FDP Forum / BJr Preamp Tubes Not Working Intermittently/ 5 messages in thread.

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trickeydave



San Diego, CA

"The night has a thousand eyes."
Nov 15th, 2017 11:28 AM        

My ‘03 BJr’s three preamp tubes occasionally won’t power up or have several times shut down while playing. But they will come back on awhile later. Last night at band rehearsal after I powered on my amp, the three tubes wouldn’t light up and of course I got no sound from the amp. I shut it off and checked out the board for loose wires, etc. Saw nothing amiss. I then reattached the back panel and powered on the amp. The tubes came on and the amp sounded fine, normal.<br /> <br /> Any thoughts?



Hammond101

Contributing Member
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So. Cal. USA

Nov 15th, 2017 01:18 PM        

I'd start with these two things. Check all the solder pins for the 6.3 volt heater wiring. I'm not sure it it's in the ribbon cable or is separate green wires, don't remember, but this may be the issue.<br /> <br /> Secondly check the solder pads on the tube socket connections to the daughter board. <br /> <br /> In both cases a cracked solder joint can be difficult to see. I use magnification and most times just reflow these solder joints when servicing a Hotrod series amp.



trickeydave



San Diego, CA

"The night has a thousand eyes."
Nov 17th, 2017 11:21 AM        

Thanks for the suggestions H101! I’ll check them out.



Hammond101

Contributing Member
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So. Cal. USA

Nov 17th, 2017 11:49 AM        

Best of luck!



JJuran

Contributing Member
******

Boston Area

Nov 17th, 2017 03:41 PM        

As always, great input from Hammond101. Just be sure the amp is unplugged and that any/all electrolytic caps are discharged before you put a soldering iron to pins 1 or 6 on a pre-amp tube.



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