Graco A Series Instructions-Parts List Manual page 18

MOTOR WON'T OPERATE
TYPE OF PROBLEM
Condition B (continued)
Both lamps off
REFER T O THE WIRING
DIAGRAM ON BELOW
TO IDENTIFY TEST
POINTS (TP).
WIRING DIAGRAM
TP16
WHITE
YELLOW
BLACK
NOTE: These leads have
interchangeable
connections:
TP9 and TP10
TP13 and TP14
TP15 and TP16
Condition C
Red lamps on,
Clear lamp off
Unplug sprayer!
307–958
WHAT TO CHECK
If check is OK, go to the next check.
7. Check microswitch (302).Reconnect TP6
connectors. Connect volt meter to TP15
male and TP4. Meter should read 50–125
VAC.
8. Visually inspect microswitch (302) button.
Adjustment stud should not depress the
button when fluid pressure is zero. Manu-
ally check by depressing button with small
screwdriver; an audible click
microswitch is in normal position.
9. Check microswitch (302) continuity with
ohm meter. Be sure sprayer is unplugged!
Meter should read zero ohms with no fluid
pressure in the sprayer.
10. Check all terminals for damage or loose
fit. Reconnect TP6 connectors.
11. Check circuit board (74) by substituting
with a good board. See page 28.
303
TP1
TP15
302
BLUE
RED
TP6
TP14
TP7
TP13
BLACK
GREEN
GROUND
WIRE
POWER SUPPLY CORD
1. Check circuit board (74) by removing
from without disconnecting wires; see
page 28 for removal procedure.
WARNING: Removing the circuit
while still wired over–rides the optical detec-
tor which could cause the sprayer to over–
pressurize, if the microswitch does not func-
tion properly. Turn the sprayer on ONLY long
enough to check lamp condition, then shut off
immediately.
WARNING: To reduce the risk of electric
shock, handle board by edges only! Do not
allow any metal objects to touch the board!
Plug in and turn on sprayer. Clear lamp
should be on now – removing the circuit
board over–rides the optical detector .
Turn off and unplug the sprayer.
2. Check bourdon tube flag and detector
position. Reinstall circuit board (see
page 28. Turn pressure setting to maxi-
mum; flag should extend less than half
way into optical detector slot from the
bottom.
WHAT TO DO
If check is not OK, refer to this column.
7. Clean microswitch male terminals. Re-
place loose or damaged terminals. Se-
curely reconnect leads.
8. Microswitch is faulty. Return sprayer for
repair.
indicates
9. Microswitch is faulty. Return sprayer for
repair.
10. Replace damaged terminals and recon-
nect securely.
11. Replace circuit board. See page 28.
309
TP2
TP3
306
TP4
TP10
TP9
308
MOTOR
LEADS
WHITE
TP8 MOTOR
THERMAL SWITCH
1. Replace circuit board. See page 28.
board
DETECTOR
CIRCUIT
2. Adjust pressure control to see if that cor-
rects problem. See page 30.
If not, replace pressure control (301).
See page 29.
FLAG
OPTICAL
BOARD