What is the DC voltage on all 3 legs of Q905 and Q906? Place the black meter probe on the right positive speaker terminal. Place the red meter probe on the point where you need to measure the voltage.
With the black probe in -ve speaker connection,
905: (left to right) 62v 3.5mv 62v
906: -66v -0.93v -66v
Isn't it like 5am where you are? 😱
905: (left to right) 62v 3.5mv 62v
906: -66v -0.93v -66v
Isn't it like 5am where you are? 😱
Last edited:
Almost 5am. I have no schedule. I live on 25-26 hour days so I'm up all times of the day and night.
DC voltage across R905 and R906?
DC voltage across R905 and R906?
hmmm... close...
68kohm and 66kohm
(I think they should be 66kohm)
Blue, Blue, orange, gold.
6 6 000 5% yeah?
68kohm and 66kohm
(I think they should be 66kohm)
Blue, Blue, orange, gold.
6 6 000 5% yeah?
That's OK. They should be blue, gray, orange, gold according to the diagram. If they're blue, blue..., it could be a revision.
What is the DC voltage on all three terminals of Q901 and Q903? Place the black meter probe on the right positive speaker terminal.
What is the DC voltage on all three terminals of Q901 and Q903? Place the black meter probe on the right positive speaker terminal.
It was grey, just poor light was making me think it was blue 😱.
The values:
901: -0.63v, 62v, -11mv
903: 0.57, -65v, -11mv
With the -ve probe on the +ve speaker terminal.
The values:
901: -0.63v, 62v, -11mv
903: 0.57, -65v, -11mv
With the -ve probe on the +ve speaker terminal.
It would appear that at least 2 of the transistors Q901-Q904 are defective (although it's very rare for these to fail). Pull them and check them very carefully.
I tested the Q's on the board, i daren't remove them, unless i'm sure.
There were no shorts, but I couldn't prove there was no 'open's'
I found however that Q909 and Q111 were shorted base to emmiter, both directions...
Is that correct?
There were no shorts, but I couldn't prove there was no 'open's'
I found however that Q909 and Q111 were shorted base to emmiter, both directions...
Is that correct?
Do you mean Q911?
If either Q910 or Q911 is shorted B-E, both will appear to be shorted B-E. They shouldn't appear to be shorted. Remove them and check them out of the circuit.
If either Q910 or Q911 is shorted B-E, both will appear to be shorted B-E. They shouldn't appear to be shorted. Remove them and check them out of the circuit.
Ok, Q911 is out. Now across the B-E of Q909 I get 22kohm and rising fast.
Across B-E of Q911 (A1015) I get 0.3ohm (a short?)
I'll replace Q911.
Across B-E of Q911 (A1015) I get 0.3ohm (a short?)
I'll replace Q911.
- Status
- Not open for further replies.