#1
ok i took my marshall jcm 2000 tsl 2x12 combo to my friends house to jam, and when i turned it on, no noise except for the normal "unplugged" sound. i fiddled with it and i got a little sound when i turned it all the way up, but it sounded very weak with very little/no drive.

none of the tubes immediately look like theres anything wrong, but im not sure. i have a feeling its a preamp tube thats bad. what should i be looking for to see if it is that? or if its not that, what is it?
NOPE
#2
Does it still work fine at your house? It could be the power outlet. If its a preamp tube, it wont light up, they usually glow a little less than powertubes.
#4
yeah lemme add, im at my house now, and it still doesnt work. ive waited with it on standby for 10 min and same thing, no sound unless cranked to 10, then really really weak and thin
NOPE
#5
Quote by Nakon14
yeah lemme add, im at my house now, and it still doesnt work. ive waited with it on standby for 10 min and same thing, no sound unless cranked to 10, then really really weak and thin


Once again, moving it might have killed a tube.
#6
alright, that deffinately could be a possibility. would you think that it would be a power or preamp tube that might be dead?
NOPE
#7
My guess would be power tube since there is sound, but only when turned up all the way. It sounds like the poweramp isn't doing its job of boosting the preamp signal.
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#8
ok update. i had a set of el34s lying around just in case so i tried putting those in and rebiasing and still nothing. i did see though one of the times when i turned the amp on, a preamp tube did flare up for a second, but this was only once. im gonna try to get some preamp tubes tomorrow and see if that works

another question, when i biased the new tubes, they still felt like they were hotter than the other set and i noticed blue spots on the sides of the tubes where there were openings in the plates on the inside. is this normal? i havent seen this before
NOPE
#9
ok heres another update from last night

i got a new preamp tube today since i saw that one flare up a couple times when i turned the amp on. put it in, still same problem. ive switched around where ive had the power tubes to no avail. im starting to worry that im gonna have to take this in for a major repair or something

hopefully someone out here might have an idea whats going on?
NOPE
#10
Try replacing your speaker cable???

Anything in your effects loop? Sometimes if you have your effects send and return reversed, it'll exhibit the signs you're describing
Last edited by zachman5150 at Jan 18, 2009,
#11
You aren't supposed to touch the tubes with bare hands.
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#12
alright i got it fixed that one preamp tube in the metal sleeve went bad and i hadnt checked taht one so it works now thanks to all that helped
NOPE