Graco Inc. 307-638 Paint Sprayer User Manual


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16 307-638
ELECTRICAL TESTS
The performance of the spray gun is directly affected by
the condition of the electrical components contained inĆ
side the gun. The electrical tests below can be used to
determine the condition of the power supply (5) and the
resistor stud (16) as well as the continuity of the electriĆ
cal path between the components.
Use megohmmeter 218-979 (see ACCESSORIES)
and an applied voltage of 500 volts to complete these
electrical tests. Connect the leads as shown.
ăWARNINGĂ
To reduce the risk of sparking, which could cause
fire orexplosion andresult in seriousbodily injury,
DO NOT use the megohmmeter in the hazardous
area. Remove the gun from the hazardous area
before testing it.
Test Gun Resistance
NOTE: Check the resistancewith the gun triggered and
untriggered.
Measure the resistance between the end of the elecĆ
trode (12) and the gun air fitting (2a). See Fig 7. The reĆ
sistance should be between 115-152 megohms. If the
resistance is outside the specified range, go to the next
test. If th e resistance is correct, refer to the Electrical
Troubleshooting Chart on page 15 for other possible
causes of poor performance.
Test Power Supply Resistance
Remove thepower cartridge(3) from thegun handle (2).
See Power Cartridge Replacement.
Remove the turbine alternator (3a) from the power supĆ
ply (5). See Turbine Alternator Removal.
Measure the resistance from the center prong (EE) in
the power supply to the contact spring (5c) on the other
end of the power supply. See Fig 8.
The resistance should be 95-122 megohms. If the reĆ
sistance is outside the specified range, the power supĆ
ply isdefective and mustbe replaced.If theresistance of
the power supply is correct, proceed to the next test.
If you still have problems, refer to the Electrical
Troubleshooting Chart for other possible causes of
poor performance, or contact the nearest authorized
service agency.
Fig 7
KEY
A Megohmmeter
2 Gun Handle
2a Air Fitting
12 Electrode
Fig 8
KEY
A Megohmmeter
EE Connector Center Prong
5 Power Supply
5c Contact Spring
2a
12
A
A
5c
5
EE
2
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