SP-210 Tube Socket Voltage/Resistance

SP-200 Series Troubleshooting Data

Data apply to BC-779-B, BC-794-B, and BC-1004-C

Reference: U.S. Army TM11-866

TABLE 1 -- TUBE SOCKET VOLTAGES

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| Socket Tube Voltage wrt GND at tube socket terminal number |
| Number Number 1 2 3 4 5 6 7 8 |
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X1 V1 0 0 250 135 135 6.3ac 0
X2 V2 0 0 250 135 135 " 0
X3 V3 0 0 250 115 " 0
X4 V4 0 0 150* 150* 150* "
X5 V5 0 0 250 135 0 " 0
X6 V6 0 0 0 -43 0 135 " 250
X7 V7 0 0 0 -1.5 0 100 " 240
X8 V8 0 0 -.2 .4 -.2 " .4
X9 V9 0 0 .4 0 0 .4 4.0ac -.2
X10 V10 0 0 0 0 40 6.3ac 155
X11 V11 0 0 0 -1.5 0 110 " 240
X12 V12 0 0 -3.2 -3.2 -3.2 " -3.2
X13 V13 0 0 110 -3.2 " 0
X14 V14 0 0 240 240 -20 " 0
X15 V15 0 0 380 380 0 " 38
X16 V16 0 0 380 380 0 " 38
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Notes: Terminals 1 and 2 of all sockets are at zero potential with respect to chassis
*Varies widely with different tubes; also with dial setting

The above voltage readings are based on an a-c line voltage exactly
equal to the primary tap on the power transformer -- higher or lower
line voltage should result in corresponding variations in these readings.

All d-c readings are based on the use of a meter having a resistance of
1000 ohms per volt, and are taken between socket terminal and chassis.

Settings: SENSITIVITY and AUDIO GAIN should be set to 0
SIGNAL-MOD-CW switch should be on CW
AVC-MANUAL switch should be on MANUAL
SEND-REC switch should be on REC
LIMITER switch should be ON


TABLE 2. SOCKET TERMINAL RESISTANCE VALUES.

(All measurements made between socket terminal and chassis)

RECEIVER
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| Terminal | Pin | Variable | Resistance |
| Name | No. | Ref No. Setting | in ohms |
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V1 grid Cap SW4 AVC 1,160,000
SW4 MAN 515,000
V1 plate 3 SW2 SEND infinity
SW2 REC 20,000
V1 screen 4 11,500

V2 grid Cap SW4 AVC 1,160,000
SW4 MAN 515,000
V2 plate 3 SW2 SEND infinity
SW2 REC 20,000
V2 screen 4 11,500

V3 sig grid Cap 510,000
V3 plate 3 SW2 SEND infinity
SW2 REC 20,000
V3 screen 4 SW2 SEND infinity
SW2 REC 43,000
V3 inj grid 5 50,000

V4 grid Cap 50,000
V4 plate 3,4,5 30,000
V4 cathode 8 0.1 to 1.8*

V5 grid Cap SW4 AVC 670,000
/SW4 /MAN 14,600
\R56 \0
/SW4 /MAN 10,300
\R56 \10
V5 plate 3 20,000
V5 screen 4 11,500

V6 grid Cap SW4 AVC 670,000
/SW4 /MAN 14,600
\R56 \0
/SW4 /MAN 10,300
\R56 \10
V6 screen 6 11,500
V6 plate 8 20,000

V7 grid 4 10,300
V7 screen 6 68,000
V7 plate 8 20,000

V8 plates 3,5 217,000
V8 cathodes 4,8 250,000

V9 plates 3,6 250,000
V9 grids 4,5 1,220,000
V9 heater 7 4**
V9 cathode 8 SW5 ON 117,000
SW5 OFF infinity

V10 grid 4 100,000
V10 screen 6 SW3 CW 523,000
SW3 MOD infinity
V10 plate 8 SW3 CW 73,000
SW3 MOD infinity

V11 grid 4 10,300
V11 screen 6 68,000
V11 plate 8 20,000

V12 plates 3,5 35,300
V12 cathodes 4,8 300

V13 plate 3 68,000
V13 grid 5 500,000

V14 plate 3,4 18,600
V14 grid 5 500,000

V15 plate 3,4 19,400
V15 grid 5 320
V15 cathode 8 750

V16 plate 3,4 19,400
V16 grid 5 320
V16 cathode 8 750
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* Varies with band change switch setting
** with V9 removed from socket

POWER SUPPLY Units RA-74-C, RA-84-B, RA-94-A
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V1 Plate 2 40 ohms (55 ohms for RA-74-C)
V1 Plate 3 " " " " " "
V1 filament 1,4 19,500 ohms

V2 plates 2,3 28,500 ohms
V2 filament 1,4 22 ohms (34 ohms for RA-74-C)
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