Re: My Orange OR15 head just crapped out. Need help
Speaker ? Although i'll assume you have checked that, and substitued every sonic link (guitar, cable on the input side, speaker lead, speaker cab on the output side). Does that amp feature a standby switch ? If you turn all the amps controls up without playing, can you hear any hiss or humm through the speaker ?
When an amp itself seems to be the culprit, but the power light comes on and the tubes glow, that can often mean there is a break in the signal path somewhere in the amp's circuitry. (some amps may have a secondary fuse, in the high-DC voltage line ... if that fuse blows, there will be no sound, but the heaters and power lamp will still light up). If the amp has an effects loop, you can try plugging a jack plug in and out of the sockets a few times, or even linking the loop output and return input with a short guitar cable.