In an earlier video i described how to localize defects in transistor radios without measuring equipment. Since i made that video i have repaired this little radio.
The IF coils were defective. The core had gotten stuck to the windings. Heating up didn't help. Upon turning, it broke completely.
I swapped it with another IF coil.
The other IF filter had the same issue. The core was still usable, i could fixate it with candle wax in the correct, well tuned position.
You don't usually re-tune the IF, but many years ago i already figured out these were out of tune, so i had to take the risk.
Right now it still has several issues:
Potentially bad decoupling electrolytics causing whistling sounds
No shielding of the IF cans i just installed - will solve that later.
A short circuit in the tuning cap
Bad alignment of the oscillator - radio stations not on the right spot on the dial
Almost no shortwave reception.
14 окт 2024
