Thank you your reply, Michael.
I suspected something of the sort and wondered if perhaps there was a dirty contact that may only need cleaning.
I would appreciate your help in locating a local concern that could help.
I live in Waterlooville, Hampshire, about 15 miles north of Portsmouth,
and reasonably close to Fareham and Havant.
A telephone number or Email address would help considerably, if you can advise me please.
Thank you, Michael.
I know of Nevada Music, not too far from me.
I purchased an amplifier there a couple of years ago.
I shall enquire about repairs.