Graco ULTRA 500 Instructions-Parts List Manual page 14

YPE OF PROBLEM
IOTOR W O N 7 OPERATE
iagnosing circuit board in-
mdition is red lamp on,
cator lamps. The normal
ear lamp on when board is
iling pump to run.
DIIOW Pressure Relief Pro-
dure. Remove gun from
OW.
Remove pressure con-
01 cover end check for fault
mdition of circuit board
mps.
ondition A both lamps on;
ump won't operate and
lmtor is not running
:ondition B
loth lamps off
WHAT TO CHECK
If check is OK. to to next check
I.
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 (23) and bridge
(3081
for damage
or l o o s e terminals.
3.
Check for loose motor brush lead connec-
tions and terminals. See page
2 2 .
0. Check brush length which should be 112"
minimum. See page
2 2 .
the same rate on both sides of
the
motor.
NOTE also that the brushes do not wear at
5. Check for broken or misaligned motor brush
springs. Rolled portion of spring must rest
squarely
on
top of brush. See page
22.
5. Check motor brushes for binding
in
brush
holders. See page
22.
7. Check motor armature commutator for burn
spots, gouges and extreme roughness.
Remove motor cover and brush inspection
plates to check.
See
page
22.
8. Check motor armature for shorts using er-
mature taster (growler) or perform spin
test.
See page 19.
good
bridge or performing bridge
test.
See
armature is determined to be good. A bad
CAUTION: Do not perform this check until
armature will immediately burn out a good
bridge.
1. Check circuit breaker (309) button to be sure
it
has not popped up.
9. Check bridge (308) by substituting with a
page
m.
2. Check sprayer power supply cord (311).
Disconnect TP6 female and TP1 female and
connect volt meter to these leads. Plug in
spr8yer:Meter should read 105 to 125 VAC.
Unplug sprayer. Reconnect TP1.
3. Check ON/OFF switch (303). Disconnect TP;
and connect volt meter to TP6 female and
TPZ male. Plug in sprayer and turn on. Metel
should read 105 to 125 VAC. Turn off and
unplua 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.
Meter should read 105 to 125 VAC. Turn off
and unplug sprayer. Reconnect TP3.
5. Check circuit breaker
( 3 0 9 1 .
Connect volt
meter 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 columr
Replace any loose terminals and crimp to
straight and firmly connected to mating part.
leads. Be sure male terminal blades are
Clean circuit board male terminals. Re~lace
loose or damaged terminals. Securely 'recon-
nect leads.
Tighten terminal screws. Replace brushes if
leads are damaged.
Sea
page
22.
Replace brushes. See page
22.
Replace spring if broken. Realign spring with
brush. See page
22.
Clean brush hddars. Remove carbon with
small cleaning brush. Align brush lead with
slot in brush holder to assure free vertical
brush mOVem9nt.
face commutator if possible. See page
3 0 .
Remove motor and have motor shop resur-
Replace motor. See page
30.
Replace bridge.
See
page 24.
Depress circuit breaker button to reset. If cir
trical Short", page 18.
cuit breaker continues to open, sea "Elec-
Replace power supply cord. See page
23.
Replace ON/OFF switch. Sea page
2 3 .
Replace jumper wire. See page
2 5 .
Replace circuit breaker. See page 24.
Troubleshooting continuedon nextpage
14
307-758