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-   -   Spl dynamics EXT2000d (http://www.diyaudio.com/forums/car-audio/220913-spl-dynamics-ext2000d.html)

zuarus 3rd October 2012 09:32 PM

Spl dynamics EXT2000d
 
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/attachm...7&d=1268986195
Thanks!

zuarus 4th October 2012 09:38 PM

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.

Perry Babin 5th October 2012 02:54 AM

If you don't find the fault, post a photo of the audio driver board.

zuarus 5th October 2012 06:59 AM

Quote:

Originally Posted by Perry Babin (Post 3190394)
If you don't find the fault, post a photo of the audio driver board.

OK.Thanks! I will try to repair it later...

zuarus 6th October 2012 03:56 PM

The sawtooth on tl494 is "modulated". It changes its level.

I have changed tl494, but new one works same. :(

Perry Babin 8th October 2012 03:08 AM

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.


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