Vintage Cassette Radio Recorder – National Panasonic RQ
432S schematic, layout and dial cord setting.
The main fault that can occur to this set is the
tuning drift occurs when climate changes. The
inductance of TR54 and or TR56 may change. Replace them if this type of fault occurs. If you blow some hot air over these coils, it may work properly, the fault will come back after some time. There is no remedy than changing them.
At the amplifier stage, C19 and C20 [capacitors
connected between collector base of the output transistors] may get leak. Resulting distorted audio output. The company have used steroflex capacitors
there. I’ve replaced both of them with
disc ceramic [250VDC] type, and going fine.
The C34 [1000MFD-10V] should be checked for its
capacitance. It is best to replace
it. Sound distortion can occur if this
capacitor is damaged.
C32 [220MFD 10V] can also be problematic. Replace it with a new one.
I own this model set, which bought at mid of 70s, I
presume, is working fine till time.
There is no more problems can occur to this set.
Amplifier section schematic
