Control Board Diagnostics - Graco G-Max 7900 Instructions Manual

Control Board Diagnostics

1. Remove five screws (307) and cover (322) (F
2. Start sprayer.
LED Blinks
Two times Sprayer shuts down and LED
repeatedly continues to blink two times
repeatedly
Three times Sprayer shuts down and LED
repeatedly continues to blink three times
repeatedly
Four times Sprayer shuts down and LED
repeatedly continues to blink four times
repeatedly
Five times Sprayer shuts down and LED
repeatedly continues to blink five times
repeatedly
Six times Sprayer shuts down and LED
repeatedly continues to blink six times
repeatedly
308870G
Sprayer Operation
. 22). 3. Turn ON/OFF switch ON.
IG
4. Observe LED operation and reference following
table:
Indicates
Run away pressure.
Pressure greater than
4500 psi (310 bar, 31
MPa)
Pressure transducer is
faulty or missing
Generator voltage is
low
High clutch current
High clutch tempera-
ture
Pressure Control
What to do
1. Check pressure transducer con-
nection at control board.
2. Replace pressure transducer.
3. Replace control board.
1. Check pressure transducer con-
nection at control board.
2. Replace pressure transducer.
3. Replace control board.
1. Increase engine throttle.
2. Check wiring connections.
3. Service Honda engine alternator.
1. Check clutch 5-pin bulkhead con-
nector. Clean contacts.

2. Measure 1.7 +0.2
clutch field at 70°F (21°C).
3. Replace clutch field assembly.
1. If clutch is new, let sprayer cool
down and then restart
2. Inspect clutch. Replace clutch if
there is excessive wear.
3. Remove pump pin, separate pin-
ion housing from clutch housing.
Rotate rotor clockwise to check
for excessive drag.
across
21