Mains Fuse
“
blowing
“
Unplug amplifier from the wall AC.
Remove the power tubes.
Install a new
3
amp slow
blow fuse
( 2 Amp 240V )
.
Plug into the wall AC and turn the amp on. If amp continues to blow the mains fuse, your
amp will need to be serviced. If the fuse does not blow, and the amp lights up, turn amp off,
and install a new set of matched EL 84 power tubes. Turn the amp back on. If the fuse does
not blow, play the amp and monitor. If the high voltage H.T. fuse blows, it is most likely a
defective power tube, or your bias setting / current draw may be too high.
Amp Lights Up, - No Sound
Check / test / replace - the 1/2 amp
H.T.
fuse for continuity with a digital Ohm meter. It may
be blown. Check the speaker connection at back of amp and at the input of cabinet.
Bypass all pedals and effects and plug your guitar into only the amplifier.
Check your guitar cable.
Check the power and the pre amp tubes and make sure that they are installed correctly and
that the filaments within each tube are lit. Sometimes they can look operational - ( with the
filaments lit ) - but be defective in not passing signal.
Amp has Humming, Hissing, Feedback or Crackling sound
Most likely a bad pre amp tube. Pre amp tubes can develop problems over their life span.
They may operate flawlessly over time, and they may also test fine on a tube tester, but for
what seems like for no reason, they can suddenly begin to make a “
hissing
“ sound, or
develop filament “
humming
“ noise or exhibit a
“
crackling
“ sound. They can also begin
to feedback or have microphonic or “
ringing
“ symptoms
. ( See previous section titled: ECC
83, 12AX7, 7025, and CV4004 )
Unfortunately, you may have to replace one of more of your pre amp tubes. This is another
reason we stress purchasing N.O.S. tubes. They are less likely to go bad. Fluorescent and
neon lights, rheostat wall dimmers, and some appliances may cause your amp to contain a
“
hum
“ or “
buzz
“ sound. Also, check your guitar cable if you discover that the problem is
not a pre amp tube.
Over time, the input jack may occasionally make a "
crackle
" sound when you extract your
instrument cable from the front panel of your amp. This would require that the inside of the
input jack be cleaned professionally. We recommend using DeoxIT
®
GOLD G5.
Copyright 2000-2012, Riverfront Music, L.L.C. d.b.a. Komet
Amplification. May not be reproduced in any form without express written
consent from Riverfront Music, L.L.C. d.b.a. Komet
Amplification.
