Aiwa CS-M1 No R-Channel but only on speakers

Hi,
So, like in the title, I'm having this peculiar issue. The little Aiwa will play on both speakers in radio mode, but on the microcassette, it only plays through the left speaker. What confuses me is that it plays both channels just fine on headphones.
Any ideas what might be the problem?

Edit: It sometimes played only the left channel on the radio too, but that was a dirty radio/tape switch. Cleaning it did not fix this issue.
Edit 2: Just really dirty radio/tape switch, after working it for 15 minutes it started to work on both speakers again.

Problem solved.

 

Yes, I got it less than a month ago, it's a red one.
Took a bit of a gamble with it - the seller had no feedback at all. I paid $50 for it, listed as totally dead.
Someone had been taking it to the beach and the volume control was not conducting at all, making it seem "dead".

Ironically enough, now the left channel is gone. But it's not the switch. Something in the amplifier section went open. I narrowed it down to 4 capacitors, will replace them on Monday.

 

Ah, well, it's not like it was a steal - I think it was worth just about 50.
It needs a complete recap, and I had to do a lot to get the mechanism working. It has a split forward/reverse gear.
Cosmetically it's far from perfect too. Lots of wear. Looks good from a few inches away though.

 

Ha, after a while the left channel stopped working. Nothing to do with switches - the radio experienced a widespread capacitor failure. I had to recap the entire amplifier section, 22 capacitors or so. It works well now, but I really don't recommend these for anything other than putting them on a shelf - terrible (for Japanese standards) quality of electronics, Aiwa really dropped the ball with this one. I've never seen a Sony do this, even their cheapest Walkman models from the 80's held up way better than this radio.