F-100 Troubles!

[jkornel]

Hope someone can help, I have gigs next weekend and need to get my amp working!

My F-100 head started acting funny last rehearsal. I was playing and all of a sudden my volume dropped like someone put a blanket over the amp. Then it came back. Did this a few times then dropped out completly. Both channels gone.

Turned off and used a different amp for rehearsal then today I plugged in to trouble shoot. Same thing happening, serious volume drop. Changed out the power tubes since they were over a year old and I play a lot, the were looking very orange instead of blue.

But it is still happening? Could it be a pre tube? Maybe V4 since that is the phase spliter/driver tube? Could it be something else and I am wasting my time on the tubes?

HELLLPPPP.

other info ... the amp is about 5 years old, I reahearse once a week and gig a few weekends a month. It gets lots of use and travels around a lot!

Thanks
Jeremy

 

[fishyfishfish]

I would take all the pre amp cans off the tubes and see if any preamp tubes have a white top or are making any noise when tapped with a pencil.
If all the pre amps look good and there is no funny burnt smell coming from the amp the only other thing I can think of is the loop jacks a dirty like my old lonestar so try a jumper cable in the loop and see if that works. Good luck!