Hi Vaux,
Thank you for the suggestion.
I don't think alignment and cleanliness of the ACE head is the issue here. It's spotless and the alignment is bang on, as when it was behaving I made a test recording and it played back beautifully on my other vhs vcrs without tracking adjustments. Also I played back a genuine JVC alignment tape with the tracking at centre click and all was perfect. I'm thinking it's definitely an electrical fault somewhere, but where I don't know as I don't have a scope or any other test equipment to check anything.
It'll probably get sent off to be looked over professionally.
Thanks again for the suggestion though
Ps) Have you found a spare working audio board for a 3V36 amongst your spares yet that you'd like to sell?
Cheers,
Richard.