pakko
Member
Hey everybody!
I just finished reworking a rare Technics/N.P. amp from 1969. A National Panasonic SU-50A which should be the first transistor amp from Technics at that time.
The amp is running very good and the sound is surprisingly nice and smooth.
I recapped the whole unit with new caps incl. the main caps.
Last step now is to adjust the old fellow.
The Service Manual gives me only informations for the Bias Adjust - but there are two more trimmer I still did not touch. Maybe someone here give me a hint how this works!
We have three trimmer on the power amp board.
I think RV 19, 20 are for the Bias Adjust to 10mV over the Emitter Resistor.
RV 15, 16 are at the input of the Power amp and
RV17, 18 are after the two input transistors.
So - what and how can I adjust RV 15 - 18?
Thank you....
Here are the files from the SM:
I just finished reworking a rare Technics/N.P. amp from 1969. A National Panasonic SU-50A which should be the first transistor amp from Technics at that time.
The amp is running very good and the sound is surprisingly nice and smooth.
I recapped the whole unit with new caps incl. the main caps.
Last step now is to adjust the old fellow.
The Service Manual gives me only informations for the Bias Adjust - but there are two more trimmer I still did not touch. Maybe someone here give me a hint how this works!
We have three trimmer on the power amp board.
I think RV 19, 20 are for the Bias Adjust to 10mV over the Emitter Resistor.
RV 15, 16 are at the input of the Power amp and
RV17, 18 are after the two input transistors.
So - what and how can I adjust RV 15 - 18?
Thank you....
Here are the files from the SM: