I have an Orange Dual Terror valve amp. Its about 4 years old but has sat pretty much unused since covid started (i've been playing acoustic instead).
I've now discovered the amp isnt working. Ive given it a bit of a clean (it wasnt that dusty as was left under a cover) and a few squirts of contact cleaner but to no avail. Every now and then i get a bust of sound for a second then silence again. If i turn everything up i can hear it working but as if on mute.
Any suggestions before i have to take it in for what i expect will be an expensive service??
fuses ok ? my marshall has 2 at the back of the case.
Just checking the basics. Have you tried it with a different lead, different guitar?
what happens if you twiddle the knobs while making sound not cracking or anything?
If i turn everything up i can hear it working but as if on mute.
I'd guess part of the power section has gone pop - I.e. a tube. Or maybe as above a fuse has gone.
I don't think that amp has a separate pre-amp output (like for 4 cable method) so you can't test that separately.
I'm not sure how much home diagnostics is feasible / sensible with these. I'd just take it to get fixed by someone who knows what they are doing!
I’d just take it to get fixed by someone who knows what they are doing!
Yep, think thats what will happen, i'm just trying to rule out the obvious first.
If it has an effects loop, trying going in the effects return. Depending on how it's laid out, this might bypass the preamp and could indicate where the problems lie.
The factory for their UK-made stuff is in Borehamwood, I imagine that's where it'll have to go, at least it won't have to be posted to the back of beyond and incur import/export nonsense.
like this from the manual
If they're like a Marshall JCM anyone who can read a multimeter can set the bias. I'd buy one each of the tube types and swap them out one by one before taking it to a specialist.
Thanks everyone. I've managed to fix it. It was corrosion in the speaker cab input. A bit of sandpaper and contact cleaner got it sorted in a way that wiggling / swapping cables didn't.
Its the obvious things that evade me most often :-/
Nice one. At least you found the problem without spending a fortune, unlike me who sent his bass amp head away to the approved repairer who, after charging £££ couldn’t find anything wrong with it…
Ouch!
Yup! They decided it was a problem with the pots so replaced them all at cost of £125 parts and labour, plus the diagnostic fee, plus the labour for testing, plus the insured shipping back, I didn't seem much change from £270.
I could have bought a second-hand replacement head for less than that!