Electrical Tests; Test Gun Resistance; Test Power Supply Resistance - Graco PRO AA4500 Instructions-Parts List Manual

Electrical Tests
The performance of the spray gun is directly affected
tained inside the gun. The electrical tests below can
by the condition of the electrical COmpOnentS con-
be used to determine the condition of the power sup-
ply (18) and the barrel resistor cartridge
as
well as the
continuity of the electrical path between the compo-
nents.
CAUTION
The barrel resistor cartridge is part of the barrel
and is not replaceable. To avoid destroying
the
gun barrel, do not attempt
to
remove the barrel
age of
500
volts to complete these electrical tests.
Use
megohmmetsr 218-979 (A) and an applied volt-
Connect the leads as shown. See Accessories to .
order the megohmmeter.
WARNING
To reduce the risk of sparking, which could cause
fire, explosion, or electrostatic shock and result in
serious injury, do not use the megohmmeter in the
hazardous area. Remove the gun from the hazard-
ous area before testins
it.
Test Gun Resistance (See
Fig.
4)
trode
(1
a) and the air fitting
(I 7).
The resistance
Measure the resistance between the end of the elec-
tance is outside the specified range, go to the next
should be between 329 to 401 megotims. If the resis-
test.
if the resistance is correct, refer to Electrical
Troubleshooting on page 23 for other possible
causes of poor performance.
Test
Power Supply
Resistance (See Fig.
5)
Remove the power supply
(18)
from the gun. See
page 34.
ground contact point
(EE)
to the contact inside of the
Measure the resistance from the power supply's
power supply seal (I8e) [the conductive rubber con-
tact may be slightly recessed into
the
seau. See Fig.
5.
The resistance should be 297 to 363 megohms. If the
resistance is outside the specified range, the power
supply is defective and must be replaced.
If
the resis-
tance of the power supply
is
correct, proceed to the
next test.
Troubleshootlng for other possible causes of poor
If you still have problems, refer to Electrical
performance, or contact the nearest authorized sew-
ice agency.
NOTE: Be sure the seal (lee) is in place on the end of
the power supply before installing the power supply
back into the gun.
A
01818
Fig.
4
A
I
I
1
4
1
I
ae
18
I
Fig.
5
0141
308-294 25