Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on January 08, 2012, 07:56:43 pm

Title: Hot Rod deluxe problem
Post by: LooseChange on January 08, 2012, 07:56:43 pm

I've got a HRD on the bench and I have a strange problem I can't seem to figure out.
There is voltage on the grid of V1A, Pin 2. About 0.8volts with the tube in and around 2.1volts with the tube pulled. Got any ideas?

http://www.el34world.com/charts/Schematics/files/fender/hotrod_deluxe.pdf (http://www.el34world.com/charts/Schematics/files/fender/hotrod_deluxe.pdf)

Thanks!

Title: Re: Hot Rod deluxe problem
Post by: Tiny_Daddy on January 08, 2012, 09:38:15 pm

Leaking over from Pin 1? Lift the 100K resistor and see if it goes away.

Title: Re: Hot Rod deluxe problem
Post by: LooseChange on January 09, 2012, 06:42:35 am

I'll try that.

I've worked on dozens of these amps and this is a first.
Always a fun time with these amps, pc board and all.

Thanks!

Title: Re: Hot Rod deluxe problem
Post by: birt on January 09, 2012, 10:43:24 am

i would check the ground connection of that first gain stage.