Mod TEA PHILTER Owner's manual

1
2
3
INPUT JACK OUTPUT JACK
18
13
472J
1M 1M
1M
1
2
3
5
6
681K
10K
22µF 50V
MPS
A13
104J
104J
10K
1M 1M
RED
BLACK
Use this troubleshooting supplement to help:
Measure 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 voltages at the test points shown below.
DC Voltage Test Points
First, plug a guitar cable into the input jack if you are using a battery for power. Next, take the DC voltage
measurements (Letters in red) at each test point (the potentiometer setting should not alter the DC voltage
measurements). Any major differences between the voltages listed above should indicate a problem area.
C = 6.73 VDC
B = 3.24 VDC
E = 2.33 VDC
PWR = 9.11 VDC
PWR
C
BE
1
2
3
4
5
AC Voltage Test Points
Letter test points are for DC
Numbered test points are for AC
Once your DC voltages look good, you can move on to taking AC voltage measurements
along the signal path. (AC voltages measured while strumming an open E chord on a
strat with single coil neck pickup (volume and tone turned all the up)..)
1 = 0.15 VAC
2 = 0.15 VAC
3 = 0 mVAC @ minimum (7:00) sweep
3 = 15 mVAC @ half-way (12:00) sweep
3 = 60 mVAC @ maximum (5:00) sweep
4 = 0.16 VAC
5 = 0.16 VAC

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“The Tea Philter” (K-970)
Schematic
22µ
50KA
.1µ Output
Input
Foot
Switch
(A)
Foot
Switch
(B)
2
3
165
4
+
+
-
9 VDC
Battery
DC Power
Jack
center (-)
10K
1M
MPSA13
NPN Darlington Transistor
B C
E
MSPA13
C
E
B
1M
10K
.0047µ
.1µ
1M
1M
DPDT Foot Switch
2
3
1
6
5
4
680p
1M
SWEEP
9.11 VDC 0.23 mADC
6.73
VDC
3.24
VDC
2.33
VDC
1
2
3
4
PWR
C
B
E
0.15
VAC
0.15
VAC
0.16
VAC
5
0.16
VAC
60 mVAC @ Max (Clockwise)
16 mVAC @ Mid (12:00)
0 mVAC @ Min (Counter-clockwise)
 DC Voltages measured with respect to ground.
 AC Voltages measured with 50KA sweep pot set to half-way
(12:00), except for test point 3.
AC voltages measured while strumming an open E chord on a strat with single coil neck pickup
(volume and tone turned all the up).
Letter test points are for DC
Numbered test points are for AC