I have a Fender Champion 100 which sounds great some the time but randomly stops powering on properly and just blinks the power LED. Next day it is likely to work.
Everything I go to look at it it works fine. Tapping the PCBs in various places makes no difference. No obvious bad solder joints.
Any pointers please?

Resolved. A combination of bad tubes and intermittent switch contacts on extension speaker socket

Hi all I have 1996 Fender Deluxe which is popping and crackling.
Noise is there when all controls are set to minimum so I'm assuming that points to power amp stage. Tubes are not microphonic but is it still likely to be them causing the issue?
All switches and controls have been checked and cleaned and solder joints all appear good.
Any input appreciated.
Paul

I have a problem with a multi watt dual rectifier head.
It keeps blowing fuses and a rectifier tube.
Using the light bulb mains lead method, even with both rectifier tubes out of the unit and on standby it seems to be drawing quite a bit of current. No change with power tubes also removed.
Is this likely to be the large filter caps going or any other suggestions?
Thanks in advance

I have a DSL401 combo which sounds great on clean channel but both OD channels give a loud nasty buzz drowning out the guitar signal. This only exists with an input signal and is not there when signal is put in the fx return so must be something in pre amp section any ideas?

Having resolved rectifier issue on this amp and having replaced all tubes the amp now works BUT when I plug a guitar lead in, what is a barely audible tick becomes loud and clear. Turning the cut control down makes it worse. It is there where tremelo circuit is on or off.
The tick pattern is constant changing to a harder tick every few seconds.
Can anyone assist? Is it a filtering cap gone awol?

Yes all 1k5 and 100R grid resistors charred and destroyed.
I've seen 100Rs before but not both.

Hi all,
I have Vox AC30 jimi era Combo come to me with all of its 100R 1W grid resistors and associated 1W 1k5 resistors totally fried.
Obviously these will all need replacing and I will most likely uprate at the same time but would be the likely cause of the damage?

Yes spot on. They are the same.
Do we think a blown valve would be likely to make C184 "explode"?

Does anyone have a schematic for a vox vt120+ valvetronic combo please.
Or even be able to tell me values for C184 and C185 as both are burnt out erasing markings.
Many thanks

I have an early (non reverb) Blackstar HT5 here which has a noisy clean channel which occasionally has volume drop but mainly has a crackle and hiss that appears after about 10 mins of being on.
Both valves have been replaced with new matched ones and all connections have been cleaned, checked and resoldered to eliminate them.
Any thoughts what it could be?
At initial switch on it sounds great.

Ok standby switch was causing an issue.
I'm now getting sound but quiet and distorted on all channels.
I've changed all the tubes and no difference.
Ideas please?

Ok DC voltages with ref to dc gnd are:-
W112
P1 0v
P2 0.1v
P3 0.46v
P4 0.46v
P5 -42v
P6 0v
P7 0v
P8 0v

W113
P1 0v
P2 0.1v
P3 0.39v
P4 0.39v
P5 -42v
P6 0v
P7 0v
P8 0v
Resistantance across tip and sleeve with tubes in is 138k

+15 & -15v supply rails are present

Hi all,
Ok so I got a new transformer from Marshall all fitted ok.
I now get a less bright limiter bulb and no smoking diodes, channel switching works but no sound at all. No sound plugging in to fix return either.
Where do I look next?