Fender Tremolux Amp

[hotwatt]

Hello, I recently acquired a Fender Tremolux amp. However its not working and only a little hum is heard from the speaker cab. I have tested all the tubes in other amps that I own and they continue to work with the Tremolux's tubes installed. I was thinking about replacing all the capacitors but really dont want to replace original parts if its not necessary. The circuit looks to be made up of only caps and resistors. How can I check if these are working? Thanks.

 

[crutschow]

First thing is to check the power supply voltages to see if they are correct.

To go beyond that you need a schematic to check voltages at other points in the circuit.

 

[Nigel Goodwin]

Don't randomly replace things, fault find to see what's wrong.

A good starting point is to check the voltages on the anodes of the triodes, by FAR the most common fault is high or O/C anode load resistors on the trioses.

 

[Mikebits]

And take care, high voltage will be present.

The schematic for your amp can be found here.
https://www.ampwares.com/fender.asp

 

[BrownOut]

And take care, high voltage will be present.

The schematic for your amp can be found here.
The Amp Guide » Fender

Man, that's awesome support. Wish I had a website like that for my junk.

 

[flat5]

Try to inject a signal and work your way back from the output tube(s).
Meaning, use a screwdriver and touch the grids of the tubes starting at the end of the amp.
Other arm and other body parts NOT touching anything.
Listen for hum. If no hum that stage is not amplifying. If you short the grids to chassis for a moment and you get a BIG click out of the speaker you may have a very leaky coupling cap on that grid to the previous plate circuit of the tube before it.
Grounding the cathode of a tube for a moment might cause it to amplify. That might lead you to suspect a bad cathode resistor.
You can test most resistors without removing them with a cheap volt-ohm tester. (Power off) Of course you can use this tester to test all voltages.

Good luck! If you do some reading on how tubes amplify you can test the voltages at the tube sockets to get useful info.