Arfa Daily wrote in message
...
"N Cook" wrote in message
...
I can understand lager chillers or lighting triacs causing clicks and
bangs
and noises off but blowing fuses on 2 Marshall valve amps at the same
time
and no other pub mains problem showing itself.
The 1987X from 2006 in front of me kept blowing 500mA HT fuses after the
initial failure. Not doing so now its in front of me, not fully checked
out
yet. Mains fuse always ok , just the HT one repeatedly failing after 4
seconds or so. At the same time as this HT one failed the mains fuse
failed
on another Marshall connected to the same supply - that one just
required
a
change of mains fuse and is still ok.
Could a fault causing failure of HT fuse on one amp cause the failure of
mains fuse on another amp , with no pub wiring problem at all, even
problem
local to the power ring/spur to the stage.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Absolutely certain that the supply is not losing the neutral outside
anywhere - particularly if an overhead supply to a country pub ? A friend
of
mine had a similar problem at a remote monitoring station for water
treatment that he had to look after, and the mains kept randomly shooting
up
to 440v. That would certainly cause the secondary voltage of the mains
tranny in the amp, to go up hugely, which would likely blow the HT fuse
and
/ or the mains fuse. Might account for why a similar problem is happening
to
two unrelated items of equipment, simultaneously ? Have they had any
problems with light bulbs failing, particularly any of those new-fangled
eco
things ? Otherwise, I can't think of anything that takes out the HT fuse
on
one amp, doing the same to the mains fuse on another.
Arfa
City pub in Pompey
Owner didn't notice anything else wrong in the room at the gig and
confronting the landlord he said he'd had no problems.
I asked the owner if he used a nasty plastic extension lead and he did not
really reply but even a problem there could not put a surge on to the kit.
Checked the valves and transformers , caps etc and everything seems hunky
dory , no wavering of HT of about 440V on dummy load. I looks as though it
will have to be replacement 500V, twin 50uF electrolytics although no
suspicious heating or bulges /weeping, unless an indisputable reason can be
found. Fuses blew to black interior, ie not soft blown.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/