Graco 231-081, Instructions And Parts List

17

307–920

Diagnosing circuit board in–

dicator lamps. The normal con-

dition is red lamp on, clear lamp

on when board is telling pump

to run.

Follow 

Pressure Relief Proce-

dure Warning

. Remove gun

from hose. Remove pressure

control cover and check for

faulty condition of circuit board

lamps.

Condition A

Both lamps on; pump

won’t operate and motor

is not running

1. Check leads from bridge (308) to motor to

be sure they are securely fastened  and

properly mated.

2. Check G1 and G2 connections  between

circuit board (23) and bridge (308) for dam-

age or loose terminals.

3. Check for loose motor brush lead connec-

tions and terminals. See page 25.

4. Check brush length which should be 1/2”

minimum. See page 25. 

NOTE: 

The brushes do not wear at the

same rate on both sides of the motor

.

Check both brushes.

5. Check for broken or misaligned motor

brush springs. Rolled portion of spring must

rest squarely on top of brush. See page 25.

6. Check motor brushes for binding in brush

holders. See page 25.

7. Check motor armature commutator for

burn  spots,  gouges and extreme rough-

ness. Remove motor cover and brush in-

spection plates to check. See page 25.

8. Check motor armature for shorts using ar-

mature tester (growler) or perform spin test.

See page 22.

9. Check bridge (308) by substituting with a

good bridge or performing bridge test. See

page 23.

CAUTION:

 Do not perform this check until ar-

mature is determined to be good. A bad ar-

mature will immediately burn out a good

bridge.

1. Replace loose terminals; crimp to leads. Be

sure male terminal blades are straight and

firmly connected to mating part.

2. Clean circuit board male terminals. Re-

place loose or damaged terminals. Se-

curely reconnect leads.

3. Tighten terminal screws. Replace brushes

if leads are damaged. See page 25.

4. Replace brushes. See page 25.

5. Replace  spring  if broken. Realign spring

with brush. See page 25.

6. Clean brush holders. Remove carbon with

small cleaning brush. Align brush leads

with slot in brush holder to assure free verti-

cal brush movement.

7. Remove motor and have motor shop resur-

face commutator if possible. See page 34.

8. Replace motor. See page 34.

9. Replace bridge. See page 27.

MOTOR WON’T OPERATE

WHAT TO CHECK

If check is OK,  go to the next check.

TYPE OF PROBLEM

WHAT TO DO

 If check is not OK, refer to this column.

1. Check circuit braker (309) button to be sure

it has not popped up.

2. Check power supply cord (31 1). Discon-

nect TP6 female and TP1 female and con-

nect volt meter to these leads. Plug 

in

sprayer. Meter should read 105 to 125

VAC. Unplug sprayer. Reconnect TP1.

3. Check ON/OFF switch (303). Disconnect

TP2 and connect volt meter to TP6 female

and TP2 male. Plug in sprayer and turn on.

Meter should read 105 to 125 VAC. Turn off

and unplug sprayer. Reconnect TP2.

4. Check jumper wire (306). Disconnect TP3

and connect volt meter to TP6 female and

TP3 female. Plug in sprayer and turn on.

Meter should read 105 to 125 VAC. Turn off

and unplug sprayer. Reconnect TP3.

5. Check circuit breaker (309). Connect volt

meter to TP6 female and TP4.  Plug in

sprayer and turn on. Meter should read 105

to 125 VAC. Turn off and unplug sprayer.

6. Check motor thermal cutout switch. Con-

nect volt meter to TP6 female and TP9 fe-

male.  Plug in sprayer and turn on. Meter

should read 105 to 125 VAC. Turn off and

unplug sprayer.

Condition B 

(continued)

Both lamps off
REFER TO THE WIRING

DIAGRAM ON PAGE 19

TO IDENTIFY TEST

 POINTS (TP).

1. Depress button to reset. If circuit breaker

or fuse continues to open, see “Electrical

Short”, page 21.

2. Replace power supply cord. See page 26.

3. Replace ON/OFF switch. See page 26.

4. Replace jumper wire. See page 28.

5. Replace circuit breaker. See page 27.

6. Allow motor to cool. Correct cause of over-

heating. If switch remains open after mo-

tor cools, check continuity between  TP9

female and TP10 with ohmmeter. If open,

replace motor.