JVC KD-X2 cassette deck noisy channel

[PeterMac63]

I picked up a decent Dolby C deck by JVC, the KD-X2. by its design I would say mid to late 80's (?).
When it plays properly it sounds very good, but it has an intermittent but persistent issue with one channel.
About half the time this terrible loud tone comes out of the left channel. When this happens the peak indicator on the left channel is at maximum and a very loud tone, possibly 50 or 60 hz (?) comes out of the left channel. Speaker damaging levels I would guess, if the volume was up quarter way. You can see the bass cone pumping in and out quite vigorously even at about 10%. Whilst this happens the right channel seems to go very quiet.
Then it will fade out and both channels will play normally, at which point it all sounds very good. This may continue for a few minutes then the noise will be back.
Weirdly this morning it seems to be behaving itself! So here is a photo of it in a good mood.
Is this likely to be a failed component or something else. Is it worth fixing? Any ideas would be appreciated, cheers.

 

[Max Headroom]

Record/Playback switch contacts go noisy with no usage.
Solution is to operate this switch....ie Record mode, Stop, Rec, stop 20 times and you should be ok.



Dan.

 

[JonSnell Electronic]

Spray the switch, whilst manually operating it, with contact cleaner.

 

[PeterMac63]

Well, I shouldn't complain, but it hasn't gone wrong all day! Weird....

....But should it do it again I will try these things. Cheers.

 

[Mooly]

Definitely clean the switch as described, its a decades old stock fault... and a word of warning... don't have a tape with anything you want in place while doing this because operating the switch will turn on the record/erase circuitry and wipe the tape if you happened to have it playing.

 

[PeterMac63]

Cheers Mooly, I will do that.

This was from a house clearance and probably hadn't seen action for years. It has maybe just taken a wee while to resurrect itself. Still going fine at present!