JCM 800 Bass Amp Loud cracklilng

[dpm309]

I have a Marshall JCM 800 Bass series, 100 watt that has a very loud crackling when it is powered up, even with nothing plugged into it and the volume turned all the way down. Someone replaced one of the Cliff jacks (looked like cold solder joints) so I resoldered it with no luck. I plugged a dummy plug into it and it reduced the crackling a bit. Removed it and all works fine. The jack looks brand new so I am wondering if it might be defective or the PCB was damaged. I don't have a spare cliff jack that I can replace it with. Any suggestions?

[shooter]

Any suggestions?

any room to temp-in a switchcraft and wire?
any "spare" cliffs that you can "borrow" from, say, send/return, line out, etc.?

[sluckey]

Pull little tubes starting at the preamp and working toward the PI. Which tube pull kills the crackle?

[dpm309]

Well, it turns out that whoever installed the new cliff jack, bunged up the traces on the PCB. Cleaned everything up and re-soldered the jack and now it works like a charm. Second time I have worked on this amp. The first time the owner installed a new power tube socket and had wired it incorrectly. Every pin was off by 1! Hope this teaches him a lesson to not try any more repairs on his own.

Thanks for the input and sorry if I wasted anybody's time on this. I should have known better.

[DummyLoad]

Hope this teaches him a lesson to not try any more repairs on his own.

why not? how else is your friend supposed to gain experience?

respectfully,

--pete