I'm a dumb newbie!

P-Nutz · 11-03-2009, 09:49 AM

I've been playing since I was 6 (I'm 48) and have always used tube amps. Sunday after a Saturday night gig, I was changing out some preamp tubes in my JCM 8000 TSL602 because they were microphonic.

Turned the amp on, no sound. Cranked it. No sound. Realize I had f@#$%d up BIG TIME: I had forgotten to plug the speakers back in ...

I'm guessing I need a new output tranny (as well as a new freakin' brain!); any suggestions ... for the output tranny, that is?

Peace.

P-Nutz · 11-03-2009, 10:15 AM

And, I obviously don't know where to post things: mods, please move to the repair forum. Sorry about that, chief.

Peace.

thrawn86 · 11-03-2009, 05:25 PM

Gahhh....you might need new parts.....

Have you tried using the old preamp tubes and connect to the speakers to test?

American Viking · 11-03-2009, 06:28 PM

sounds like an output transformer. Of course check the simple things first like see if maybe it's just a fuse. If not a fuse then check the tubes again, if not tubes than the OT.

Wilder Amplification · 11-03-2009, 07:03 PM

If you didn't see or smell any smoke or see any flashes in the valves you may have gotten lucky. Plug a speaker and a guitar in and try it out.

P-Nutz · 11-03-2009, 07:35 PM

Unfortunately it's blowing fuses like crazy, so I did fry something. I'm taking it to a tech tomorrow.

This guy is new to me, not my usual guy because he is backed up really far. This is my gigging amp, so ...

Whaddya all thing of Mercury Magnetics? More hype than mojo? Any suggestions?

Peace.

Wilder Amplification · 11-03-2009, 08:21 PM

Quote:

Originally Posted by P-Nutz

Unfortunately it's blowing fuses like crazy, so I did fry something. I'm taking it to a tech tomorrow.

This guy is new to me, not my usual guy because he is backed up really far. This is my gigging amp, so ...

Whaddya all thing of Mercury Magnetics? More hype than mojo? Any suggestions?

Peace.

Mercury Magnetics are badass transformers. That's not a "biased" opinion either (pun intended)...yes I do happen to be one of their dealers, but I totally dig the tone as well as every customer I've ever installed one for. They've really gone through lots to duplicate (not emulate) the tone of the early transformers and their products are top notch.

They also feature a 30 day tonal satisfaction guarantee as well as a 10 year warranty.

You may have gotten lucky and just shorted an output valve...but we'll see what your tech says. Let me know if there's any way I can be of service.

P-Nutz · 11-03-2009, 09:08 PM

" Let me know if there's any way I can be of service."

Free tranny? Just kidding!

I think I checked after the fuses were frying, and if I recall, all tubes were alight, but I'll go back and check again ... all front panel lights are on, so I'll take THAT as a good sign!

Thanks for all the good answers (esp. for a newbie!)!

Peace.

RiverRatt · 11-03-2009, 09:25 PM

Pull the power tubes and see if it still blows fuses when you take it off standby.

Wilder Amplification · 11-03-2009, 11:36 PM

Quote:

Originally Posted by P-Nutz

" Let me know if there's any way I can be of service."

Free tranny? Just kidding!

I think I checked after the fuses were frying, and if I recall, all tubes were alight, but I'll go back and check again ... all front panel lights are on, so I'll take THAT as a good sign!

Thanks for all the good answers (esp. for a newbie!)!

Peace.

Just because valves light up don't mean that they're good. One of them probably shorted. This isn't a short you can see with a multimeter. It's what they call a "leakage short" and it only appears as a short once you have a certain amount of voltage between the cathode and plate inside the valve.

For this reason, best thing to do would be to take it to a tech. Would like to hear what he finds. I also do repairs as well, but with shipping and all that would be more trouble financially than it's worth. However, if your tech finds that the output transformer is fried, I can't get you a free one (

) but I can get you a deal on a Merc tranny if you decide to go that route.

***Adwex*** · 11-03-2009, 11:45 PM

Quote:

Originally Posted by RiverRatt

Pull the power tubes and see if it still blows fuses when you take it off standby.

That's what I would do, but I would take ALL tubes out. If the fuse doesn't blow, then replace one tube at a time, starting with the preamp tubes....with the amp off before inserting each tube obviously.

P-Nutz · 11-05-2009, 06:49 PM

Adwex and Wilder Amp for the score!

Pulled all of the tubes, put in a fuse, and started to light 'er up. No blow until BINGO on one of the power tubes.

Bought a matched set, replaced, rebiased and badda-bing, badda-BOOM-Marshall heaven.

My tech told me to swing it by, and he looked over the traces, checked a couple of other things, and it's all good.

Thanks for the help, guys!

Peace.

Wilder Amplification · 11-05-2009, 07:07 PM

Quote:

Originally Posted by P-Nutz

Adwex and Wilder Amp for the score!

Pulled all of the tubes, put in a fuse, and started to light 'er up. No blow until BINGO on one of the power tubes.

Bought a matched set, replaced, rebiased and badda-bing, badda-BOOM-Marshall heaven.

My tech told me to swing it by, and he looked over the traces, checked a couple of other things, and it's all good.

Thanks for the help, guys!

Peace.

Good to hear! It is for this reason that the HT fuse exists...to protect the other shit in the amp. Sometimes a screen resistor will fail and/or a valve socket will arc, but in your case you got off scott free.

Don't forget props to Adwex...he was the source of your troubleshooting idea.

When/if you decide you wanna upgrade to a Mercury tranny and choke in that amp, you can have your tech do the work but gimme a call and I can get you a great deal on the Merc parts.

11-03-2009, 09:49 AM	#1 (permalink)
P-Nutz Junior Member Join Date: Aug 2009 Posts: 5	I'm a dumb newbie! I've been playing since I was 6 (I'm 48) and have always used tube amps. Sunday after a Saturday night gig, I was changing out some preamp tubes in my JCM 8000 TSL602 because they were microphonic. Turned the amp on, no sound. Cranked it. No sound. Realize I had f@#$%d up BIG TIME: I had forgotten to plug the speakers back in ... I'm guessing I need a new output tranny (as well as a new freakin' brain!); any suggestions ... for the output tranny, that is? Peace.

11-03-2009, 10:15 AM	#2 (permalink)
P-Nutz Junior Member Join Date: Aug 2009 Posts: 5	Re: I'm a dumb newbie! And, I obviously don't know where to post things: mods, please move to the repair forum. Sorry about that, chief. Peace.

11-03-2009, 05:25 PM	#3 (permalink)
thrawn86 Senior Member Join Date: Aug 2009 Location: Far Nor Cal USA Posts: 423	Re: I'm a dumb newbie! Gahhh....you might need new parts..... Have you tried using the old preamp tubes and connect to the speakers to test? __________________ Drivin' faster in my car... 02 DSL 401-Ei's 02 1960b 02 Gibson LP Studio Silver 03 PRS Santana SE Holy Grail reverb Originally Posted by J. Robert Oppenheimer "We knew the world would not be the same."

11-03-2009, 06:28 PM	#4 (permalink)
American Viking Senior Member Join Date: Jan 2009 Location: RICHMOND, VIRGINIA Posts: 1,510	Re: I'm a dumb newbie! sounds like an output transformer. Of course check the simple things first like see if maybe it's just a fuse. If not a fuse then check the tubes again, if not tubes than the OT. __________________ -I'd rather be a good liver than have one...

11-03-2009, 07:35 PM	#6 (permalink)
P-Nutz Junior Member Join Date: Aug 2009 Posts: 5	Re: I'm a dumb newbie! Unfortunately it's blowing fuses like crazy, so I did fry something. I'm taking it to a tech tomorrow. This guy is new to me, not my usual guy because he is backed up really far. This is my gigging amp, so ... Whaddya all thing of Mercury Magnetics? More hype than mojo? Any suggestions? Peace.

11-03-2009, 09:08 PM	#8 (permalink)
P-Nutz Junior Member Join Date: Aug 2009 Posts: 5	Re: I'm a dumb newbie! " Let me know if there's any way I can be of service." Free tranny? Just kidding! I think I checked after the fuses were frying, and if I recall, all tubes were alight, but I'll go back and check again ... all front panel lights are on, so I'll take THAT as a good sign! Thanks for all the good answers (esp. for a newbie!)! Peace.

11-03-2009, 09:25 PM	#9 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 517	Re: I'm a dumb newbie! Pull the power tubes and see if it still blows fuses when you take it off standby.

11-05-2009, 06:49 PM	#12 (permalink)
P-Nutz Junior Member Join Date: Aug 2009 Posts: 5	Re: I'm a dumb newbie! Adwex and Wilder Amp for the score! Pulled all of the tubes, put in a fuse, and started to light 'er up. No blow until BINGO on one of the power tubes. Bought a matched set, replaced, rebiased and badda-bing, badda-BOOM-Marshall heaven. My tech told me to swing it by, and he looked over the traces, checked a couple of other things, and it's all good. Thanks for the help, guys! Peace.

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