Is the transistor shorted?
Do the drivers appear to be installed properly?
With the black probe on the emitter, what's the DC voltage on the base and collector of the equivalent of the Q105 and Q106?
Do the drivers appear to be installed properly?
With the black probe on the emitter, what's the DC voltage on the base and collector of the equivalent of the Q105 and Q106?
B-E 0v up to 0.3v depending on which transistor..
E-V 50v rail voltage, no transistors are shorted, no diode shorted.
E-V 50v rail voltage, no transistors are shorted, no diode shorted.
It doesn't appear that the differential amplifier has enough bias current.
For the 4 100 ohm resistors connected to the emitters of the differential amplifier transistors, what is the voltage across the individual resistors?
For the 4 100 ohm resistors connected to the emitters of the differential amplifier transistors, what is the voltage across the individual resistors?
Previously, there was voltage across the resistors that fed voltage to those transistors. One resistors was connected to the 15v supply and the other resistor in series had about 5.5v across it. Do you still have that voltage across those resistors?
No, I don't have this voltage across, only at the input at these resistors. It seems, that the 15v very easy break down..
Are you saying that there is no longer the ±15v supply voltage?
What's the voltage measured across R160, 160A, 161 and 161A if you still have ±15v?
What's the voltage measured across R160, 160A, 161 and 161A if you still have ±15v?
Yes, there is no voltage drop. But if I remove all the smd transistor, the 15v is present at the solder pins from the transistor.
There is 1,7ma flowing through R160. That has to be coming from somewhere. How can you have 0.000v across the 100 ohm resistors if half of the 1,7ma has to be flowing through them?
Yes, it is strange. If I remove the transistor, I have the full 15v there. If I reconnect one, the voltage drops to 0.6v but no voltage across the 100 ohm resistor. Maybe when the transistor get over the 0.6v,it opens and the transistor behind will drop the voltage.. I will remove the other stages.
Removed the 100 ohm resistors, input at the resistor +15.8V, the output of the resistor connected to the transistor is - 16.9V
Are the 100 ohm resistors within tolerance?
When you break the connections by removing components, the voltage goes back to approximately the supply voltage because there is essentially no current flow.
When you break the connections by removing components, the voltage goes back to approximately the supply voltage because there is essentially no current flow.
The resistors are in tolerance. I removed first all other transistors and caps, but was still the same problem. Only the two smd resistors in circuit,. First when I removed the resistors, the voltage goes normal.
If you reduce the value of resistors 160A and 161A, you will increase the bias current through the differential amp and likely through the entire output stage. If you do this, be careful, it could cause significant idle current.
I bridged the resistor allready in the beginning, but the voltage drop at the transistor was still to much, nothing happened. I don't know, maybe the transistors are likely damaged, will try to exchange them