Duncan Convertible 2000 - Troubleshooting Common Issues; Amplifier Power-On Problems; No Sound Output (No Hum); No Sound Output (General)

Trouble Shooting
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 250 VAC 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. Modules not installed. 1. Install modules.
(See page 3.)
2. Quick Access module cover
is not installed on top of amp.
2. Install Quick Access module
and allow amp to warm up for
one minute.
3. Amplifier in standby (up)
position.
3. Place standby switch in
"On".
4. Master Volume and/or
Overdrive control levels set
too low.
4. Increase control level
settings to "2" and listen.
5. Speaker output plug
disconnected " output wires
shorted.
5. Connect output plug to 4
ohm, 8 ohm or Variable
Damping input.
6. Instrument pickup/
electronics may be defective.
6. Unplug cable from
instrument and touch tip of
plug; if hum is heard, replace
instrument with one known to
operate properly.
7. Defective speakers 7. Verify speakers operate
properly using another amp.
8. Volume controls on your
instrument are down.
8. Increase settings and listen.
No sound coming from
speakers.
9. Defective center driver tube
12AX7.
9. Replace 12AX7
10. Defective 5U4GB rectifier
power tube.
10. Replace tube.
Loud amplifier hum. 1. Amplifier A.C. polarity. 1. Reverse position of power
"on" switch.
2. Instrument connecting cable
not properly grounded
2. See that connecting cable is
plugged into instrument.
3. EL-34 power tube shorted. 3. Replace EL-34.