Lincoln Electric COMMANDER 400 SVM133-B Service Manual page 88

F-34
TEST PROCEDURE
1. Turn the engine off.
2. Unlatch, lift and secure the right side engine
service access door. Using a 5/16", open
the control panel and tilt out. Remove the
control board cover.
3. Check the pull-in coil resistance by discon-
necting lead #227 from the B1 terminal at
the control board and measuring the resis-
tance from lead #227 to the ground screw at
the control board. Normal coil resistance is
approximately 0.4 ohms. Reconnect lead
#227 to the B1 terminal at the control board.
Check the hold-in coil resistance by discon-
necting J3 from the control board and mea-
suring across pins 3 & 4. Normal coil resis-
tance is approximately
Reconnect J3 at the control board.
If either coil resistance is incorrect, the
wiring may be faulty. Inspect the solenoid
leads for faulty or loose connections.
If the lead connections are OK, recheck the
coil resistance directly across the solenoid.
If the coil resistances are incorrect, the
solenoid may be faulty. Replace.
4. Using the external 12VDC voltage supply,
apply 12VDC to the larger idler solenoid ter-
minals (#227+ to #254-).
should activate.
TROUBLESHOOTING & REPAIR
IDLER SOLENOID TEST (continued)
FIGURE F.8 – IDLER SOLENOID LEAD TERMINALS
SHUTDOWN
SOLENOID
20 ohms.
The solenoid
COMMANDER 400
PULL-IN COIL
(LARGER TERMINALS
TOP AND BOTTOM
#227 AND #254)
IDLER
SOLENOID
CAUTION
When the solenoid activates, remove the voltage
supply immediately. Do not leave the external
supply connected to terminals #227 and #254 for
longer than three seconds. Component damage
could result.
The solenoid should deactivate when the
12VDC supply is removed.
5. If the solenoid does not operate properly,
check for a mechanical restriction in the
linkage.
6. Using the external 12VDC voltage supply,
apply 12VDC to the smaller idler solenoid
terminals for the hold-in coil (#226+ to #237-).
Push in the solenoid plunger. With 12VDC
applied to the hold-in coil, the plunger
should stay in until the 12VDC is removed.
7. If the linkage is intact and the solenoid does
not operate correctly when 12VDC is applied,
the solenoid may be faulty. Replace.
8. Replace the harness leads to the correct
terminals. See Figure F. 8 and the Wiring
Diagram. Replace any previously removed
wire wraps.
8a. Using the control PC board layout, locate
Q21 on the control board. Scrape the envi-
ronmental coating from all three legs of the
device, and check the resistance between
all three legs. If there is continuity between
any of the legs, Q21 is bad. Replace the
control PC board.
9. Close and secure the right side engine ser-
vice access door. Replace the control board
and close the control panel.
F-34
HOLD-IN COIL
(SMALLER
TERMINALS
TOP AND BOTTOM
#226 AND #237)