SVT-CL: Another one for the guru :-)

[TimmyP1955]

It came in with the mains fuse blown. I replaced the fuse, pulled the 6550s, and powered it up: No heaters in the 12AU7s - the 1.5A filament fuse on the AC inlet board was blown (which puzzles me). Replaced that and got the heaters back. But: The pilot light comes on for a bit, then fades out. The filaments are still aglo, and the red bias LEDs are glowing - maybe this is normal and I just never noticed? (6550s are still out.)

I'll dive back in tomorrow, but in the mean time....

[drewl]

check the cables/wiring harness to the preamp.

Look for any bad PC board connections or possible shorts, especially the filament lines.

I'm no guru, but have done my fair share of these.

[The Dude]

The power light not going green is normally an indication of a power tube failure, so if you don't have the output tubes installed, I would think that would be a normal response. If both the mains and filament fuses were blown, the most likely cause is a shorted or intermittently shorted power tube. If you have a tube tester, see if that will tell you which tube or tubes is shorted. If not, replace them all with new or install the old tubes separately to see which one causes the problem.

[TimmyP1955]

It's the red light that comes on and then fades out - with the amp in standby.

The filament fuse covers only the 12A*7 heaters - and maybe only the ones in the amp section (I forget). All seems well there now.