If you measure directly across the terminals of R110, do you see a shift of DC that corresponds to the DC you see across the output?
Wire disconected, Mainboard Pin against ground 1.35V
Preamp Bord Pin against ground 3.8V
If the wire is Connected, 0.5V increasing,Same Speed as dc Offset is dropping. When 3.6V ist reached,DC Offset is 0V
Preamp Bord Pin against ground 3.8V
If the wire is Connected, 0.5V increasing,Same Speed as dc Offset is dropping. When 3.6V ist reached,DC Offset is 0V
This is what I want to know... Is the voltage that's driving DCV to R108 coming from the preamp board?
If you leave the black wire disconnected and short R108 to ground (before applying power) do you again get voltage building on R108?
If you leave the black wire disconnected and short R108 to ground (before applying power) do you again get voltage building on R108?
Checked again,Its negative Voltage. If i ground it,it doesnt Change anything. If black wire disconected,i got 0.12v at r108. DC Offset is 0V.
Connect the black wire,it seems,that a cap ist getting charged, Voltage goes more negative,until 3.6V, and DC Offset is 0V again. If i Switch Off Power supply,it needs a few minutes,until DC at R108 is 0V again.
Connect the black wire,it seems,that a cap ist getting charged, Voltage goes more negative,until 3.6V, and DC Offset is 0V again. If i Switch Off Power supply,it needs a few minutes,until DC at R108 is 0V again.
What's the resistance across C40?
Are you 100% sure that R108 (when black wire is connected) is connected to Q24?
Are you 100% sure that R108 (when black wire is connected) is connected to Q24?
Rechecked, Connection between R108 and Q24. Cant locate c40 on the preamp Board. C41 is the Last one
That means that I won't be able to help much. You need to find the source of DC on the preamp board. Do you have an op-amp with excessive DC on its output?
Yes,i found one with 10V DC,removed that one,but Problem persits. Changed the OP amp with abother OP amp,but still the same..
Yes, after i changed the op amp, its the same 10VDC at the op amp. Tomorrow i will give you the details.
DCV on all terminals of that op-amp. copy and paste and fill in:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
U25 JRC 2068
Pin 1: 0V
Pin 2: 0V
Pin 3: 0V
Pin 4: -14.7V
Pin 5: +2V
Pin 6: +2V
Pin 7: +10.2V
Pin 8: +14.6V
Pin 1: 0V
Pin 2: 0V
Pin 3: 0V
Pin 4: -14.7V
Pin 5: +2V
Pin 6: +2V
Pin 7: +10.2V
Pin 8: +14.6V
2.05
2.05
What Transistor should be Q24? IT hast been replaced from another technician,and cant read the markings
2.05
What Transistor should be Q24? IT hast been replaced from another technician,and cant read the markings
It appears the op-amp is operating normally. What's feeding pin 5 of this op-amp.
I have it as a MMBFJ111 but my information and your board are different.
I have it as a MMBFJ111 but my information and your board are different.