Greetings,
I have an Holfi integra amplifier, ver.1.1, I bought it thinking it would be an easy fix, but I didn´t expect to find every transistor on the power amp circuit replaced.
Can´t find any documentation online, I drawn a schematic to help me repair it. The output transistors were shorted so I replaced them, still it had full DC on the ouput, then noticed the first transistor (T1) was a 2sc2240GR and it needed more gain to get the proper bias, so I got a 2sc2240BL and solved the problem.
Now the only problem I have is no bias current on the output transistors and I find it weird to see a darlington BC879 as vbe multiplier (T6) that measures as a PNP instead of a NPN, and the pinout doesn´t seem to match the circuit board.
Does anyone know which is the original transistor? Is it viable to replace the base resistors and the transistor to a single npn instead?
Thanks.
I have an Holfi integra amplifier, ver.1.1, I bought it thinking it would be an easy fix, but I didn´t expect to find every transistor on the power amp circuit replaced.
Can´t find any documentation online, I drawn a schematic to help me repair it. The output transistors were shorted so I replaced them, still it had full DC on the ouput, then noticed the first transistor (T1) was a 2sc2240GR and it needed more gain to get the proper bias, so I got a 2sc2240BL and solved the problem.
Now the only problem I have is no bias current on the output transistors and I find it weird to see a darlington BC879 as vbe multiplier (T6) that measures as a PNP instead of a NPN, and the pinout doesn´t seem to match the circuit board.
Does anyone know which is the original transistor? Is it viable to replace the base resistors and the transistor to a single npn instead?
Thanks.