TROUBLESHOOTING
The following table should enable you, with little or no knowledge of electronics, to
isolate the cause of some problems you may experience with your amplifier and the
steps required for repair. Most causes of impaired amplifier performance are due to
minor problems or irregularities, which can be easily corrected by you. However, if you
cannot identify the cause of the problem using the table below, or if it indicates your
amplifier to be defective and in need of repair, return the unit to an authorized Seymour
Duncan Service Center or call (805) 964-9610 for a Return Authorization number.
Symptom
Probable Cause
Remedy
Amplifier does not come on
when power switch is "ON".
1) Power not connected
1)
Ensure power cord is
plugged into power outlet
2) Blown amp fuse
2) Check amp fuse; replace
if blown with 250VAC
5Amp
SLO-BLOW
3) No source voltage
3) Verify power source with
something you know works
4) Defective ON/OFF power
switch
4) Return unit to dealer or
factory for repair
No sound coming from
speaker(s), (No audible
amplifier hum).
1) Amplifier in standby
1) Place standby switch in
ON (up) position
2) Master Volume and/or
Overdrive control levels set
too low.
2) Increase control level
setting(s) to "2" and listen
3) Speaker output plug
disconnected or output
wires shorted.
3) Connect output plug to 4
ohm, 8 ohm, or Variable
Damping input
4) Instrument
pickup/electronics may be
defective.
4) Unplug cable from
instrument and touch tip of
plug; if hum is heard,
replace instrument with one
known to operate properly
5) Defective speaker(s)
5) Verify speakers operate
properly using another amp
61) Volume controls on
your instrument are down
6) Increase settings and
listen
7) Defective center driver
tube 12AX7
7) Replace 12AX7
8) Defective 5U4GB
rectifier power tube
8) Replace tube
Loud amplifier hum
1) Amplifier A.C. polarity
1) Reverse position of
power ON switch
2) Instrument connecting
2) See that connecting
