Torben Espoe wrote:
Hi
I have recently tried to repair a T762, not very succesfull I'm afraid.
The story is this: I was listening to music one day and suddenly the amp
shuts down with at loud POP in the speakers and red light in the status led.
I turn it off and then on again and now there is nothing coming out of the
speakers, other than hum when I turn the volume up to max. After some
checking I find that it can still switch between video feeds and the main
amps still work if I use direct input.
After some seaching in the schematics I'm guessing that it has to do with a
missing voltage, and sure enough the +12V is missing. After half an hour of
disassembling I have the motherboard out, and I measure the 5V1 zeners and
one is dead. I exchange all 5V1 zeners with 5W types an reassemble the amp,
but now it will not turn on.
The status light is amber, but no turn on. I measure the power on +13V and
find it about 6,5V at D712. it seems that some thing on the +5,6V is drawing
to much current for the poweron trafo.

Does anybody have any sugestions?

Torben

email exchange TWO with 2




Torben,

I'd start by checking that all of the plug in cables are seated. The
one that (as I recall) runs from the keyboard (front panel) down to the
mother board (4 pin black wire) is easy to forget. Be aware that I may
be thinking of the T753, which I see more of. Also, be sure that the
trigger switch on the rear (if so equipped) is in the correct position.
It's easy to move by accident when putting the amp back together.

Regards,
Tim Schwartz