You are right. After replacing C212 470uF 10V capacitor on the OL-2 board, it does not trip.
Hans,
I need again your help with my right amp. The problem is a bit similar than in my post #356.
One day I turned the amp on and I heard loud hum from the transformers(I think) and no sound from the right channel.
I have connected the 100R resistors in the VCC unregs and there is 85V drop in the resistors even if the pot R124 is completely open. Now I have only 4 pairs of output transistors connected and all the voltages over the 10ohm base resistors and the 0.22 resistors looks normal. This time when I short the WH.1 and WH.5 the voltage over the 100R resistors is only around 1V.
I can provide you more data...
I need again your help with my right amp. The problem is a bit similar than in my post #356.
One day I turned the amp on and I heard loud hum from the transformers(I think) and no sound from the right channel.
I have connected the 100R resistors in the VCC unregs and there is 85V drop in the resistors even if the pot R124 is completely open. Now I have only 4 pairs of output transistors connected and all the voltages over the 10ohm base resistors and the 0.22 resistors looks normal. This time when I short the WH.1 and WH.5 the voltage over the 100R resistors is only around 1V.
I can provide you more data...
Here are some data that you might be interested:
I have now 8 TO3 output transistors connected instead of all 12 pcs.
10ohm base resistors:
+(mV) -(mV)
30 18
29 18
30 18
31 19
0.22ohm emitter resistors:
+(mV) -(mV)
44 45
44 44
44 47
47 44
If you need any other data I will measure.
- voltage drop in the 100ohm resistors in the VCC unreg lines: 85V in both lines(pot R124 fully open).
- R50 = +0.8/-0.8(V)
- R45 = +1.49/1.53(V)
I have now 8 TO3 output transistors connected instead of all 12 pcs.
10ohm base resistors:
+(mV) -(mV)
30 18
29 18
30 18
31 19
0.22ohm emitter resistors:
+(mV) -(mV)
44 45
44 44
44 47
47 44
If you need any other data I will measure.
So, when shorting WH.1 to WH.5 there is almost no current flowing through the 100R resistors.
To be honest, I don´t know what R45 and R50 are, but anyhow, it seems that the problem must be something in the output stage but not in the 8 output transistors.
To start with, I would like to know the output voltage with the two 100R resistors still in place.
The next thing to be measured is how much current is flowing from WH.1 to WH.5 when replacing the short by you multimeter.
This should be between 16 and 18mA.
Hans
To be honest, I don´t know what R45 and R50 are, but anyhow, it seems that the problem must be something in the output stage but not in the 8 output transistors.
To start with, I would like to know the output voltage with the two 100R resistors still in place.
The next thing to be measured is how much current is flowing from WH.1 to WH.5 when replacing the short by you multimeter.
This should be between 16 and 18mA.
Hans
O.k. results so far.
The voltage amp seems to be working allright and so are your 8 output transistors.
Now the next step I would like you to do is to put a diode between WH.1 and WH.5 and measure the voltages over the two 100R resistors that you inserted.
When this still shows a very low current flow, add a second diode and meausure again.
Depending on the outcome we can take the next steps.
Hans
The voltage amp seems to be working allright and so are your 8 output transistors.
Now the next step I would like you to do is to put a diode between WH.1 and WH.5 and measure the voltages over the two 100R resistors that you inserted.
When this still shows a very low current flow, add a second diode and meausure again.
Depending on the outcome we can take the next steps.
Hans