M70 left channel not working with cassette, but OK with radio

[nechurech]

Hey, guys. I'm new here, I've only had my M70 for a couple of weeks (been enjoying every minute) and I ran into a problem today.

While listening to a cassette, suddenly the left channel stopped working. Actually, I thought the speaker died, but then I tried playing the radio, just to be sure. Radio plays strong and without problems, i switched from left to right, everything was OK.

With my inexistent electrical knowledge, I'm asking for help. Could it be something concerning the stereo signal in the cassette player? The cassette I played before left channel "died" had a very low frequency bass part, that shouldn't be a problem and I played that cassette before, a couple of times. I just thought I'd mention that, although it might not be important. VU meter doesn't work on the left channel, but when I play the radio - yes, you guessed it, works without problems. Even moves when I turn the boombox on, so the meter is working, the speaker is working, but NOT while a cassette is playing.

Also, I'd like to mention that I've cleaned the head, pinch roller and capstan a week or so ago, so that shouldn't be the problem.

Any help appreciated...

 

[Atomtan]

My money would be to clean the record bars first, but I am yet to open up my M70. There are some excellent videos on Youtube on the Teddy Hashee channel where he fully services and overhauls an M70 (it runs for nearly 2 hours). I have to do mine in the near future.

 

[BoomboxLover48]

Like Atomtan mentioned it could be a contact problem that is related to the record switch.
A full switch cleaning is needed for the M70.

Use a blank tape and press rec/play, stop, and repeat it a couple of times. Remove the tape and see you hear from both channels. In some cases it will work if it related to record switch cleaning. Try it and see!

 

[Transistorized]

I would be willing to bet it's the Function selector switch. They get dirty and can drop a channel on a selected Function. Sometimes, if it is a dirty record bar, you can put the deck into record a few times to work the switch and not even have to take it apart.

 

[JVC Floyd]

I had the same problem on several boom boxes and believe it or not it turned out being the playback head and or bad soldered joints on the playback head.

 

[JVC Floyd]

If it records on both channels then most likely if it only plays back on one channel it's the playback head.

 

[nechurech]

So, I just wanted to share what happened in the end... turns out my boombox was ripe to be serviced. My repair shop told me that a preamp for the cassette playback basically bursted, probably because of age. Something like that, if I remember correctly... They were able to fix it, so it can be taken care off. Anyway, all good now, M70 is making my neighbours madder and madder by each passing day.