Marshall DSL short ???

[Valvehead]

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[Valvehead]

1st question-- which wire on the secondary of ot is the common/ground ? Orange or black ? No colors on the scem.

Ok, i jsut tried using a jvm ot with this amp--it worked but sounded very thin--obviously not compatible.

So i just received a new jcm 2000 ot.

Ive got it clipped in, and when clicking on the standby to run--i get a big flash at v4 tube socket and it blows the ht fuse--this is with no tubes . I also have a light bulb current limiter in line !

Ive triple checked the wiring. Ct wire is blue , plates are white and purple.its easy to see where they go on the pcb.

I have those correctly clipped to the new trans--wiring is correct. The secondary is not hooked up. New trans is a classic tone = ct is brown, plates are white / red.

I had the pcb out this week and everything looks good there.

Im stumped because the amp worked with that other trans yesterday !

Any thoughts ??

I guess i will pull the pcb again and inspect-----but again..it worked with the other trans..

edit---the spark is under v3 socket-----the one i replaced.....im pulling the pcb--and i bet i will find the problem....

[Valvehead]

Ok...i see that 2 of the socket pins were shorting together. I dont know how or why......but ive got a new socket here, and im going to make strategic cuts in the pcb with a dremel so it wont happen again (i hope)

[Enzo]

Is it the power tube next to the power transformer? Pins 3 and 4? There is a small disk cap between those two pins on that one socket only. It can short.

Or do you have an actual arc - a burnt spot?

[Valvehead]

It was the 3rd power tube socket ...i removed that cap last week from v8...i know all about that lil bugger.... it was a short somehow from pin 3 and 4. I replaced the socket and dremeled out some pcb in that area---amp is up and running now. Ive been fighting this amp for 5 hours straight tonight......gremlin after gremlin....the rectifier for the 1st 2 pre tubes actually went out during this fight.......and by some magical luck--i had a new one here. BR12. Man....what a long night...the amp is working.........until tomorrow. Im afraid to turn it on !