Here are my readings hoping to have some enlightening feedback
Can you measure the voltage at the emitter of Q27?
Q27 emitter -13.13
Q28 emitter +14V
The collectors of these should be near zero but they measure 14v
Allready replaced Q28 and Q15 without any changes
You have two voltages written beside TP3 and TP4. Which is the actual one in each case?
Andrew
They are the 220 ohm resistors that drop the main +/- 24V rail voltage to the "target" +/- 12V at TP3 and TP4. These nodes are also connected to C14 and C15, respectively.
Yes, this seems fine. So something else is causing the current imbalance between the two polarities of the circuit. Because those voltages after the first 220 ohm dropping resistors are very close in magnitude (18.8V, -18.6V), if the current draw was identical in both polarities the values at TP3 and TP4 would be nearly identical. It's actually the current drawn by the positive branch that is slightly low from what it "should" be.
There are a couple of ideas now:
Measure the voltage at the opposite side of each component connected to TP3 and TP4 (emitters of Q4 and Q5 and the non-TP sides of R14, R37, R36, R38, R39, R30).
OR, if you're willing you can lift one side of R34 and insert a ~20 ohm resistor in series with it. This will drop the voltage at TP4 another 0.5V and make sure that Q27 is conducting. If we now have a low DC offset at the input to RIAA we can work through what is the cause of the current imbalance.
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