Members bob the dentist Posted December 27, 2009 Members Share Posted December 27, 2009 In my 5150 II, two of the 12AX7 preamp tubes are blown/dead/whatever - all i know is that unlike the other four, they are cold when i turn them on. And so are all the 6L6's, but if the preamp tubes aren't working, shouldn't the 6L6's not have any power in them anyway? If i'm right in assuming this, how do I check if the power tubes are dead? it wouldn't be a big deal to have to replace them too, but it would be nice to not have to spend the money on another four. Link to comment Share on other sites More sharing options...
Members hecticone Posted December 27, 2009 Members Share Posted December 27, 2009 I believe you have a larger issue than dead tubes. Find a couple of 12ax7 and throw them in those spots. But I think those will not work either. Tech time. Link to comment Share on other sites More sharing options...
Members bob the dentist Posted December 27, 2009 Author Members Share Posted December 27, 2009 well i dont like ... have tubes laying around what do you think it is though? Link to comment Share on other sites More sharing options...
Members TornadoOfSouls Posted December 27, 2009 Members Share Posted December 27, 2009 Do the lights go on in front of the amp? Or it doesn't turn on at all? Check all the fuses. Link to comment Share on other sites More sharing options...
Members Keebz Posted December 27, 2009 Members Share Posted December 27, 2009 In my experience, when the Power Tubes started failing, it killed the Fuse and wouldn't power up at all. I don't think the Preamp tubes are the issue here. Link to comment Share on other sites More sharing options...
Members bob the dentist Posted December 27, 2009 Author Members Share Posted December 27, 2009 Well, i guess since everyone has decided to only say vaguely ominous things to indicate that they think it's not simply dead tubes, i'll elaborate The amp powers on, the standby works, all the lights on the front work, so it's not a fuse. However, I just swapped the pre amp tubes around, and its the slots that are broken, not the tubes. the 1st and 3rd preamp tube slots are cold no matter what tube i put in it. And no sound comes out of the amp when plugged into a guitar/cab. Link to comment Share on other sites More sharing options...
Members jn062181 Posted December 27, 2009 Members Share Posted December 27, 2009 Well, i guess since everyone has decided to only say vaguely ominous things to indicate that they think it's not simply dead tubes, i'll elaborate The amp powers on, the standby works, all the lights on the front work, so it's not a fuse. However, I just swapped the pre amp tubes around, and its the slots that are broken, not the tubes. the 1st and 3rd preamp tube slots are cold no matter what tube i put in it.And no sound comes out of the amp when plugged into a guitar/cab. Definitely tech time! Link to comment Share on other sites More sharing options...
Members bob the dentist Posted December 27, 2009 Author Members Share Posted December 27, 2009 yeah all the local places around here are closed on sundays, so it looks like this will have to wait til tomorrow at least. humbug Link to comment Share on other sites More sharing options...
Members Jack Tone Posted December 27, 2009 Members Share Posted December 27, 2009 There was a thread here a LONG time ago about 5150 problems. It had a link to a web site that showed there's like 5 or 6 internal fuses in the amp. I'd look there first. Link to comment Share on other sites More sharing options...
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