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TM 55-4920-412-13&P
s.
Monitor Boards NO 1 (A7) and NO 2 (A8).
The following performance tests check Display
Pulses, Shift Register Monitor, Digital O/P, MUX Analog,
MUX Digital, Digital MUX, Analog MUX circuits and
CONVERSION switch.
(1)
Set Power to OFF and connect test
equipment as shown in figure 4-1 and figure 2-2 with unit
tester connected to interconnect cable.
(2)
Connect (VIDS) cable assembly P/N 217-
41941-000, between simulator tester NO. 1 connector
and SDC (P/N 245-476850-000 (listed as 476850-000
on the SDC nameplate) or P/N 100401562-000) J1
connector.
(3)
Connect (VIDS) cable assembly P/N 217-
419747-000, between unit tester J8 connector and SDC
J2 connector.
(4)
Connect (VIDS) cable assembly P/N 217-
419748-000, between unit tester J9 connector and SDC
J3 connector.
(5)
Place simulator test switches and controls
as follows.
(a)
ALL CAL-NOR switches NOR.
(b)
ALL HI-LO switches LO.
(c)
ALL NOR controls fully ccw.
(d)
INTEGRAL LIGHTING switch EXT.
(6)
Place Unit Tester SDC switches and
controls as follows:
(a)
Clock INHIBITOFF.
(b)
Failures PROC OFF.
(c)
Failures TES FREQ OFF.
(d)
P/S CONTROL Midposition.
(e)
P/S CONTREMOTE.
(f)
DISPLAY UPDATE ON.
(g)
INTERCAL SELECT OFF.
(h)
CONVERSION Switch A(1) position.
(7)
Connect Digital multimeter between TEST
POINTS 1 (+) and SDC COM (-) on front panel of unit
tester.
(8)
Set Power to ON. Digital multimeter will
indicate between +4.5 and +5.5 Vdc.
(9)
Set Power to OFF and disconnect TEST
LEAD from TEST POINT (+) and reconnect to TEST
POINT 2 (+). Set Power to ON. Indication will be as
specified for TEST POINT 1. Observe that SHIFT REG
MONITOR lamp is ON. Set CONVERSION switch to L
(2) position. SHIFT REG MONITOR lamp will go off.
(10)
Set POWER switch to OFF position.
Disconnect SDC and replace with SDC PIN 100-481440-
001 or P/N 100-601147-000 or P/N 100-601572-000.
Set POWER switch to ON position, The SHIFT REG
MONITOR lamp will turn on. Set CONVERSION switch
to A(1) position. The SHIFT REG MONITOR lamp shall
remain on. If indications are normal, go to step (17)
below. If not perform (11) thru (16) below.
NOTE
Care
must
be
exercised
when
installing and removing extender
cards. Be certain the plugged socket
on the circuit card does not bend the
pin on the extender card.
(11)
Set Power to OFF. Remove monitor
board NO. 1 (A7) and carefully reinstall using extender
board.
Table 4-37. Troubleshooting Monitor Board 1 (A7) Display and Pulses to Monitor Board (A8) Circuits
Trouble
Probable Cause
Remedy
5 vdc low or missing (input)
Logic Power Supply A3 Input 8V
Replace defective components or
(test loop 3)
missing to Regulator Board (A4) or
boards (A3),(A4). See figs. FO-7,
Output 5V missing from (A4).
FO-8 and FO-15.
OUTPUT A display pulses incorrect
U15,U13,U11,U7,U5,UU1U 9.
Replace Board (A7) or components.
(test loop 114)
U9, U35.
See figs 4-23 and FO-15.
OUTPUT B display pulses incorrect
U16,U14,U12,U8,U6,U4,U2,
Replace Board (A7) or components
(Test loop 116)
U10, U20, U36.
See figs 4-23 and FO-15.
SHIFT REG MONITOR lamp
U 15,U6,U17,U18,U19,U20,
Replace Board (A7) or switch S-19.
does not indicate conversion
Switch S-19.
See figs 4-23, 4-24 and FO-15.
between UH-60A and UH-60L SDCs
Change 2 4-67
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