Carbsandcaps
Super Member
I picked up this HealthKit AR-15 receiver for a decent price. When I got it, it had 1 working channel and that was weak. The through help of people on audio karma I was able to get what I think might be the best sounding solid state receiver I’ve ever heard!
First things first check the outputs and found 2 of them dead. Replaced them and then the magic smoke came to visit. Found one of the .68ohm emitter resistors open. All I had was .5ohm so i through them in and with the help of members I put a 1000ohm trim pot in parallel with one of the stabister diodes to adjust the bias. Got it all back together and one of the .5pm resistors glowed like a vacuum tube and went out.
Decided to remove both amp boards and start rebuilding. I found at least 10 dark brown composite resistors way out of range. Replaced all the brown resistors and driver transistors while I was there.
I decided to try the to-3 to to-3p conversion while I was there because, why not? I had some scavenged to-247 transistors from a surround sound receiver (old surround receivers are a treasure trove of useable parts) and modified them to install without modifying the heat sink.
Put everything back together and nothing blew up! Set the bias to 30mv and went to work on the preamp/tone board. I know I’ll catch flack for this part but I replaced all of the 10uf signal path catalytic capacitors with (2) 4.7uf capacitors in parallel. There was 2 reasons for this 1: the 10uf would have been too tall and would not have let the board fit back in and also 4.7uf was all I had and at $30 for 50 of them it was considerably cheaper than using 10uf’s (there’s something like 12-14 10uf caps in the signal path). Replaced the monster 8000uf main filter capacitor with 3 4700uf caps, replaced the output capacitors with some nichicon gold caps, Cleaned all the controls and reassembled it. Hooked it up to my realistic minimus 7 test speakers and wow!
I have it playing though my rebuilt Jensen 700xl speakers now. I’m not joking that this is one of, if not the best sounding solid state receiver I’ve heard. It should be noted that I prefer tube receivers but this thing is close to my fisher x-100-b in warmth.
First things first check the outputs and found 2 of them dead. Replaced them and then the magic smoke came to visit. Found one of the .68ohm emitter resistors open. All I had was .5ohm so i through them in and with the help of members I put a 1000ohm trim pot in parallel with one of the stabister diodes to adjust the bias. Got it all back together and one of the .5pm resistors glowed like a vacuum tube and went out.
Decided to remove both amp boards and start rebuilding. I found at least 10 dark brown composite resistors way out of range. Replaced all the brown resistors and driver transistors while I was there.
I decided to try the to-3 to to-3p conversion while I was there because, why not? I had some scavenged to-247 transistors from a surround sound receiver (old surround receivers are a treasure trove of useable parts) and modified them to install without modifying the heat sink.
Put everything back together and nothing blew up! Set the bias to 30mv and went to work on the preamp/tone board. I know I’ll catch flack for this part but I replaced all of the 10uf signal path catalytic capacitors with (2) 4.7uf capacitors in parallel. There was 2 reasons for this 1: the 10uf would have been too tall and would not have let the board fit back in and also 4.7uf was all I had and at $30 for 50 of them it was considerably cheaper than using 10uf’s (there’s something like 12-14 10uf caps in the signal path). Replaced the monster 8000uf main filter capacitor with 3 4700uf caps, replaced the output capacitors with some nichicon gold caps, Cleaned all the controls and reassembled it. Hooked it up to my realistic minimus 7 test speakers and wow!
I have it playing though my rebuilt Jensen 700xl speakers now. I’m not joking that this is one of, if not the best sounding solid state receiver I’ve heard. It should be noted that I prefer tube receivers but this thing is close to my fisher x-100-b in warmth.
