The clean channel does not get very loud. You can turn it all the way up and it is not loud. I did wiggle the input cable at the lnput and for a second it got very loud. I figured it needed a new 1/4 inch input so I got a new one and soldered it in. Still does the same thing except this time you can't get it to kick in loud by wiggling. The Dirty channel works fine and is very loud. Anyone have this problem or know what else to check?
Help with a 90s marshall valvestate 40
- Thread starter Spanky
- Start date
Sorry I have no idea.
Amp Mad Scientist
Ambassador of Heresy
Resolder the connections in the clean channel starting with the pots...
you might be able to find the bad solder spot by poking flexing the board with a wooden chopstick. But bunk solder connections may not be visible just to the eye...
and so sometimes I just resolder / reflow them all.
Amp Mad Scientist
Ambassador of Heresy
Yup,
cracked solder is really common in guitar amps especially where the pots and jacks are soldered to the PC board.
Pretty much all Fender HRD and Marshall 900s...I wind up re-soldering a large portion before the amp works right.
More than likely because the boards are wave soldered by a machine and the solder never flowed correctly to start with at the factory.
cracked solder is really common in guitar amps especially where the pots and jacks are soldered to the PC board.
Pretty much all Fender HRD and Marshall 900s...I wind up re-soldering a large portion before the amp works right.
More than likely because the boards are wave soldered by a machine and the solder never flowed correctly to start with at the factory.
Thank you I will take it back apart I didn't think to check all pots and connections. It makes more sense to me now the input jack is used for both channels and the dirty side works fine.
Several years ago, I fixed the effects loop of one of my amps by doing this very thing. Using a strong magnifying glass, I found a crack in the solder joint of one the PCB mounted jacks. Reflowing the solder was all that was necessary to restore it to proper operation. It's worked fine ever since.
Do you have a schematic? I agree with AMS that it sounds like a cold solder joint. On the 8200 and 8280 there is a common input transistor TR1 and then the signal splits into the clean and dirty channel circuitry. I’d look at the components after that first transistor in the clean channel.