TM 11-5820-801-30
CAUTION
The card is aligned to drive CRYOGENIC TEMP
The terminal layout for S1is as follows-
meter MI Do not change the settings of A1R6 or
A1R12 (fig. 2-9).
2
5
e. Meters M1, M4. M5. Meters M1, M4, and M5 can
3
6
be checked for open circuits or short circuit if diagnostic
procedures (para 3-6) indicate a faulty meter. With all
power off (para 3-2a) remove leads to one terminal of the
When all power is removed from Unit 1 (para 3-2a)
suspect meter. With ohmmeter (multimeter) set on
(cable to J1 disconnected) the following resistance
X1000 scale, check resistance across meter terminals. If
checks can be made on CB1, CB2, and SI.
the ohmmeter indicates infinite resistance the meter
(1) CB1, CB2 Resistance Measurements
circuit is open; if it indicates zero resistance, the meter
Measure across
1-2
3-4
5-6
circuit is shorted; if it indicates a small resistance (order
terminals
(ohms)
(ohms)
(ohms)
of 100 ohms) the meter circuit is likely in satisfactory
CB1, CB2 set to ON
O
O
O
operating condition.
CB1, CB2 set to OFF
Infinite
infinite
infinite
(2) S1Resistance Measurements:
Measure across
2-3
5-6
CB1 (MAIN POWER circuit breaker), CB2 (PARAMP
terminals
(ohms)
(ohms)
POWER circuit breaker) and S1(REFRIG POWER
S1 set to ON
0
0
switch). Terminal layouts are sketched here so that the
S1 set to OFF
infinite
infinite
appropriate terminal (fig. 31) can be easily located. The
(3) CB1 CB2 S2 Voltage Measurements.
terminal layout for CB1and CB2 is as follows:
WARNING
Voltages dangerous to life exist in Unit I
1
3
5
With power cable connected to J1 the following ac
2
4
6
voltages can be measured with a multimeter:
From
To
FL4-1
CBI-2
CBI-4
CBI-6
120 + 12
120 + 12
120 + 12
FtL4-1
CBI-l
CBI-3
CBI-5
CB1 set to OFF
0
O
O
CB1 set to ON
120 + 12
120 + 12
120 + 12
FL4-1
CB2-2
CB2-4
CB2-6
CBI set to ON
120 + 12
120 + 12
120 + 12
FL4-1
CB2-1
CB2-3
CB2-5
CB2 set to OFF
O
O
0
1
FL4-1
CB2-1
CB2-32
CB2-5
CB1/CB2 set to ON
120 + 12
120 + 12
120 + 12
1
CB2-5 to FL4-1 also measures voltage across DS2-1 to DS2-2
2
CB2-3 to FL4-1 also measures voltage across M3.
J6 to El-10
-
2ND STG ON
600 + 600
With CB1set to ON and S1 set to OFF measure from
S1-2 to S1-5: 208 + 21 V
CAUTION
S1-3 to S1-6: O
Do not change the settings of R5 (BIAS 1ST
With CB1set to ON and S1set to ON measure from
STG) and R6 (BIAS 2ND STG). If R5 or R6 is
S1-3 to 51-6: 208 + 21 V
reset, then a gain-bandwidth realignment must
S13 to FL4-1: 120 + 12 V (this is equivalent to
be performed.
measuring DS1Ito DS1-2)
h. Line Filter Voltage Measurements.
g. Switches S4 and S5. Switch S4 (fig. 3-2) and
WARNING
switch S5 can be checked when all cables to Unit 1(at
Voltages dangerous to life exist in Unit 1. The
J1, J2, J3) are disconnected and P1 is disconnected
voltage across line filters FL1 FL2, FL3 and FL4
from PSIJI. Make the following resistance checks:
can be measured between terminals I and 2 of
Measure
S4
S5
Resistance
each filter (fig. 3-2, 3-3). When CBI is set to OFF
from
Set to
Set to
(ohms)
the voltage is zero. When CBI is set to ON the
J5 to E1-8
BYPASS
-
J5 to E1-8
IST STG ON
-
600 + 600
(ac) voltage drop will be less than 5 V per filter.
J6 to EI-10
-
BYPASS
O
3-6
