ARMY TM 5-6675-238-14
MARINE CORPS TM 08839A-14/1
(4) Connect a DVM across overvoltage protector
Z2.
(5) Slowly adjust power supply until digital volt-
meter indication suddenly drops, designating
trip-point voltage. Overvoltage protector Z2
trip-point voltage should be +7 (±0.14)V, If
necessary, adjust voltage adjustment to obtain
a + 7 (±0.14)V trip-point voltage.
(6) Disconnect digital multimeter and power sup-
(7) Solder SPU wires to overvoltage protector Z2.
g. Overvoltage Protectors Z3 and Z4 Voltage Ad-
justment. Voltage adjustment of overvoltage protectors
Z3 and Z4 are identical. Peform adjustment of overvolt-
age protector Z3 or Z4 as follows:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Check that SPU ON switch-indicator is off
(switch-indicator is not lighted).
Check that SPU wires are not soldered to
overvoltage protector Z3 or Z4.
Connect an adjustable DC power supply to
overvoltage protector Z3 or Z4 with a 150- to
400-ohm, 10-watt resistor in series with the
positive side of the power supply.
Connect a DVM across overvoltage protector,
Slowly adjust power supply until voltmeter
indication suddenly drops, designating trip-
point voltage. Overvoltage protectors Z3 and
Z4 trip-point voltage should be + 17
(±0.34)V. If necessary, adjust voltage adjust-
ment to obtain a + 17 (±0.34)V trip-point
voltage,
Disconnect DVM and power supply.
Solder SPU wires to overvoltage protector.
h. Logic No. 2 Electronic Component Assembly
Adjustment. Perform logic no. 2 electronic component
assembly adjustments as follows:
(1)
(2)
(3)
(4)
(5)
8-96
Connect cable W201 to 115-VAC power, ca-
ble W203 to the tape reader and cables W204
and W209 as shown in figure 8-2.
Set multimeter to measure ac volts and con-
nect positive test lead to A2TP-1 and negative
test lead to COM test jack (figure 8-9). See
figure 8-8 for location of components and
controls.
Press SPU ON switch-indicator to on (switch-
indicator lights).
Check that multimeter indicates 25 to 27
VAC. If not, adjust resistor A2U9R1.
Set DVM to read DC and connect DVM posi-
tive test lead to A2TP-3 and negative test lead
to A2TP-4,
NOTE
Check that tape reader head is clean.
(6)
(7)
Set tape reader SPOOLING switch to DIS-
ABLE:
Install self-test tape on tape reader, Set tape
reader SPOOLING switch to ENABLE,
NOTE
The first section of the self-test tape is the
SPU self-test sequence. It is then followed
by 50 feet of rubout (all holes), then
followed by the calibration section.
(8) Press MEMORY LOAD switch-indicator to
advance tape to calibration section of tape.
When the last 10 inches of rubout appears,
press MEMORY LOAD switch-indicator to
off.
NOTE
In the following steps, the tape can be
rewound at any time by pressing the
SELF TEST switch-indicator to off, then
pressing the REVERSE switch-indicator
to on. Press the REVERSE switch-indica-
tor to off when desired location is
reached.
(9) Press SELF TEST switch-indicator to on. The
tape will advance and the FAILURE/AC-
TION indicator displays 50.
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
Verify that DVM indicates -9.995 to
-10.005V. If not, adjust resistor A2R5.
Press SELF TEST switch-indicator to off.
Press SELF TEST switch-indicator to on. The
tape will advance and the FAILURE/AC-
TION indicator displays 52.
Verify that DVM indicates +9.990 to
+ 10.000V. If not, adjust resistor A2R3.
Press SELF TEST switch-indicator to off,
Press SELF TEST switch-indicator to on. The
tape will advance and FAILURE/ACTION
indicator displays 54.
Verify that DVM indicates 0 (+0.005)V. If out
of tolerance, replace A2.
Press SELF TEST switch-indicator to off.
Press SELF TEST switch-indicator to on.
Tape will advance and FAILURE/ACTION
indicator displays 56.
Verify that DVM indicates -4.995 to
-5.005V. If out of tolerance, replace A2.
Press SELF TEST switch-indicator to off.
