User Guide

Table 1. C20 VOLTAGE AND RESISTANCE CHART
(Schematic No. SC117-201)
Tube
12AX7
(V1)
12AX7
(V2)
12AU7
(V3)
12AU7
(V4)
12AX7
(V5)
12AX7
(V6)
12AX7
(V7)
6X4
(V8)
Pin No.
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
DC Volts
No. Signal
146
0
1.0
5.6
-5.6
110
0
1.0
—
146
0
1.0
5.6
-5.6
110
0
1,0
64
0
2.4
5.6
-5.6
198
62
120
—
64
0
2.4
5,6
-5.6
198
62
120
—
104
0
.7
5.6
-5.6
230
22
29
_
104
0
.7
5.6
-5.6
200
22
29
-
250
20
70
5.6
-5.6
250
20
70
0
315 AC
—
6.3 AC
0
__
315 AC
335
Resistance in
Ohms Unit Off
130K*
1M
2.2K
5
5
360K*
56K
4K
—
130K*
1M
2.2K
5
5
360K*
56K
4K
_
120K*
<50
1.8K
5
5
14K*
1.1M
100K
—
120K*
<50
1.8K
5
5
14K*
MM
100K
—
330K*
110K
1.8K
5
5
9K
222K
22K
—
330K*
110K
1.8K
5
5
31K*
222K
22K
—
7K*
1M
47K
5
5
7K*
1M
47K
0
580
_
.1
0
—
560
*
NOTES: 1. High impedance VTVM is used to measure operating voltages.
2. Resistance measured to grid, (chassis)
3. * Denotes pin 7 of V8 grounded for this test.
4. Control positions for tests are as follows;
MODE SELECTOR
BALANCE
PHASE
H.F. FILTER
LOUDNESS
INPUT SELECTOR
BASS COMPENSATOR
TREBLE COMPENSATOR
BASS
TREBLE
RUMBLE FILTER,
TAPE JACK,
TAPE COMPARE
VOLUME
LOW FREQUENCY TRIM
STEREO
0
0
FLAT
FLAT
TAPE HD 2
0
TAPE
0
0
OUT
ON, CCW
0