307671D ULTRA 400 AIRLESS PAINT SPRAYER - Graco Inc.

TYPE OF PROBLEM
ELECTRICAL SHORT
WHAT TO CHECK
If check is OK, go to next check
WHAT TO DO
If check Is NOT OK refer to this column
Buildino circuit breaker ooens
as sooi as sprayer switch is
turned on.
CAUTION
Any short in any part of thf
motor power circuit, which i$
connected to the output sidc
of the bridge, will cause thf
bridge to burn out immediate
ly. Correctly diagnose anc
repair all shorts before check,
ing and replacing bridge
Building circuit breaker opens
as soon as sprayer is plugged
into outlet and sprayer is NO1
turned on.
Check all electrical wiring for damaged
insulation, and all terminals for loose fit
or damage. Be sure to check wires between
pressure control and motor which
are encased in conduit 141 I. See page
29.
1. Repair or replace any damaged wiring or
terminals. Securelv reconnect all wires.
, Check for missing inspection plate 2. Correct faulty conditions.
gasket (see page 27). bent terminal forks
or other metal to metal contact points
which could cause a short.
Check motor armature for shorts by us- 3. Replace motor. See page 29.
ing an armature tester (growler) or perform
spin test. See page 15. Inspect
windings for bums.
, Check bridge ( 3081 by substituting with 4. Replace bridge. See page 2 0.
a good bridge or by performing bridge
test. See page 16.
CAUTION: Do not perform this check
until armature is determined to be good.
A bad armature will immediately burn
out a good bridge.
Check 'Basic Electrical Problems' on
page 9.
Check ON/OFF switch 1302) See page
19. Be sure the sprayer is unplugged!
Disconnect wires from switch and check
switch with ohm meter. The ohm meter
should read infinity with the ONlOFF
switch OFF, and zero with the switch
ON.
2. Replace ON/OFF switch. See page 19.
CAUTION: A short in the motor circuit
will burn the bridge out immediately,
which in turn usually causes the ONlOFF
switch to fail in the closed mode.
14 307-671