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
--
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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
--
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Black
Red
Yel
Yel
Known Value
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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