Marshall Valvestate 8080 combo, 'Normal' channel not working

[Lunchbox21]

The OD1 and OD2 channel works fine. Enough volume and gain.


The 'Normal' channel, works at gain knob level 2 or 3 (only gain control for normal channel) with some volume .. however, if you slightly go above or below these positions, the amp will go silent. At max gain positions, it will start producing these 'fart' sounds. No idea what might be the reason.

Someone mentioned about TL072. Can that be the solution ?

Please see the video below:
https://www.youtube.com/watch?v=2FqQSMybNPk


The pot readings are fine and gives the values 0-220 k ohm when dialing.

One of the big resistor (see image below) that says 100 ohm J reads 30ohms from the multimeter.



Thanks in advance !!!




Cheers!

[Jon Snell]

Clean the pot.

"One of the big resistor (see image below) that says 100 ohm J reads 30ohms from the multimeter".

That is because it is sat across the transformer and heaters.