OK, the amp in question is an integrated DC amp by Fisher. It's in the same family as a couple other CA 2xxx models, with the 2420 having more features, and being an 80 wpc variant. It uses the STK 0080 II Darlington packs, and has the voltage amplifier STK 3082 smack in-between those. This particular unit is CLEAN inside, with NO popped fuses, and IS getting power to each fuse. Absolutely no corrosion, all switches have had deoxit treatments, and all the soldered joints look good with no excess flux or signs of overheating. I did reflow a couple solder joints that looked weak. I got a good deal on this as well.
Anyways, none of the inputs are working correctly i.e. Tuner, Aux, Tape, and I haven't tried Phono as I only have a CD player and PC. Each section has a dedicated light for what's selected, so the switch is working. However, the EQ in (Power Control as worded on the back) DOES work as the amp plays full blast with it, but it's in tone defeat mode, and balance + volume aren't controllable with it. I used headphones for the testing as I didn't want to overdrive my speakers. Using my PC, and adjusting volume with that, I was able to listen to it for a few hours via the EQ input, so the amp section is at least working. After the initial deoxit cleanings, I was able to hear through Aux input, but it's rather quiet. The built-in EQ was responding as well with the Aux in, but balance was not and volume was not. Volume at full amount, seemed to bring the right channel up (barely), but it was still quieter than left channel, and both are nowhere near correct output levels. I'm stumped. Could it be a preamp section failure? There are 2 transistors with the 3 prongs and the metal tabbed back, and they are getting really hot, so it would seem they are doing something. I can't find a schematic for this either, and want to avoid buying "Chinese" photocopied manual of e-pay unless absolutely needed. I have a line on a parts unit that works, and has external parts I'd need to correct a few issues, so hopefully internal stuff is similar enough as well. But the no sound from the inputs is stumping me. I'd like to get this working, as it's gotta be one of the quietest amps I've ever heard through headphones as far as THD goes. Listening through the EQ in yesterday, it was like the amp wasn't even on. No hiss, no hum, just music. And I could also hear things in the audio that doesn't get detected with my other unit, like a thumb sliding down on a guitar string LOL. Ideas?
Anyways, none of the inputs are working correctly i.e. Tuner, Aux, Tape, and I haven't tried Phono as I only have a CD player and PC. Each section has a dedicated light for what's selected, so the switch is working. However, the EQ in (Power Control as worded on the back) DOES work as the amp plays full blast with it, but it's in tone defeat mode, and balance + volume aren't controllable with it. I used headphones for the testing as I didn't want to overdrive my speakers. Using my PC, and adjusting volume with that, I was able to listen to it for a few hours via the EQ input, so the amp section is at least working. After the initial deoxit cleanings, I was able to hear through Aux input, but it's rather quiet. The built-in EQ was responding as well with the Aux in, but balance was not and volume was not. Volume at full amount, seemed to bring the right channel up (barely), but it was still quieter than left channel, and both are nowhere near correct output levels. I'm stumped. Could it be a preamp section failure? There are 2 transistors with the 3 prongs and the metal tabbed back, and they are getting really hot, so it would seem they are doing something. I can't find a schematic for this either, and want to avoid buying "Chinese" photocopied manual of e-pay unless absolutely needed. I have a line on a parts unit that works, and has external parts I'd need to correct a few issues, so hopefully internal stuff is similar enough as well. But the no sound from the inputs is stumping me. I'd like to get this working, as it's gotta be one of the quietest amps I've ever heard through headphones as far as THD goes. Listening through the EQ in yesterday, it was like the amp wasn't even on. No hiss, no hum, just music. And I could also hear things in the audio that doesn't get detected with my other unit, like a thumb sliding down on a guitar string LOL. Ideas?
! It didn't come with any, and I didn't realize a jumper was needed. No sound in the right channel, but that's because I need to replace the volume pot which has broken traces unfortunately. Left channel powered right up with RCA jumpers though. So thank you for chiming in!
but oh well. It need a new volume pot anyways, which seems I'll have to go through a parts unit for one which is fine.
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