Re: VOX AC30/6 TB
- From: "DaveM" <masondg4499@xxxxxxxxxxxxx>
- Date: Wed, 18 Apr 2007 17:51:21 -0400
"N Cook" <diverse8@xxxxxxxxx> wrote in message
news:f05703$l48$1@xxxxxxxxxxxxxxxxxx
All valve, no solid state devices, probably made 2002 from barcode date? and
2001 date on Sovtek 5AR4.
Powered on for about 5 seconds with cracks and bangs then HT light went out
and dead.
Inside looks and smells fine but "gently" blown HT fuse. I've not tested the
valves yet.
1 of the 22K 1/3W HT R/C dropper resistors slightly discoloured and all 4
EL84 1/2W, 100 ohm grid resistors slightly discolured. Someone has crudely
cut one of the 2 grounds to the pcb, presumably trying to reduce hum when it
was working.
All DVM DC resistance measurements of the transformers seem ok.
Any pointers to known problems with this version?
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
First question back to you is.. is the HT fuse after the rectifier or before it?
Or, are you really talking about the AC mains fuse?
If the fuse is really in the AC mains line, then almost all my bets are going to
be on a shorted power transformer or a shorted MOV or line bypass capacitor.
If the fuse is after the rectifier, then you should pull the rectifier tube,
replace the fuse, and see if the fuse blows again. If it blows again, then
check to see if maybe one side of the power line is shorted to ground...
possibly caused by a shorted MOV or line bypass capacitor. Or a stray piece of
wire, or other malady.
If the fuse doesn't blow again, then you have a bit of troubleshooting to do.
Most likely a shorted B+ filter capacitor or shorted tube. Be sure to keep your
eyes peeled for stray wire clippings.
Cheers!!!!
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)
Life is like a roll of toilet paper; the closer to the end, the faster it goes.
.
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