TM 5-3610-253-14
k. Turn on power.
(1) Turn main power switch to I position.
(2) Turn Star-Delta switch to Y position. After the main motor has
reached full speed, turn switch to
position.
(3) Press control power on switch.
l.
Move backgauge forward or backward as required until the backgauge
position is displayed on the measurement display.
m.
With safety bolt in, check pin 20a for +24 V, and pin 20c for 0
volts. Use ground post on SCU as ground.
n.
Manually position the safety bolt in energized (out) position.
o.
With safety bolt out, check pin 20c for +24 V, and pin 20a for 0
volts. Use ground post on SCU as ground.
If steps f, h, m, and o are correct, no problem exists with safety bolt
p.
proximity switches.
If none of these indications are correct, check PS 24 output (paragraph
q.
5-40.63). If output is correct, troubleshoot cabling between safety
bolt switches and SCU unit.
r.
If +24 V was not received on pin 6 a/c of HK board (step f.), and not
received on pin 20a of IAR board (step n.), check cable. If cable is
good, replace proximity switches (paragraph 5-40.47).
s.
If +24 V was not received on pin 7 a/c of HK board (step h.), and not
received on pin 20c of IAR board (step p.), check cable. If cable is
good, replace proximity switches (paragraph 5-40.47).
t.
If problem is still not isolated, failure may exist in SCU motherboard.
Replace motherboard (paragraph 5-40.34).
Turn off power.
u.
(1) Turn Star-Delta switch to Y position, then to O position.
(2) Turn main power switch to O position.
v.
Reinstall circuit board IAR.
w.
Reinstall front and rear electronics enclosure covers.
Reinstall safety bolt cover.
x.
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