Hello can any trace buffs give me an idea where to start? I managed to get a GP7 SM head and a Trace 15 inch cab for 40 quid,only trouble is the head lights up etc and it seems like the transformer inside powers up but no sound,i noticed when i switch it on the fan does not start but if i push it,the fan starts.The inside is immaculate and it was working up until a few weeks ago,(its my drummers mums old amp). I know a bit about soldering and components but not loads. Is there a common fault on these amps? I would appreciate any ideas,I will award a large bag of haribo kiddies mix to the person who provides a solution,hope you are all well.