Trk 8080 squeal on left channel

I have been restoring this over summer. I had hoped I had cracked all of its issues but on pressing play on the tape deck, you get a loud squeal from the left channel which shows well on the vu meter. Sometimes it settles down after a few moments, sometimes it stays. I have tried everything and suspect it could be a bad capacitor.

I'm not sure where to go next with this, any help gratefully received.

Most of the times, a squeal indicates a dirty record bar. If you don't know what it looks like, see this topic:

https://boomboxery.com/forum/index.php/topic/28289-record-switch-bar-example/

I would use a non-residue contact cleaner. DeOxit has both regular cleaner and cleaner with lubricant. Just go with a regular cleaner.

Can also be the volume pot or the Mic inputs. Does it happen on all sources?

Thanks for the advice on this, I will try and get it apart again in the coming weeks and post an update.

To finish this thread, I got the unit apart this weekend with little hope as I felt I had sort of covered everything before....

However, I purchased some Wynns pure contact cleaner and drenched the record bar and volume pot, more out of frustration with a box with 40+ hours in it, rather than good technical approach. Well, to my surprise, after much working the record bar 'regurgitated' a long, snotty piece of fluff. (This was a box that had been full of woolen carpet fluff). And then to my greater surprise, the bloody thing worked perfectly and continues to do so.....Not the prettiest box in the village, but interesting to work on (without being a nightmare) and in the end, came up very well.

Thanks again for the advice and guidance.

Good stuff, another restored, enjoy!!!