Graco ULTRA 500 Instructions-Parts List Manual page 13

MOTOR WON'T OPERATE (Continued)
TYPE OF PROBLEM
Follow Pressure Relief Proce-
dure on page 13. Remove gun
from hose. Remove pressure
control.
Refer to the wiring diagram
on page 35 to identify test
points (TP).
WHAT TO CHECK
If check is OK, go to next check
1 . Check leads from motor to be sure they are
securely fastened and properly mated.
2. Check for loose motor brush lead connections
and terminals. See page 19.
3. Check brush length which should be 12 mm
(1/2 in.) minimum. See page 19.
NOTE: The brushes do not wear at the same
rate on both sides of the motor . Check both
brushes.
4. Check for broken or misaligned motor brush
springs. Rolled portion of spring must rest
squarely on top of brush. See page 19.
5. Check motor brushes for
holders. See page 19.
6. Check motor armature commutator for burn
spots, gouges and extreme roughness. Re-
move motor cover and brush
plates to check. See page 19.
7. Check motor armature for shorts using arma-
ture tester (growler) or perform spin test. See
page 16.
8. Check pressure control board (301) by substi-
tuting with a good pressure control board. See
page 22.
9. Check filter board. Connect volt meter to TP7
and ON/Off switch TP3.Connect a jumper
from TP4 to TP8. Plug in sprayer
should read 200 to 250 VAC. Unplug sprayer.
Remove jumper.
1. Check power supply cord (314). Disconnect
TP1 female (neutral) and TP2 female and
connect volt meter to these leads. Plug in
sprayer. Meter should read 200 to 250 V AC.
Unplug sprayer. Reconnect TP2.
2. Check ON/OFF switch (307). Disconnect TP3
and TP4 and connect volt meter to TP3 and
TP4 terminal on the ON/OFF switch. Plug in
sprayer and turn ON. Meter should read 200
to 250 VAC. Turn off and unplug sprayer. Re-
connect TP3.
3. Check motor terminal cutoff switch. Connect
volt meter to TP1 female and TP6 female.
Plug in sprayer and turn on. Meter should read
200 to 250 VAC. Turn off and unplug sprayer.
4. Check all terminals for damage or loose fit.
Reconnect TP1, TP2, TP3, TP4, TP5, and
TP6 connectors.
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.
Clean circuit board male terminals. Re-
place loose or damaged terminals. Se-
curely reconnect leads.
2. Tighten terminal screws. Replace brushes
if leads are damaged. See page 19.
3. Replace brushes. See page 19.
4. Replace spring if broken. Realign spring
with brush. See page 19.
binding in brush 5. Clean brush holders. Remove carbon with
small cleaning brush. Align brush leads
with slot in brush holder to assure free verti-
cal brush movement.
6. Remove motor and have motor shop resur-
face commutator if possible. See page 26.
inspection
7. Replace motor. See page 26.
8. Replace with new pressure control board
(301). See page 22.
9. Temporary bypass to check (Replace filter
board?)
. Meter
1. Replace power supply cord. See page 20.
2. Replace ON/OFF switch. See page 21.
3. Allow motor to cool. Correct cause of over-
heating. If switch remains open after motor
cools, check continuity between TP4 fe-
male and TP5 female with ohmmeter . If
open, replace motor.
4. Replace damaged terminals and recon-
nect securely.