Marshall Silver Jubilee switching issues

[devuurzil]

I have a marshall head, model 2555, with an issue. when i turn it on the clean sounds fine, and when I switch to dirty, the dirty sounds fine, but when I switch back to clean it either turns into a farty hummy mess or stays exactly the same as the dirty......im freakin out, any help would be much appreciated.

[Gtr_tech]

I have a marshall head, model 2555, with an issue. when i turn it on the clean sounds fine, and when I switch to dirty, the dirty sounds fine, but when I switch back to clean it either turns into a farty hummy mess or stays exactly the same as the dirty......im freakin out, any help would be much appreciated.

Sounds like the relay contacts are oxidised, but that shouldn't make the dirty ch "stick on". Make sure the realy is switching as it should first, then pull it out and clean the contacts. Don't file/sand them. Clean them off with a swab and some de-oxit or similar. As long as the relay is kicking like it should, that should get you back in business.

[booj]

I looked at the schematic of a Slash 2555. It has no relays that I can see. The switches could be giving you some grief. Please post the fix you come up with. Sounds like a headscratcher.

[booj]

Oops. Ok. I see the relay. It switches between what looks like an assymetrical diode combination or no diodes. I can see that relay giving you grief.