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Post by funkyjazz82 on Oct 5, 2007 7:27:32 GMT -7
Ok, so I replaced the rectifer tube and fuses because it blew a couple months ago, now it works when it wants to. I'll be playing and after 20 min the sound weakens and it eventually just shuts off, no power what so ever, or no sound rather, there is power because the red light is still luminated, but it will shut down, just like that. Then i'll wait 5 or 10 min and turn it back on and it plays perfectly. What could be the case here? And sometimes when i hit the stand by switch and then turn it back on, it won't play. Like I said, I've already replaced the rectifier tube and the fuses. What to do next? Thanks...
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Post by telejas on Oct 5, 2007 9:20:44 GMT -7
Swap around some preamp tubes (but remember where they started from), or get a new one or two and swap out one at a time and see if that fixes it? Maybe even pulling them all out and re-seating them might fix the problem. You might do that with the power tubes too, pull them all out and re-seat them.
Last thing you could do if you can't get the problem fixed would be to do a complete re-tube. I'd call Bob at Eurotubes and he can probably fix you up with a package price on a complete set. If that didn't take care of the problem, it'd be time to go to the Dr (Dr. Z or a qualified amp tech).
I know Mesa Boogies and Dr. Z's are far apart from each other, but I had the exact same problem in a Mesa Tremoverb. The sound just faded out on channel 1 after about 30 minutes of playing, channel 2 worked fine, but nothing from channel one. I took it to my amp tech and he found the problem was a LDR (some diode or resister) was getting hot after 30 minutes and swelling up and shorting out, when the amp cooled down it would shrink and work until it got hot again . Like I said, Boogies and Z's are quite a bit different, but it could be something similar if it's not a tube issue.
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Post by Stylemaster on Oct 5, 2007 9:41:46 GMT -7
+1 on taking it to an amp tech. A good piece of equipment like that - you don't want to mess around with it or second guess what's wrong with it. I learned by my mistakes. Several of them. Unless it just needs retubing, let an expert troubleshoot everything in the amp.
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Post by (8^D) on Oct 5, 2007 10:00:35 GMT -7
$.02...
It is possible you picked up a dud Rectifier - have had some interesting experiences with some of the ROTM generic current production tubes (Sovtek, Boogie-basically Sovtek, etc). If you have another Rec available, give it a try. Might hollar at Myles for a lead on a good NOS or Groove Tube rec.
And, I'd 2nd telejas - swap around the pre tubes.
It's usually something simple. If either of those don't get 'er done, I'd stop right there and take it to a certified/reputable tech...could be anything - bad solder joint, failing cap/diode, cracked tube socket, et al.
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Post by funkyjazz82 on Oct 5, 2007 11:15:37 GMT -7
thanks guys...will try what you guys suggested
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Post by guitarboy02451 on Oct 6, 2007 3:20:25 GMT -7
If all else fails above, call the Doc. It's probably something he can find and fix in under 10 minutes...
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Post by funkyjazz82 on Oct 8, 2007 15:35:26 GMT -7
ok so i rearranged the tubes, now the amp wont even turn on, no red light, nothing. i placed the tubes back in their normal spot, still wont turn on, guess i have to call the doc now. damn it
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Post by Telemanic on Oct 8, 2007 17:08:26 GMT -7
OK, well if it wont even turn on, no red light, youve got a blown fuse again, or something has fried on the A/C side. Typically, this would indicate a problem with your rectifier, or power tubes, or your first filter cap. If the filter cap is going bad when it gets too hot it will short, and it's possible that it could take out power tubes or even your trannies! Normaly a pre tube would not cause the problems your having. I'd really suspect the recto, or the filter cap. If its a russian/chinese DEFINATELY spend the dough on a good NOS, it'll last forever, ...... usually! If your feeling lucky check your fuse and all the tubes are in properly, ( i have a mullard gz34 that the keyway is worn off and if not careful i can get it in there wrong ), power the amp and quickly look at the tubes and see if the recto is lighting up, and if there is any arcing going on in it or the power tubes. Arcing can be intermitant but can take the amp down when it happens. Any tube thats arcing is bad, and needs replacement. BUT your first choice should be get it to a tech or check with Doc first, cause ya could cause more damage!!! Good luck and let us know!
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Post by Telemanic on Oct 8, 2007 17:16:39 GMT -7
Ahh, just saw ya already replaced the recto, so that should be eliminated, unless something else keeps taking it down. Again the first filter cap could be the culprit, they take a lot of voltage and once in a while go bad, but i'm just guessin here without looking at the amp. One good tip is to always have a "known" good set of tubes on hand for diagnosing problems.
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Post by fishman on Oct 8, 2007 17:44:12 GMT -7
Just my opinion but I would take it and send it back to the Z guys for a checkup and a "D&C"---"dustin'and cleanin".....can;t hurt and you can rest assured the problem will be solved and done right...
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Post by dei305 on Oct 8, 2007 19:07:51 GMT -7
funkyjazz82, I agree 100% with Fishman. Send your SR back to the good doctor. He always take great care of his children (and their parents too). My Jr and Sr have been to Doc Z for servicing and they came back sounding even better! Rick
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Post by funkyjazz82 on Oct 9, 2007 7:24:06 GMT -7
appreciate it fellas...
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Post by stratosphere on Oct 10, 2007 19:01:20 GMT -7
You may try putting in another rectifier tube, especially if its chinese. They are reported to have a 50% failure rate.
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Post by guitarboy02451 on Oct 12, 2007 6:20:10 GMT -7
The doc will make it better.
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Post by funkyjazz82 on Oct 24, 2007 8:19:16 GMT -7
ok so check this out- all along the whole problem was having the wrong kind of fuse in my amp. Glad I didn't send it back to the doc for that stupid mistake- that would have been embarressing, but the beauty of it all now is that I can play my halloween gig with the greatest amp ever made!
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