 |
|||
|
|
|||
|
Page Title:
Table 2-1. Troubleshooting - CONT |
|
||
| ||||||||||
|
|
 TM 10-3930-609-35
Malfunction
Probable cause
Corrective action
relay for other possible defects
(3) With 1F or 1R picked up and
wire 45 disconnected at SCR
terminal board, measure ap-
proximately 6 volts from wire
29 to wire 13A (negative) with
acceleration control near creep
speed. Voltage should drop to
zero as accelerating control is
moved toward full speed. If
readings are not correct, first
connect a jumper wire between
wire 29 and 29A which bypass-
es the thermal protector. De-
press the accelerating control
and check for the preceding
voltages. If voltage readings are
now correct, replace thermal
protector TP.
(4) If test (3) shows no voltage.
change between the two steps,
connect jumper between wires
29A and 13A. This bypasses the
accelerating control and the
truck should run at top speed.
If top speed is obtained, check
accelerating potentiometer
(5) Check 1 REC for open circuit or
Open gate (para 2-7).
(6) Test oscillator section of Card
d.
Relays IF and IR close but there is
d.
Check 2 REC for a shorted condition
very little power and high-pitch SCR
in the conducting direction (para 2-7).
hum.
e.
Relays IF and IR close but very little
e.
With drive wheels of truck of the
or no power with low SCR hum, even
floor, make the following tests:
when accelerating control is in top
(1) Disconnect wires 1 and 5 from
SCR position.
SHUNT (sensor). Reapply pow-
er. If accelerating control now
operates normally, replace Card
1. Remove card from panel (fig.
bottom and pulling box straight
up to disengage from receptacle.
(2) If accelerating control does not
operate normally in test (1),
check oscillator section of Card
f.
Check 3 REC for open condition
f.
Relays IF and IR close, SCR hum is
normal, but there is very little power.
check 1, 2, and 5 REC for proper
operation (para 2-7). If 3 REC is
satisfactory, check 4 REC for short-
ed condition (para 2-6).
Check motor, remove and repair as
2. No travel motor torque in SCR
If none of the preceding travel motor
required (para 3-80 through 3-86)
range or with relay 1A closed.
may be defective.
(1) Check potentiometer for proper
3. Full travel motor torque with SCR
a.
Relays IF and IR close with full
resistance (para 2-5).
control (relay 1A open).
SCR speed immediately and audible
hum.
2-5
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals