Use this troubleshooting supplement to help:
Measure DC voltage test points to identify major discrepancies and locate problem areas.
(Keep in mind that the voltage measurements will vary slightly from kit to kit. The voltages you measure should be in
the same ballpark, but do not expect to get the exact same value.)
Using a volt meter, connect the ground side lead of the meter to any ground point on the pedal.
One ground point would be the output jack’s ground lug. The other volt meter lead will be used to
measure DC voltage at the test points listed above and shown in the drawing on the next page.
Plug a guitar cable into the input jack and take measurements at each test point with the gain
control turned all the way up. Any major differences from the voltages listed above should indicate
a problem area.
A
B
C
D
E
F
G
H
I
Test Point
Transistor Base Terminal
Transistor Collector Terminal
Transistor Emitter Terminal
Gain Pot “Hot” Lug
Tube pin 2 (grid)
Tube pin 1 (plate)
Tube pins 3 & 4
(cathode & filament)
Tube pin 7 (grid)
Tube pin 6 (plate)
Location Description
DC Voltage Measurement
1.6 VDC
6.9 VDC
0.6 VDC
0.5 VDC
-0.5 VDC
4.8 VDC
0 VDC
-0.4 VDC
7.0 VDC
Tube pin 8 (cathode)
J
K
L
Power Supply
LED Anode (+)
0 VDC
9.1 VDC
2.4 VDC
