Marshall Combo problem!!

[Bryan]

Just got my "new" Marshall DSL 401 from ebay. Everything works fine until I go to the OD channel. When I do this very loud constant squeal comes from the amp. It only stops if I play again, switch to the clean channel, or unplug the guitar. I tried my other guitar and different cords so I know it's the amp. I figure it's probably a bad tube but I really don't know what to do. I would appreciate any help on this.

Thanks up front!

[Bryan]

Never mind. Problem solved. I contacted the seller and he was nice enough to walk me through the testing process and it seems a microphonic tubes was damaged in shipping. He was even nice enough to compensate me for the broken tube. Isn't that cool?

Yay ebay!

[JACKSONFREAK]

Sounds like a bad preamp tube. Or a bad swtich connection on the gain channel. try the tubes first and see what happens.
Gil

[JACKSONFREAK]

ok well then never mind

[Bryan]

Thanks anyway!!