Found this small radio at the local flea market:
I initially thought it is a radio by what appeared to be large tuning knob occupying its face. Getting closer, it was just a label – but turning it around I spotted the Volume button and the Tuning knob.
I like interesting / atypical designs, measuring 5.5cm in all directions. It didn’t look modern – no FM band, only AM. Having a look inside, I spotted small transformers and a mix of Si transistors with Ge transistors for output. Hehee .. I bought it.
Inside Photos
Here are some photos with the insides of the radio. Everything looks cramped, especially with the gray capacitor riding on top of the transistor! Ha, never saw this before 🙂
Diagnosis
I plugged a battery in, but it did not produce any sound.
These radios, while small and cute – are annoying to work on. Plastic is brittle and if you pull too hard you risk cracking something. Not to mention lots of glue. And very thin wires. Any screw taken out risks stripping the screw-hole. Etc.
I attached a 1.5V power supply to it, and again, dead silent. Still, 11mA draw at 1.5V but still no sound ? The tiny hooks I was using kept unclipping themselves, me trying to reattach them – all of a sudden, very loud hiss! WOW. Then no sound again.
After a bit of looking around …
… one of the wires was not making contact with the speaker.
Fix
The fix was to resolder the wire, paying LOTS of attention to not touch the plastic around with the hot soldering iron. I did not.
Initially I tried just resoldering in place, after applying flux. But it wasn’t taking solder properly ?! A big blob was formed, instead of melting, it was just hanging on the lip of the connector. I stopped since I didn’t want melted solder to fall onto the speaker – and I took it out. With the wire out, I tinned it, made it in a little hook and soldered back. Then it soldered fine.
The radio now works fine (watch the volume please, it gets loud):
I also gave it a good scrub:
While cleaning, I spotted that one of the black “dots” on the side of 6 dots was glued – maybe it got loose and somebody did take care of it in the past ? No other dots have these marks.
What they didn’t do (or maybe it cracked later) is that the battery lid had misses one of the plastic protrusions anchoring it on the case. It still holds though:
Finally, somebody also has decided to cut the “battery negative” spring. I believe the reason is that the standard AA battery is too big for the radio. Even with shorter spring, it is still hard to the battery in as it deforms the case:
A cute little radio that I can’t even seem to find on RadioMuseum website. It feels like I’m writing a small page of history 🙂
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