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Topic: Classic 30 main power fuse rating |
Michael Haselman
From:
St. Paul
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Posted 17 Apr 2013 4:48 pm |
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I've searched the interwebs and schematics. They give F2 and F3, but I can't find the rating for the one right behind the power switch. I believe it's 3A fast blow but not sure. Keeps blowing, and I'm trying to diagnose a problem before I bring it to the shop.
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Mullen RP D10, Peavey NV112, Hilton volume. Hound Dog reso. Piles of other stuff. |
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Stephen Cowell
From:
Round Rock, Texas, USA
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Posted 17 Apr 2013 10:29 pm
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Can you read the print on the one you pulled out? BTW, pull the final tubes before burning any more fuses up.
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Too much junk to list... always getting more. |
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Ken Fox
From:
Nashville GA USA
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Posted 18 Apr 2013 3:36 am
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You are correct that there is no reference to the AC mains fuse. Form what I have been able to research o t he net it is 3 amp (I would recommend a slo-blo for an all tube amp). That seems in line with the values used in most tube amps of similar wattage. Call Peavey if you still feel uncertain and they will be glad to tell you for sure. They will also be willing to discuss your amp issues with you. Just ask the operator for repair assistance.
F3 is for the two AC filament supplies as well as the DC bias supply. Not an easy amp to trouble shoot as there are two filament supplies, one for the power tubes and one for the preamp tubes. The filaments are wired in series and that means if any a tube is pulled then the filaments for that section of tubes will all go out.
Having spent time working on one of these I would say it's time for you to send it to Peavey for repair, unless you are good at soldering, reading schematics, have proper test equipment, etc. Their repair rate is one of the lowest in the industry and they will get it right for you. |
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Michael Haselman
From:
St. Paul
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Posted 18 Apr 2013 5:33 am
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Thanks much. I'll try a slo blow. What's the "final tubes?"
_________________
Mullen RP D10, Peavey NV112, Hilton volume. Hound Dog reso. Piles of other stuff. |
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Ken Fox
From:
Nashville GA USA
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Posted 18 Apr 2013 5:37 am
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| power amp tubes, EL84 |
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Michael Haselman
From:
St. Paul
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Posted 18 Apr 2013 11:40 am
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One more question for you 2 gurus. I put slo blow 3A mains fuse in. Now, the 1A F2 fuse keeps blowing. I actually had a sound for about a second, then it blew, mains fuse OK, tubes all lit. I know I need to bring it in, but does this tell you anything?
_________________
Mullen RP D10, Peavey NV112, Hilton volume. Hound Dog reso. Piles of other stuff. |
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Stephen Cowell
From:
Round Rock, Texas, USA
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Posted 18 Apr 2013 12:29 pm
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Did you pull the EL84's and try it? The common failure mode is a shorted EL84. Pull all of them out and see if the fuse blows. If it doesn't, replace the EL84's and try again. Don't just replace one, they're all probably worn out... replace them in sets, like tires.
Read this:
http://www.thegearpage.net/board/archive/index.php/t-253711.html
for more information on replacing output tubes in your amp.
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Too much junk to list... always getting more. |
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Michael Haselman
From:
St. Paul
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Posted 18 Apr 2013 1:24 pm
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Well, just had a new set of JJ's put in last trip to the shop, about 3 months ago. I did pull the EL84's, and it did not blow. But, this would be a hell of a lot cheaper than another trip.
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Mullen RP D10, Peavey NV112, Hilton volume. Hound Dog reso. Piles of other stuff. |
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Michael Haselman
From:
St. Paul
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Posted 18 Apr 2013 3:28 pm
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OK, end of my story. It did blow the 1A fuse with the EL84s removed. No more messing with it by me.
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Mullen RP D10, Peavey NV112, Hilton volume. Hound Dog reso. Piles of other stuff. |
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Ken Fox
From:
Nashville GA USA
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Posted 18 Apr 2013 4:45 pm
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Sounds like one or more shorted diodes in that B+ supply or a shorted filter cap. Still it is supplying B+ to the preamp tubes. If all tubes are removed and it blows the 1 amp fuse then the diodes and filter caps need to be checked for sure. Also a short to ground on the primary windings of the output transformer could be at fault as well.
The one I had did have bad diodes, a bad power transformer and a bad output transformer, burned traces and more. It has been ran to death! Rebuilt it and it ran great. Lots of work and not a fun chassis to work on. |
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