a noise (frequency near 5k). And coils in output filter becomes hot.
I disconnected preamp (all opamps). Noise is not stopped. All mosfets were desoldered and tested. They all are OK.
The amp is old.
Here is the schematic.
http://www.bassclub.ru/forum/attachment.php?attachmentid=10957&d=1268986195
Thanks!
I need an advice.
I have broken d-class amp. It produces a noise (frequency near 5k). And coils in output filter becomes hot.
I disconnected preamp (all opamps). Noise is not stopped. All mosfets were desoldered and tested. They all are OK.
The amp is old.
Here is the schematic.
http://www.bassclub.ru/forum/attachment.php?attachmentid=10957&d=1268986195
Thanks!
I take an oscilloscope and find distorted squarewave at gates of irf064.
So I find not soldered pin 10 of Tl494. I will solder it tomorrow.
The amp was in service. And TL494 was changed. There are a lot of gumboil. I think serviceman was lowqualified.
So I find not soldered pin 10 of Tl494. I will solder it tomorrow.
The amp was in service. And TL494 was changed. There are a lot of gumboil. I think serviceman was lowqualified.
The sawtooth on tl494 is "modulated". It changes its level.
I have changed tl494, but new one works same. 🙁
I have changed tl494, but new one works same. 🙁
Last edited:
How low is the DC voltage dropping on the following pins:
Pin 11
Pin 12
Pin 14
Place the black probe on pin 7 when measuring.
Pin 11
Pin 12
Pin 14
Place the black probe on pin 7 when measuring.