Tried my head with another cab and tried my cab with another head. Nothing. Bugger :(
Right, I guess I'm amp shopping in the new year. Always wanted an Orange, guess I can get one now :)
Paddy
If you open your cab you should be able to test if the speakers are ok by using a cheap multimeter.
the speakers, depending on how they are wired, might cause a problem with fault finding.
but a good speaker has a + to - resistance similar to the impedance of the speaker. I think i used to get 6 or 7ohms from an 8ohm speaker. The different reading is just because impedance is frequency dependent and not like standard passive resistance. I think!
that would you should be able to find what has blown, or if it is a wiring issue.
as for the head.
As for the amp... plugging in the FX return is usually a good way to test only the power amp. might be loud. depends if a master vol is pre or post loop.
if you get sounds there then the issue is in the preamp. If you get nothing still... then it is the power amp.
You can check transformers using a multimeter. checking resistance on the primary of the OT by measuring right across the winds, and then each side to the common. each side to the common should be equal i think. If you have a short or really weird reading it is a sign your OT is messed up. It isn't a very accurate or 'be all, end all' test and it is never safe to poke around in amps, but it is something I read about once when I needed to check one.