hello, i have a 2230 with a bad amp, i already change all the bad transistors and other parts, by the way all the transistors except the input one was toasted, both 1n60 diodes, sv-3a diode, emitter resistors, and at least 7 miscelaneus resistors were toasted or open, all electrolitcs are new too. the problem now is bias, no more than 2mv across both emiters resistors with pot at maximun obtained and sound is distorted. as a note the voltage at rectifier bridge is 74 volts, against the 66.5 that schematic says. here in Mexico the mains are 125~127 volts, so i adjust my variac to 120 volts output and the rectifier voltage drop to aprox 70v, still high i think. the other channel sounds good even with the 70-74v input.
transistors used bought at Mouser
mj21194
ksc945c
ksa733c
2n3440
2n5416
rubycon caps
vishay emiter resistors
the only cap still original in the bad channel is the coupling capacitor.
about pcb amp voltages: some low, some high against schematic ones.
any opinion? Any help will be really appreciated.
best regards!
Pio
transistors used bought at Mouser
mj21194
ksc945c
ksa733c
2n3440
2n5416
rubycon caps
vishay emiter resistors
the only cap still original in the bad channel is the coupling capacitor.
about pcb amp voltages: some low, some high against schematic ones.
any opinion? Any help will be really appreciated.
best regards!
Pio
Last edited:
