Hi,
Anyone out there have the Service Manual or Schematic for a ADCOM GFA-7500 five channel amplifier? Thanks..
Anyone out there have the Service Manual or Schematic for a ADCOM GFA-7500 five channel amplifier? Thanks..
I'll bet, given 5 tons of crap in a 2 ton bag. 🙂 I recently repaired a Sherbourne 7 channel amp that had literally 1/4" of space between channel module heatsinks. That was NOT fun to work on. And 115lbs to lug around, too.
If I may ask, what tool did you use to remove the 5/16 nuts holding the module to the speaker binding posts? I've gotten that far, but can't find a socket just small enough, but deep enough to accept the length of the rod on that post. My deep socket is too long to fit in that space. How did you disassemble and reassemble that?
Sorry I don't remember the size of the wrench I used.
What do remember is the amp needs to be turned upside down. Disconnect wires to small AC pcb mounted to bottom of case or remove mounting screws. I don't remember which I did. Watch out for washers and such. With the top cover and ALL screws installed turn amp upside down and remove bottom cover. Now use wrench to un-tighten bottom speaker post. Do the other also if possible. Re-install bottom cover leaving out the individual heatsink screws. Turn amp over, remove top cover, all back screws, disconnect amp wiring. Un-tighten last speaker post. All this is easier to do with one amp module removed so reinstall is easier. I may of forgotten something but you get the idea. I sold the amp some time ago.
What do remember is the amp needs to be turned upside down. Disconnect wires to small AC pcb mounted to bottom of case or remove mounting screws. I don't remember which I did. Watch out for washers and such. With the top cover and ALL screws installed turn amp upside down and remove bottom cover. Now use wrench to un-tighten bottom speaker post. Do the other also if possible. Re-install bottom cover leaving out the individual heatsink screws. Turn amp over, remove top cover, all back screws, disconnect amp wiring. Un-tighten last speaker post. All this is easier to do with one amp module removed so reinstall is easier. I may of forgotten something but you get the idea. I sold the amp some time ago.
Okay, so there is no shortcut. 🙁 I was concerned that a complete teardown might be the only way to do this. Just to get two modules at opposite ends out.
Thanks for detailing how you did it. I have to figure out the hours and let the customer decide if he wants to go forward with the repairs.
Thanks for detailing how you did it. I have to figure out the hours and let the customer decide if he wants to go forward with the repairs.
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I understand your thought process on this one. Looks like allot of work. I let the amp sit for weeks as I thought, do I really want to do that much work..... Once I found the right wrench it was way easier than I thought. My apologies, I thought the heatsinks were screwed to the top cover as well, a different amp I guess... Perhaps I installed the bottom front heatsink screw for each amp. Then lifted the front of the amp to remove the screw. This avoided the problem of the dangling module when upside down. To reinstall, I supported the modules with a book/mag or something like that while I tightened the speaker posts. I think you'e going to need to remove all the modules.
Anyway, I recapped the whole amp and some other bad parts.
Anyway, I recapped the whole amp and some other bad parts.
Either way, it's a lot of work several hours at the least. Not to mention the actual troubleshooting and repair of two failed modules and this unit. The customer doesn't want to spend more than $300 total and it's going to come to weigh more than that with all this disassembly so I think he's probably going to opt to just buy a new amplifier. It's a shame, but he's 77 years old and probably doesn't want to spend money on a repair without having at least a five year warranty.
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