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MOTOR WON'T OPERATE
TYPE OF PROBLEM
Diagnosing circuit board
indicator lamps. The normal
condition is red lamp on, clear
lamp on when board is telling
pump to run.
Follow Pressure Relief Pro-
cedure Warning. Remove
gun from hose. Remove pres-
sure control cover. Check for
faulty condition of circuit
board lamps.
Condition A
Both lamps on; pump won't
operate and motor is not
running
Condition B (continued)
Both lamps off
REFER TO THE WIRING
DIAGRAM ON PAGE 18
TO IDENTIFY TP POINTS.
NOTE: Connect the volt meter
to the terminal not the wire
which you disconnect from the
terminal.
WHAT TO CHECK
If check is OK, go to next check
1 . Check leads from bridge (308) to motor to be
sure they are securely fastened and properly
mated.
2. Check G1 and G2 connections between cir-
cuit board (72) and bridge (308) for damage or
loose terminals.
3. Check for loose motor brush lead connec-
tions and terminals. See page 25.
4. Check brush length which should be 1/2"
minimum. See page 25.
NOTE: The brushes do not wear at the same
rate on both sides of the motor. Check both
brushes.
5. Check for broken or misaligned motor brush
springs. Rolled portion of spring must rest
squarely on top of brush. See page 25.
6. Check motor brushes for binding in brush
holders. See page 25.
7. Check motor armature commutator for burn
spots, gouges and extreme roughness. Re-
move motor cover and brush inspection
plates to check. See page 25.
8. Check motor armature for shorts using arma-
ture tester (growler) or perform spin test. See
page 22.
9. Check bridge (308) by substituting with a
good bridge or performing bridge test. See
page 23.
CAUTION: Do not perform this check until
motor armature is determined to be good. A
bad motor armature will immediately burn out
a good bridge.
1. Check circuit breaker (309) button to be sure
it has not popped up.
2. Check power supply cord (311). Disconnect
TP6 female (neutral) and TP1 female and
connect volt meter to these leads. Plug in
sprayer. Meter should read 105 to 125 VAC.
Unplug sprayer. Reconnect TP1.
3. Check ON/OFF switch (303). Disconnect TP2
and connect volt meter to TP6 female and
TP2 male. Plug in sprayer and turn ON. Meter
should read 105 to 125 VAC. Turn off and un-
plug sprayer. Reconnect TP2.
4. Check jumper wire (306). Disconnect TP3
and connect volt meter to TP6 female and
TP3 female. Plug in sprayer and turn on. Me-
ter should read 105 to 125 VAC. Turn off and
unplug sprayer. Reconnect TP3.
5. Check circuit breaker (309). Connect volt me-
ter to TP6 female and TP4. Plug in sprayer
and turn ON. Meter should read 105 to 125
VAC. Turn off and unplug sprayer.
WHAT TO DO
When check is not OK refer to this column
1. Replace loose terminals; crimp to leads.
Be sure male terminal blades are straight
and firmly connected to mating part.
2. Clean circuit board male terminals. Re-
place loose or damaged terminals. Se-
curely reconnect leads.
3. Tighten terminal screws. Replace brushes
if leads are damaged. See page 25.
4. Replace brushes. See page 25.
5. Replace spring if broken. Realign spring
with brush. See page 25.
6. Clean brush holders. Remove carbon with
small cleaning brush. Align brush leads
with slot in brush holder to assure free verti-
cal brush movement.
7. Remove motor and have motor shop resur-
face commutator if possible. See page 34.
8. Replace motor. See page 34.
9. Replace bridge. See page 23.
1. Depress button to reset. If circuit breaker or
fuse continues to open, see "Electrical
Short", page 21.
2. Replace power supply cord. See page 26.
3. Replace ON/OFF switch. See page 26.
4. Replace jumper wire. See page 26.
5. Replace circuit breaker. See page 27.
17
307–758
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