HI, I have 2 RFZ-V781 units that I serviced, now both units are working but there's a 1.2 db difference between the preamps.
I would like to calibrate the three trimmers (R102, R114 and R129).
According to the manual (with google translate): "The power supply circuit contains a pnp, transistor (T 113) as a filter resistor, so that the necessary ground voltage reduction is achieved in the non-earthed connection line. R129 is used to set the operating voltage (- 22 V to both)."
So I set the voltage on the negative side of C121 as close as possible to -22V (-22.45 was the lowest voltage I managed to get from the trimmer).
Now what about R102 and R114?
In all the schematics I found the voltages values on the bases of T102 and T107 are none readable.
I tried to search on the manual but couldn't find any reference to the base voltages.
In reality, the base voltage of T102 varies between -22 to -14 V and the base voltage of T107 varies between -22 to -17 V.
Maybe someone knows what should be the correct voltages?
I would like to calibrate the three trimmers (R102, R114 and R129).
According to the manual (with google translate): "The power supply circuit contains a pnp, transistor (T 113) as a filter resistor, so that the necessary ground voltage reduction is achieved in the non-earthed connection line. R129 is used to set the operating voltage (- 22 V to both)."
So I set the voltage on the negative side of C121 as close as possible to -22V (-22.45 was the lowest voltage I managed to get from the trimmer).
Now what about R102 and R114?
In all the schematics I found the voltages values on the bases of T102 and T107 are none readable.
I tried to search on the manual but couldn't find any reference to the base voltages.
In reality, the base voltage of T102 varies between -22 to -14 V and the base voltage of T107 varies between -22 to -17 V.
Maybe someone knows what should be the correct voltages?
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