Graco Finishpro 390 User manual

Rev. B 10/11 /07
WARNING
This manual should only be used
by a qualified Service Technician.
FinishPro™ 390/395
Airless/Air-Assisted Sprayer
Repair Electrical Manual
--
��
Black
Red
Yel
Yel
3.00
First choice when
quality counts.
ti9026a
FinishPro 395
FinishPro 390
ti9019a
Exhaust Port
Air Hose
Connection

Table of Contents
Basic meter terminology and testing procedures................................................................................................. 3-9
Error Code Chart ............................................................................................................................................. 26-32
FinishPro 390
ON/OFF Switch Test ............................................................................................................................................ 10
Switch Ladder Diagram.........................................................................................................................................11
288841Control board:
• Airless Motor will not start................................................................................................................. 12,13
• Airless Motor Test................................................................................................................................... 14
• Airless Motor will not shut off ................................................................................................................ 15
Air Compressor
• Air Compressor will not start .................................................................................................................. 16
• Air Compressor runs but will not build pressure..................................................................................... 17
• Air Compressor is trying to start (humming). ......................................................................................... 10
FinishPro 395
ON/OFF Switch Test ....................................................................................................................................... 18,19
Switch Ladder Diagram.........................................................................................................................................20
288841Control board:
• Airless Motor will not start..................................................................................................................21,22
• Airless Motor Test................................................................................................................................... 23
• Airless Motor will not shut off ................................................................................................................ 24
Air Compressor
• Air Compressor will not start ...................................................................................................................25
• Air Compressor runs but will not build pressure..................................................................................... 26
• Air Compressor is trying to start (humming). .................................................................................... 18,19

BASIC ELECTRICAL TERMINOLOGY
In any discussion of electricity, there are three basic terms you will need to understand.
CURRENT
VOLTAGE
RESISTANCE
CURRENT:
Current is the movement of the electrical charge.
Current Flows through the wires from the power source to the load.
Current is measured in AMPERES (AMPS, A or I). See Figure 1.
NOTE: Meter is only clamped around one wire.
VOLTAGE:
Voltage is the force that causes current to fl ow in a circuit.
Voltage is measured in VOLTS (V or E). See Figure 2.
FIGURE 1
FIGURE 2
ON/OFF
Switch
Ref 58
Power
Plug
Red (+)
White
Black
Green
Black (–)
Black
from Motor
ON/OFF
Switch
Ref 58
Power
Plug
Potentiometer Ref 37
Red (+)
White
Black
Green
Black (–)
Black
120 AC
V
Motor
3

BASIC ELECTRICAL TERMINOLOGY
RESISTANCE:
Resistance is anything that causes an opposition to the fl
ow of current in a circuit.
Resistance is used to control the amount of voltage and/or amperage in a circuit.
Resistance is measured in OHMS - Ω. See Figure 3.
A common component check would be motor and clutch field windings.
FIGURE 3
--
��
Black
Red
Yel
Yel
Known Value
��
Known Value
+
-
4

CONTINUITY TESTING
Checking “continuity” is one of the most common tests in electrical troubleshooting. Continuity is the ability of a wire or electrical component to
conduct current. When you use a continuity tester, you connect a circuit (the continuity tester) that you know works, to a wire or a component that
may or may not work. The continuity tester will tell you if the wire or component is capable of conducting current.
Continuity testers are available at almost any hardware store.
A volt-ohmmeter or VOM can also be used to check continuity. This meter can be purchased at most electrical or electronic supply stores.
To test a component for continuity:
1 Check the tester by connecting the leads.
* If using a test light the light should turn on.
* If using a digital volt-ohmmeter, the screen should show 00 if OL appears the meter needs to be repaired.
SWITCH TESTING-ROCKER
Common test procedure for a SPST Switch:
0.000
5

WIRE CONTINUITY TESTING
Continuity testing will “NOT” fi
nd wire fragmentation!!
Example:
120 Vac input static voltage and drops to 119Vac load voltage.
A good piece of wire will carry line and load voltage.
Damaged / Fragmented Wire Damaged / Fragmented Wire
Pinched Wire
120 Vac input static voltage and drops to 76Vac load voltage.
Other causes:
Poor stripping of outer insulation.
Poor crimp.
A defective piece of wire may carry line voltage but will “NOT” carry load voltage
6

GROUND TESTING
Every corded electric sprayer that comes into your shop for repair should be tested as described below, to make sure that it is properly grounded.
Pull the machine’s plug out of the wall outlet and connect one lead from a DC continuity test light or a VOM to the (round) ground terminal on the
plug.
NOTE:
If the ground terminal is broken off of the plug, install a new plug.
Touch the test light (or VOM) leads to several bare metal surfaces on the body of the machine. If the light (or meter) indicates continuity, the machine
is properly grounded. If the light (or meter) doesn’t indicate continuity trace through the ground (green) wiring on the machine to determine where
the break is.
Improper installation or alteration of grounding plug could results in risk of electric shock, fire or explosion that could cause serious injury or death.
The other function of the grounding plug is to protect the control board from static build up. If the plug is missing this could cause permanent damage
to the control board.
7

CAPACITOR TESTING:
A capacitor is an electrical component that stores electricity. Capacitors are usually used to help start a motor or make a motor run more efficiently.
The following instructions can be used to test any capacitor.
WARNING!
A CAPACITOR CAN SHOCK YOU EVEN WHEN A MACHINE IS UNPLUGGED. NEVER TOUCH CAPACITOR TERMINALS WITH
YOUR FINGERS. ALWAYS USE TOOLS WITH INSULATED HANDLES. NEVER DISCHARGE A CAPACITOR NEAR FLAMMABLE
LIQUIDS OR VAPORS.
1 Visually inspect the capacitor for leaks, mechanically damage or loose terminals. Replace it if any of these problems exist.
2 Unplug the machine and remove the capacitor(s).
If capacitor(s) are attached to the control board the test can not be perormed.
3 “SEE ABOVE WARNING” Using a screwdriver with
insulated handles, hold so that the blade contacts the
capacitor terminals as shown in Fig. A. This will
“discharge” the capacitor.
4 Put a volt-Ohm meter on the R X 100 scale.
5 While watching the meter, connect the 2 leads to the 2 terminals on the capacitor.
If the capacitor is good, the meter needle will go to the right (toward 0 resistance) (Fig. 1), then to the left (toward - maximum resistance)
If the meter needle goes all the way to the right and stays there, the capacitor is defective.(Fig.2)
If the meter needle stays all the way to the left (doesn't move at all when connected to the capacitor), the capacitor is defective.(Fig. 3)
FIG. A
Capacitor
GOOD BAD BAD
8

RECTIFIER
(See Fig. 1) Now we come to the most popular application of the diode: rectifcation. Rectifcation is the conversion of alternating
current (AC) to direct current (DC). This almost always involves the use of some device that only allows one-way fl ow of electrons.
As we have seen, this is exactly what a diode does.
RECTIFIER TESTING:
The following instructions can be used to test any bridge rectifer.
Use a DC continuity test light or a VOM (on the R x 100 scale) for all tests.
Disconnect all wires from the rectifer.
AC
AC
+
-
FIG. 1
1 Connect test leads as shown in Figure A. If the meter beeps, the rectifer is
defective. If the meter does not beep, go to the next step.
2 Connect test leads as shown in Figure B. If the meter does not beep, the
rectifer is defective. If the meter beeps, go to the next step.
3 Connect test leads as shown in Figure C. If the meter beeps, the rectifer is
defective. If the meter does not beep, go to the next step.
4 Connect test leads as shown in Figure D. If the meter does not beep, the
rectifer is defective. If the meter beeps, go to the next step.
5 Connect test leads as shown in Figure E. If the meter beeps, the rectifer is
defective. If the meter does not beep, go to the next step.
6 Connect test leads as shown in Figure F. If the meter does not beep, the rectifer is defective. If the meter beeps, go to the next step.
7 Connect test leads as shown in Figure G. If the meter beeps, the rectifer is defective. If the meter does not beep, go to the next step.
8 Connect test leads as shown in Figure H. If the meter does not beep, the rectife r is defective. If the meter beeps, the rectifer is good.
0.000
OL OL 0.000
0.000
OL OL 0.000
FIG. A FIG. B FIG. C FIG. D
FIG. E FIG. F FIG. G FIG. H
DC DC
9

FinishPro 390
ON/OFF Switch Test
Compressor
AA Mode
Airless Mode
Off
Step 1
++
Power switch in
the Airless Mode.
Cord plugged in.
Meter on AC Volts
FUSE
F1
J4
Control
Board
110-120 AC
V
--
--
J3
Power switch in
the AA Mode.
Cord plugged in.
Meter on AC Volts
Power switch in
the AA Mode.
Cord plugged in.
Meter on AC Volts
NO
See step 2. Do you have
over 100 AC volts?
YES
See step 1.Do you have
over 100 AC volts?
YES
Check the connector
for the white wires.
If ok repair or replace
the power Cord.
Replace the
power switch.
Switch is good. Proceed to the proper Test Section
NO
See step 3.Do you have
over 100 AC volts? NO
YES
Replace the
power switch.
Connector
Power
Plug
Compressor
AA Mode
Airless Mode
Off
Step 2
FUSE
F1
J4
Control
Board
110-120 AC
V
--
--
J3
Connector
Power
Plug
Compressor
AA Mode
Airless Mode
Off
Step 3
FUSE
F1
J4
Control
Board
110-120 AC
V
--
--
J3
Connector
Power
Plug
++
++
Airless Motor will
not sart. See Control
Board Test Section
Compressor Motor will
not sart. See Compressor
will not start Test Section.
10

Compressor Power
Cord
F1
Control Board
Compressor Power
Cord
F1
Control Board
Compressor Power
Cord
F1
Control Board
Airless
OFF
Air-Assisted
Airless Mode
Switch Down
Air Assisited Mode
Switch Up
Off
Switch Center
FinishPro™ 390 Switch Ladder Diagram
White White
White White
White White
White White
Black Black
Black
Black
Black Black
Black
Black
Black Black
Black
Black
11

NO
If motor is hot, let
cool and retest, if
step 4 still shows an
open replace motor.
The motor has a
defective
thermistor switch.
See pages 12 for the steps and illustrations.
NO
See step 4.
Is there
continuity
through the
thermistor
wires?
See step 5
Does the
motor run?
See Motor Test
YES
See step 1.
Do you have
over 100 AC
volts?
YES
See step 3.
Is there over
100 DC volts?
YES
YES
See ON/OFF
Switch Test
.
NO
Replace
Pressure Switch
Replace Control Board.
No
FinishPro 390
288841 Control Board
Airless Motor will not run
See step 2. Do
you have over
100 AC volts?
NO
YES
Is the fuse open?
Replace Control Board.
No
Before replacing
the fuse check
the motor for a short.
YES
12

Blk
Red
Yellow
Control
Board
100 + DC
V
Step 3
Cord plugged in.
Switch ON.
Pressure Switch
Turned to high.
Meter on DC volts.
--
--
J1
Step 5
Motor plugged in.
Cord plugged in.
Switch ON.
Pressure switch
unplugged.
Control
Board
Insulated Jumper wire
stripped on the ends
J3
J4
Control
Board
To
Power Cord
Step 1
Cord plugged in.
Switch ON.
Wires connected
to control board.
Meter on AC Volts
110-120 AC
V
--
--
++
��
BEEP
Checking the motor
thermistor switch .
Unplug the motor
wires from control
board.
Carefully insert the
meter probes into the
2 yellow wires.
Meter should read
continuity.
Note: motor should be
cooled down.
++
Yellow
--
Step 4
Red
Blk
FUSE
To Compressor
ON/OFF
Switch
Power
Plug
Pressure
Control
Assembly Motor
Replaceable Fuse
Black (-)
Red (+)
2X Yellow
Green
White
Black
FUSE
F1
J4
Control
Board
Step 2
Cord plugged in.
Switch ON.
Wires connected
to control board.
Meter on AC Volts
110-120 AC
V
--
--
++
FinishPro 390
261779 Control Board
Airless Motor will not run
13

249040 Motor Test
1. Remove the pump pin and try to run the sprayer. If the motor runs check for locked or frozen pump
or drive train. If sprayer does not run, go to next step.
2. Set sprayer to OFF and disconnect power to sprayer .
3. Disconnect motor connector from control board. Check the motor connector and
control board contacts. They must be clean and secure. Reconnect motor connector
to control board socket(s). Turn the pressure knob clockwise a ½ turn. Try to restart the motor.
If motor does not run follow the steps below.
Step 1
Step 2
Step 4
Checking the motor wires for a short.
Put the (+) meter lead on the motor case.
Move the (-) meter lead to each wire.
Meter should read open on all the wires.
Perform a spin test by connecting a 9 volt
battery or larger to the motor leads. Spin the motor while checking.
If a open is found replace the motor.
Step 3
Checking the motors thermal protection.
Meter should read continuity.
Note: motor should be cooled down.
Use CAUTION not to distort the connectors when inserting the meter probes.
Blk
Red
Yel
Yel
+
-
9 volt
battery
--
��
1-3 ohms
Blk
Red
Yel
Yel
++
--
��
BEEP
--
Blk
Red
Yel
Yel
++
--
Blk
Red
Yel
Yel
++
--
��
OL
--
14

YES
Motor will not shut off:
Unplug sprayer turn the
prime/spray valve to the prime
position. Plug sprayer in, once
material comes out of the prime
drain hose turn the prime/spray
valve to spray. Does fluid stop
for a moment and then come
though?
NO
Defective pressure
control switch.
Replace.
Unplug sprayer turn the
prime/spray valve to the
prime position. Plug sprayer
in, once material comes out
the prime drain hose turn
the prime/spray valve to
spray. Does fluid continue
to flow though the drain
hose?
Check the Inlet and Out
valves for a stuck ball,
See freeing up inlet and
outlet check valves. If
ok check the packing
for wear or damage,
replace if needed.
Defective Prime
Spray Valve.
Replace.
Put the sprayer in the prime
position. Remove the control
board cover, turn the sprayer
on and then unplug the
pressure control switch. Does
the motor stop running
NO
NO
YES
YES
Defective control
board. Replace.
FinishPro 390
Control Board 261779
15

To Compressor
Power
Plug
Green
White
Black
Control Board
Connector
Compressor
Air Solenoid (N/O).
When the compressor is ON,
voltage is present.
When the compressor is OFF,
voltage is NOT present.
AA Mode
Airless Mode
Off
Power switch in
the AA Mode.
Cord plugged in.
Meter on AC Volts
Compressor
AA Mode
Airless Mode
Off
Step 1
J4
Control
Board
110-120 AC
V
--
--
J3
Connector
Power
Plug
++
To
NO
See step 1. Do you have
over 100 AC volts?
YES
Does the airless
motor run?
YES
See ON/OFF
Switch Test section
Replace the
power switch.
NO
Replace the
compressor.
Is the compressor
trying to start?
(Humming)
NO
See Air Compressor
Will not build
pressure section.
YES
390 FinishPro
Air Compressor will not start.
16

Air Solenoid (N/O).
Closed when the compressor is on.
Open when compressor is off.
With the solenoid open, the air
pressure will exhaust and allow the
compressor to start.
Exhaust Port
Air Hose
Connection
32psi. Pressure
Relief Valve.
The valve will open when the
compressor builds over 32psi.
This is a normal function.
NO
YES
NO
Replace the
compressor.
Is the compressor
trying to start?
(Humming)
NO
YES
Have the steps been
followed in the
(Air Compressor will
not start) section?
See (Air Compressor
will not start) section?
Disconnect the air hose
from the air solenoid.
Turn the compressor on.
Dose the compressor start.
Replace the
air solenoid.
YES
YES
The compressor is ok.
NO
Is there air coming
out of the air
Pressure
Relief Valve?
YES
Repair or replace
Pressure
Relief Valve?
YES
Is there air coming
out of the air
solenoid exhaust?
Repair or replace
the air compressor.
Repair or replace
the air solenoid.
NO
NO
390 FinishPro
Air Compressor runs but will not build pressure.
Connect a test air gauge
to the air hose connector.
Start the compressor.
Do you have 32psi?
17

NO
See step 2. Do you have
over 100 AC volts?
YES
See step 1.Do you have
over 100 AC volts?
YES
Check the connector
for the white wires.
If ok repair or replace
the power Cord.
Replace the
power switch.
NO
See step 3.Do you have
over 100 AC volts? NO
YES
Replace the
power switch.
See step 5.
Do you have Continuity? NO Replace the
power switch.
FinishPro 395
ON/OFF Switch Test
Switch is good. Proceed to the proper Test Section
YES
Airless Motor will
not sart. See Control
Board Test Section
Compressor Motor will
not sart. See Compressor
will not start Test Section.
See pages 18 for the steps and illustrations.
See step 4 .Do you have
over 100 AC volts? NO
YES
Replace the
Control Board.
18

Compressor
Power
Cord
AA Mode
Airless Mode
Off
Step 4
Power switch in the AA Mode.
Blk meter led on the
Brown wire terminal.
Red meter led on Blue wire on
control boards N.
Cord plugged in.
Meter on AC Volts
110-120 AC
V
--
--
++
Blk
Green
Blk
Yellow
Blue
White
Blk
Brn
Grn/Yel
N
L
N
Compressor
Power
Cord
AA Mode
Airless Mode
Off
Step 5
Blk
Green
Blk
Yellow
Blue
White
Blk
Brn
Grn/Yel
N
L
N
Select
��
BEEP
++
-
Power Cord UNPLUGGED.
Power switch in the Airless Mode.
Meter set to continuity.
Yellow wires unplugged
from switch.
Meter should show
continuity or Beep.
FinishPro 395
ON/OFF Switch Test
Compressor
Power
Cord
AA Mode
Airless Mode
Off
Step 1
Power switch in
the Airless Mode.
Cord plugged in.
Meter on AC Volts
110-120 AC
V
--
--
++
Blk
Green
Blk
Yellow
Blue
White
Blk
Brn
Grn/Yel
N
L
N
Compressor
Power
Cord
AA Mode
Airless Mode
Off
Step 2
Power switch in
the Airless Mode.
Cord plugged in.
Meter on AC Volts
110-120 AC
V
--
--
++
Blk
Green
Blk
Yellow
Blue
White
Blk
Brn
Grn/Yel
N
L
N
Off
Compressor
Power
Cord
AA Mode
Airless Mode
Step 3
Power switch in the
AA Mode.
Blk meter led on the
Brown wire terminal.
Cord plugged in.
Meter on AC Volts
110-120 AC
V
--
--
++
Blk
Green
Blk
Yellow
Blue
White
Blk
Brn
Grn/Yel
N
L
N
19

Airless
OFF
Control Board
White
Blue
Brown
Black
Black
Power
Cord
Compressor
Control Board
White
Blue
Brown
Black
Black
Power
Cord
Compressor
Air-Assisted
Control Board
White
Blue
Brown
Black
Black
Power
Cord
Compressor
White
White
White
Brown
Brown
Brown
Blue
Blue
Blue
FinishPro™ 395 Switch Ladder Diagram
Airless Mode
Switch Down
Air Assisited Mode
Switch Up
Off
Switch Center
Yellow
Yellow
Yellow
Yellow
Yellow
Yellow