Another MTX 81000D

[Hexhclass]

This amp came in with C250 blown,I replace it and it pop again.I don’t see no oscillation on the outputs .A high frequency noise can be heard coming from the amp.

Any suggestions on that one?

 

[Perry Babin]

The regulator likely failed and also destroyed the optocoupler. The parts are shown on the MTX 81000 page if you have the tutorial. If not, let me know and I'll paste the diagram.

 

[Hexhclass]

In the 81000 folder i don't see a schematic

 

[Perry Babin]

It's on the following page.
repair_tutorial/miscellaneousstuff/mtx/mtx81000d/mtx81000dwaveformsandnotes.htm

You can just perform a search for the following file in the tutorial folder.
mtx81000dwaveformsandnotes.htm

If your copy is more than a few months old, you should get a new copy. It costs nothing but the time it takes to download it.

 

[Hexhclass]

The copy I have is a earlier one

In the repair notes I see there is a zener D260 that goes open but I did not locate it on the board yet.

 

[Perry Babin]

With the regulators that they use you can expect most of the regulators components in that particular regulator to be defective and if you miss only one defective part, it can destroy all of them again.