Adcom GTP-750 problems

Bigbang

I just purchased an Adcom GTP-750 Pre/Tuner. The owner disclosed that it may have issues and wanted 40 bucks for it. It had the remote so I thought I'd take a chance. Surprise! It turns out that its nothing simple like a fuse or some noticeable damage to the power supply. After taking the cover off and poking around everything looks connected. The caps all look good. Nothing hums loud. Nothing obvious.

When I plug it in and turn it on, the amber light on the power button comes on and stays on. I get no display and none of the buttons seem to work. The remote also does not seem to make any change to the system. I have not tried to connect a source to it and plug it into my amp.

Can anybody help me with what to try next?

Thanks,

David

zingo

Look for damage on any of the logic boards or chips. It seems like your controllers aren't working. Also test for voltages at the outputs on the power supply, and in to applicable boards.

Bigbang

Thanks. Nothing obvious after inspecting each board. I did hit the power board with a little deoxit and lost the amber light or any light on the power button. I'll hunt down my multimeter this weekend and check power to the controller boards. Everything is very well labeled on the boards.

Bigbang

ok. I found my multimeter and did a little probing. I gave about 95 vac going into the board that handles the power. I switched to dc and did not find any output from any of the jumpers going to the other boards.

when I turn the unit on there is a hard click from what I think is some kind of relay switch. Its a larger component near where the power comes into the unit and right next to what I think is a transformer measuring about 1 1/2" by 1/2" labeled 12VDC.

does that give anybody any ideas. What should I do next?

Thanks guys!

David