Dritan
New Member
Hi. A week ago I got an old Pioneer SA-8100 amplifier. Tested it and it worked for few moments and the protection circuit did its job, several time thus I decided to go further and repair it.
I recapped the power supply and the power amp.
I have changed the transistors:
AWR-030:
q1 - TIP122
q3 - C2383
AWH-022:
q1-q4 - bc557
changed trimmer resistors VR1 to VR4 and electrolytic capacitors.
Yet the voltages are offset.
I started to measure the AC output of the transformer on the power supply board, and got these values:
pin 1: 7.7 V
pin 2: 7.7 V
pin 6: 30.0 V
pin 7: 41.5 V
pin 8: 41.5 V
Are this figures correct?
The transformer is ATT-105
Meanwhile the DC values are;
pin 4: - 42.2 v
pin 5: + 42.2 v
pin 9: + 56.7 v
pin 10: 0.0 v
pin 11: 0.0 v
pin 12: - 52.5 v
pin 13: -34.8 v
pin 14: -31.2 v
pin 15: - 0.07 v
pin 16: +0.06 v
pin 17: -0.93 v
pin 18: -0.42 v
pin 19: +3.5 v
Thank you in advance.
I recapped the power supply and the power amp.
I have changed the transistors:
AWR-030:
q1 - TIP122
q3 - C2383
AWH-022:
q1-q4 - bc557
changed trimmer resistors VR1 to VR4 and electrolytic capacitors.
Yet the voltages are offset.
I started to measure the AC output of the transformer on the power supply board, and got these values:
pin 1: 7.7 V
pin 2: 7.7 V
pin 6: 30.0 V
pin 7: 41.5 V
pin 8: 41.5 V
Are this figures correct?
The transformer is ATT-105
Meanwhile the DC values are;
pin 4: - 42.2 v
pin 5: + 42.2 v
pin 9: + 56.7 v
pin 10: 0.0 v
pin 11: 0.0 v
pin 12: - 52.5 v
pin 13: -34.8 v
pin 14: -31.2 v
pin 15: - 0.07 v
pin 16: +0.06 v
pin 17: -0.93 v
pin 18: -0.42 v
pin 19: +3.5 v
Thank you in advance.