Systematics MP140 User manual

MP140 MIG COMBINATION UNIT
OWNER'S MANUAL
THE MP140
REPRESENTS THE LATEST TECHNOLOGY
IN MIG COMBINATION UNITS. THE MP140 OPERATES
ON 115 VOLT AC SINGLE PHASE CURRENT, AND FEATURES
"SMOOTH ARC" TRANSFORMER DESIGN CONCEPT.
FOR TECH. SERVICE, CALL 1-610-696-9040
INSTALLATION
OPERATION
MAINTENANCE
FORM WC5342 Rev. 8/00

MANUFACTURER’S LIMITED WARRANTY
This equipment is warranted against defects in materials
and workmanship for a period of two years from the date of
purchase.
EXCEPTION: THE MIG TORCH IS WARRANTED FOR A
PERIOD OF 30 DAYS FROM THE DATE OF PURCHASE.
Should the equipment become defective for such reason,
the Manufacturer will repair it without charge, if it is returned
to the Manufacturer’s factory, freight prepaid. This warranty
does not cover: (1) failure due to normal wear and tear; (2)
consumable parts, such as, but not limited to, torch contact
tips, gas cups and insulating bushings; (3) damage by
accident, force majeure, improper use, neglect, unauthor-
ized repair or alteration; (4) anyone other than the original
purchaser.
THIS LIMITED WARRANTY IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED. THE MANUFAC-
TURER SHALL NOT BE LIABLE FOR ANY INJURY TO
PERSONS, INCLUDING DEATH; OR LOSS OR DAMAGE
TO ANY PROPERTY, DIRECT OR CONSEQUENTIAL,
INCLUDING, BUT NOT LIMITED TO, LOSS OF USE,
ARISING OUT OF THE USE, OR THE INABILITY TO USE,
THE PRODUCT. THE USER ASSUMES ALL RISK AND
LIABILITY WHATSOEVER IN CONNECTION WITH THE
USE OF THE PRODUCT, AND BEFORE DOING SO,
SHALL DETERMINE ITS SUITABILITY FOR HIS IN-
TENDED USE, AND SHALL ASCERTAIN THE PROPER
METHOD OF USING IT.
SOME STATES DO NOT ALLOW LIMITATIONS ON
HOW LONG AN IMPLIED WARRANTY LASTS, OR THE
EXCLUSIONS OR LIMITATIONS OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES. SO THE ABOVE LIMITA-
TIONS OR EXCLUSIONS MAY NOT APPLY TO YOU. THIS
WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND
YOU MAY HAVE OTHER RIGHTS WHICH MAY VARY
FROM STATE TO STATE.
ARC WELDING CAN BE INJURIOUS TO OPERA-
TOR AND PERSONS IN THE WORK AREA -——
CONSULT INSTRUCTION MANUAL BEFORE
OPERATING.
ELECTRIC SHOCK can kill.
•Do not touch electrodes or other electrically live parts.
•Insulate yourself from work and ground.
•Install and ground machine in accordance with the National
Electical Code and local code(s). Read Operating Manual
before installing or operating.
•Do not operate with protective covers, panels, or guard
removed.
•Disconnect input power before servicing.
•Only qualified personnel should install, use, or service this
equipment.
ARC RAYS can injure your eyes and burn
skin.
•Wear correct eye, ear, and body protection while welding.
FUMES AND GASES can be dangerous to your
health.
•Use enough ventilation and/or exhaust at the arc.
•Keep your head out of fumes.
•Do not breathe fumes.
READ AND UNDERSTAND THE
MANUFACTURER’S INSTRUCTIONS AND
YOUR EMPLOYER’S SAFETY PRACTICES.
See American National Standard Z49.1, “Safety in
Welding and Cutting”, published by the American
Welding Society, 2501 N.W. 7th St., Miami, Florida
33125; OSHA Safety and Health Standards, 29 CFR
1910 available from U.S. Dept. of Labor, Wash.,
D.C. 20210.
!WARNING
Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
TABLE OF CONTENTS
ELECTRICAL SUPPLY REQUIREMENTS................................... 1
INTRODUCTION ........................................................................... 2
SPECIFICATIONS......................................................................... 3
CHECK LIST (CONTENTS) .......................................................... 4
INSTALLATION ............................................................................. 4
OPERATION ................................................................................. 7
MAINTENANCE ........................................................................... 13
TROUBLE SHOOTING CHART.................................................. 15
CONNECTING TIGIT2 OR MHG7 SPOOL GUN ........................ 20
CONSUMABLE PARTS BREAKDOWN ..................................... 22
PARTS BREAKDOWN - MIG TORCH ........................................ 23
OPTIONS - TIGIT2, MHG7 SPOOL GUN ................................... 24

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 1
ELECTRICAL SUPPLY REQUIREMENTS FOR THE MP140
Ensure that there is a 115 volt single phase, 20 amp electrical supply within easy reach
of the unit. The input cable supplied is 20 feet long. A 50 foot cable is an optional extra. The
plug which is factory installed is suitable for use up to 120 amps of output. The plug must
be changed if the welder is used above 120 amps of output. Attach a suitable plug making
sure the green wire is attached to ground. Refer to boxes below with the WARNING and
NOTE headings for more information. All wiring should be performed by a qualified
electrician.
WARNING
To conform to the National Electrical Code, the power input plug must be
changed if this unit is to be operated on a 20 amp circuit or higher.
Never change fuses or circuit breakers to a higher value than the wires and
outlet are designed for.
Breaker size - Wire size
15 Amp 14 Gauge
20 Amp 12 Gauge
30 Amp 10 Gauge
Do not rely on the circuit breaker built into the MP140 to protect your wiring.
This circuit breaker protects the MP140 internal wiring only.
Do not use undersized extension cords. Follow the cord manufacturer's
recommendations as to current carrying capacities.
Make sure all electrical wiring is installed by a qualified electrician.
NOTE
The maximum output of the MP140 will be limited by the size (amp rating) of
the circuit used.
Operation on a 15 amp circuit (14 gauge wire) will limit maximum
output to 100 amps.
Operation on a 20 amp circuit (12 gauge wire) will limit maximum
output to 120 amps.
Operation on a 30 amp circuit (10 gauge wire) will result in maximum
output of 140 amps.
MP140 output will be limited also by low input voltage (less than 120 volts),
long input cords and use of extension cords.

2Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
INTRODUCTION
The Systematics MP140 is a com-
bination welding power source,
wire feed unit, MIG torch and
accessory package. It operates on
115 volts AC input current and is
designed to meet the requirements
of auto body repair shops and light
fabrication. The MP140 produces
fusion welds by the Gas Metal Arc
Welding process (GMAW or MIG), on
steel up to 1/4" thick(aluminum 3/
16") , using .023" through .045"
steel wire and 3/64" aluminum
wire(Optional liners and contact
tips must be purchased to cover
given wire sizes). Heavier sec-
tions can be easily welded using
slightly different techniques. Con-
sumable MIG Spot/Stitch Welding on
steel can be performed with the
Optional SSTP-2 module installed.
The number of controls on the
unit have been reduced to assist
inexperienced operators learn MIG
welding. This facilitates rapid
set up for welding different thick-
nesses of material requiring vari-
ous heat inputs. The VOLTAGE con-
trol adjusts the welding voltage
and the WIRE SPEED control adjusts
the speed of the wire drive motor.
THE MIG PROCESS
AS APPLIED TO THE MP140
The MIG process uses a bare,
consumable electrode in the form of
spooled wire, which is fed by a
controllable speed feed unit through
the cable and torch to the weld. The
emerging wire and the weld are
shielded by a stream of CO2, Argon,
or a mixture of the two, which
prevents oxidation of the molten
weld puddle. The gas shield enables
high quality welds to be made
without the use of flux, eliminat-
ing the need for slag or flux
removal after the weld is com-
pleted.
The consumable electrode wire is
melted and transferred to the weld
puddle by the "short arc" or "dip"
transfer mode.
POWER SOURCE
WIRE SPOOL
FEED
ROLLS
WORK
MIG
TORCH
+
REVERSE
POLARITY
(STD.)
_
SHIELDING GAS
SHORT ARC OR DIP TRANSFER
Short arc transfer occurs at 12
to 22 arc volts (voltage while
welding), depending on wire size.
Welding commences as the arc is
struck and a weld pool is formed.
The tip of the electrode wire dips
into the pool and causes a short
circuit. The short circuit current
flow causes a rapid temperature
rise in the electrode wire and the
end of the wire is melted off. An
arc is immediately formed between
the tip of the wire and the weld
pool, maintaining the electrical
circuit and producing sufficient
heat to keep the weld pool fluid.
The electrode continues to feed and
again dips into the pool.
FIG. 1. SCHEMATIC OF MIG PROCESS
This sequence of events is re-
peated up to 200 times per second.
Short arc transfer is suitable for
positional welding. The heat input
to the workpiece is kept to a
minimum which limits distortion
and makes possible the welding of
thin sheet material.
FIGURE 2. SHORT ARC TRANSFER
ELEC-
TRODE
WORK

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 3
DESCRIPTION
The MP140 consists of a combina-
tion MIG welding power source and
wire feed unit, a MIG torch with 10
foot cable, a ten foot work (ground)
cable with ground clamp, a fifteen
foot power input cable, a gas
regulator/flowmeter, a torch ac-
cessory kit, and a built-in cylin-
der rack and industrial wheel kit.
Welder controls are simple and
clearly marked. The output voltage
is controlled by a six position tap
switch, providing six voltage se-
lections. Voltages can be moni-
tored by the voltmeter on the
control panel. Wire feed speed is
controlled by the wire speed poten-
tiometer.
An OPTIONAL SPOT/STITCH WELD
(SSTP-2)control module with ad-
justable timer circuit provides
Consumable MIG Spot Welding or
Stitch Welding capabilities of
light gauge steel.
SPECIFICATIONS
PART NUMBER: MP140
INPUT POWER REQUIREMENTS:
Voltage 115 volts AC
Phase single phase
Frequency 50/60 hertz
Current (see OUTPUT POWER)
OUTPUT POWER @ 100% Duty Cycle:
15 Amps Input Current = 100 Amps
20 Amps Input Current = 120 Amps
OUTPUT POWER @ 60% Duty Cycle:
30 Amps Input Current = 140 Amps
DUTY CYCLE TIME PERIOD:
10 minutes
OPEN CIRCUIT VOLTAGE:
18 - 33 volts DC
SPECIFICATIONS (Cont.)
ARC VOLTAGE: 14 - 24 volts DC
WELD CURRENT RANGE: 30 - 140 amps
WIRE TYPES: mild steel,
stainless steel, aluminum,
bronze, flux cored, flux cored
-
gasless
WIRE SIZES: .023" - .045" steel,
3/64" aluminum,
(.023" - 3/64" alum. w/ Spool Gun)
.030" - .035" bronze,
.030" - .045" flux cored
(gas shielded or gasless)
WIRE FEED SPEED RANGE:
50 - 500 inches per minute
SHIELDING GASES:
For Steel Argon/CO2 mix or CO2
For Aluminum, Bronze Argon
For Stainless Steel
Argon + 2% Oxygen
For Flux cored Argon/CO2 mix or
CO2
DIMENSIONS:
Height 31 in.
Width 14-1/2 in.
Depth 35-1/2 in.
Weight 175 lbs.
TORCH SPECIFICATIONS
NECK ANGLE: 60 degrees
LEAD LENGTH: 10 feet
OVERALL LENGTH: 10 feet
COOLING METHOD: gas (air)
RATING - 60% DUTY CYCLE:
With Argon/CO2 gas 200 amps
With CO2 gas 225 amps

4Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
CHECK LIST
THE SYSTEMATICS MP140 INCLUDES THE
FOLLOWING:
1- Combination Power Source/Wire
Feeder
1- Cylinder Rack/Industrial Wheel
Kit
1- 15TG10 MIG Torch with adjust-
able nozzle
1- 15 foot Power Input Cable with
Plug
1- 10 foot Work(Ground)Cable and
Clamp
1- MP250PK Parts Kit
1- GR-FM Gas Regulator/Flowmeter
1- Nozzle, 1/2 in. orifice (in-
stalled on MIG torch)
1- Contact Tip, for .030 in. wire
(installed on MIG torch)
1- ER70S-6-30-3, Sample Spool of
.030" Steel Wire
ITEMS REQUIRED FOR MIG WELDING
WHICH ARE NOT PROVIDED WITH THE
MP140
1. Full cover welding helmet with
proper colored lens (shade 9 to
11 depending on operator’s pref-
erence).
2. Proper shielding gas and cylin-
der.
3. Leather welding gloves.
4. 115 volt single phase AC power.
INSTALLATION
POSITIONING THE UNIT
Locate the unit near the welding
area and position it so there is
adequate clearance all around for
ventilation and maintenance.
ELECTRICAL SUPPLY
Follow the Electrical Supply
Requirements on page 1.
SHIELDING GAS CONNECTIONS
1. Place a cylinder of the appro-
priate shielding gas in the
rack at the rear of the machine
and secure it with the chain
provided.
2. Rapidly open and close the
cylinder valve. This will purge
dust and foreign matter from
the valve.
Take care to point the
valve outlet away from
yourself or other people,
as escaping high pressure
gas may be dangerous.
3. Attach the gas regulator/flow-
meter supplied with this unit,
to the cylinder valve using a
suitable wrench.
NOTE
If this unit is to be used
with 100% CO2 shielding
gas, an optional gas regu-
lator coupler is re-
quired.
CAUTION
FIG. 3. GAS FLOW ADJUSTMENT
GAUGE -
INDICATES
TANK
PRESSURE
OUTLET
FITTING
TO
WELDING
MACHINE
GAS FLOW
ADJUSTING
KNOB
INLET
FITTING
TO
TANK
FLOW TUBE
INDICATES
FLOW RATE
IN C.F.H.

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 5
FITTING AND THREADING THE ELEC-
TRODE WIRE - ALWAYS USE ER70S-6
WELDING WIRE
1. Remove the wire spool clip from
the spool hub.
2. Unpack the spool of welding
wire from its protective pack-
aging.
3. Place the spool of ER70S-6
welding wire onto the hub. The
wire is fed off the bottom of
the spool.
Look for and remove any
wire protruding from the
center of the spool. The
protruding wire is elec-
trically
HOT during weld-
ing and must not touch
the machine.
4. Replace the spool clip on the
hub.
5. Unlatch the pressure roll arm
and swing it open.
6. Make sure the double v-groove
drive roll is installed to
match the wire size. To change
the wire size setting, remove
the drive roll, turn it over and
reinstall it on the shaft.
(continued on following page)
SHIELDING GAS CONNECTIONS(Cont.)
4. Fit the gas hose from the
welding machine to the regula-
tor outlet fitting and tighten
it with a suitable wrench. Open
the cylinder valve.
5. Check that the gas regulator is
properly adjusted. When weld-
ing steel, the gas flow rate is
30 CFH. When welding aluminum,
the gas flow rate is 40 CFH.
NOTE
The MP140 must be turned
"ON" and the MIG torch
trigger depressed, before
the gas flow rate can be
adjusted.
TORCH CONNECTION
1. Open the access door of the
machine to its fullest extent.
2. Back out the thumb screw lo-
cated on the drive assembly
mounting bracket inside the
machine. Insert the MIG torch
into the torch panel mount on
the front panel and TIGHTEN THE
THUMB SCREW.
CAUTION
FIG. 5. DOUBLE GROOVE DRIVE ROLL
"A" SIDE FACING IN FOR
.023" - .035" STEEL WIRES
"B" SIDE FACING IN FOR
.040" - .045" STEEL WIRES
AND 3/64" ALUMINUM WIRES
TORCH PRESSURE
PANEL ROLL
MOUNT
MIG
TORCH
THUMB
SCREW
DRIVE DRIVE
ROLL ASSEMBLY
FIGURE 4. TORCH CONNECTION

6Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
FITTING AND THREADING THE ELEC-
TRODE WIRE (Continued)
12.Install the contact tip over the
protruding wire and tighten it
firmly using a proper size
wrench. Make sure the tip is the
correct size for the wire being
used.
13.Install the nozzle on the torch.
For steel, the contact tip
should be flush or stick out up
to 1/16 inch beyond the end of
the nozzle. For aluminum, the
contact tip should be recessed
1/8 to 1/4 inch inside the
nozzle. Using wire cutters,
trim off the wire so the stickout
is approximately 1/4 inch for
steel or 1 inch for aluminum.
For aluminum, the end of the
wire should be bent over so it
does not JAM into the work. This
is called a "scratch start".
FITTING AND THREADING THE ELEC-
TRODE WIRE (Continued)
7. Release the wire from the spool
and trim off the kinked end with
wire cutters. The wire must be
straight when it enters the
inlet guide.
8. Thread the electrode wire through
the inlet guide, over the feed
roll and into the torch liner.
Ensure that the wire locates in
the feed roll groove. Do not
allow the wire on the spool to
loosen.
9. Close and relatch the pressure
roll arm.
10.Stretch the torch cable straight
out in front of the machine
making sure there are no kinks.
Remove the nozzle and contact
tip from the torch.
11.Turn "ON" the circuit breaker on
the front of the machine. The
cooling fan will start and the
"ON" indicator light will illu-
minate. Set the VOLTAGE control
switch to "4", the function
switch to "CONTINUOUS WELD" (if
the unit has the optional SSTP-
2 installed) and the WIRE SPEED
control to "7". Pull the
trigger on the MIG torch. The
wire feed system will start and
wire will be fed through the
cable liner and torch. If the
wire does not feed, or appears
to slip, tighten the pressure
roll arm adjusting nut. Feed
the wire until it protrudes
from the front of the torch
approximately six inches.
Keep hands and face away
from the front of the
torch and do not allow the
wire to contact ground.
The wire is electrically
HOT when the torch trigger
is actuated.
1"
STICK-OUT
1/4"
STICK-
OUT
FOR ALUMINUM:
CONTACT TIP
RECESSED 1/8" - 3/8"
FOR STEEL:
CONTACT TIP
FLUSH WITH NOZZLE
14.For steel welding only, spray
anti-spatter compound inside
the nozzle and on the outside of
the contact tip. For aluminum
or stainless steel welding, NO
anti-spatter compound can be
used as it will contaminate the
weld.
FIGURE 6.
WIRE STICKOUT - STEEL, ALUMINUM
CAUTION

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 7
WIRE FEED PRESSURE ROLL ADJUSTMENT
The wire feed pressure roll is
adjusted to the proper setting at
the factory, prior to delivery. It
may be necessary to readjust the
setting as components "seat in" or
when changing to a different diame-
ter wire. To check for proper roll
pressure, hold the torch in one
hand and the wire between two
fingers of the other hand. Pull the
torch trigger. If the wire contin-
ues to feed when firm pressure is
applied to the wire, the pressure
roll adjusting nut should be backed
off until the feed rolls start to
slip. If the wire will not feed
with very little pressure applied,
the pressure roll adjusting nut
should be tightened.
OPERATION
The following operating instruc-
tions and detailed setup proce-
dures enable an operator without
previous experience to produce
quality fusion welds. It is recom-
mended that an operator without
prior experience with this equip-
ment, first practice on scrap metal
of the same type and thickness as
the material to be welded.
OPERATING SEQUENCE
1. Make sure that the pieces of
metal to be welded are free of
grease, dirt, paint and scale.
Use a wire brush to remove paint
and scale. Paint must be com-
pletely removed to bare metal.
Grease and oil could burn and
cause a fire or safety hazard.
Failure to clean the metal
properly will result in erratic
and porous welds.
2. Install the unit as directed in
the installation instructions
and make sure the work clamp is
firmly attached to a cleaned
area on the workpiece to be
welded.
3. Open the shielding gas cylinder
valve. Press the torch trigger
and listen for gas flow. Adjust
the gas flow rate to 30 CFH for
steel and 40 CFH for aluminum.
The welding wire will feed
when the trigger is actu-
ated. Take care that the
wire is not directed to
hit yourself or anything
that is grounded to the
ground wire on the welder.
CAUTION
PRESSURE ROLL
ADJUSTING NUT
PRESSURE
ROLL
PRESSURE
ROLL ARM
DRIVE
ROLL
TORCH SELECTOR CABLE
Plug the torch selector cable
into the Positive (+) terminal on
the machine(see "Process Selec-
tion" on page 8 for further de-
tails).
WORK (GROUND) CABLE
Uncoil the work cable and plug it
into the negative (-) terminal on
the machine.
FIGURE 7.
PRESSURE ROLL ADJUSTMENT

8Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
PROCESS SELECTION
The following controls are lo-
cated on the front of the machine.
D. "ON" INDICATOR LIGHT
Illuminates when the circuit
breaker on the machine is "ON".
E. TORCH PANEL MOUNT
Combination power output, con-
tactor switch connection, gas
supply connection, and wire
feed output in a single unit.
F. TORCH SELECTOR CABLE
Plugs into (+) positive termi-
nal for standard welding opera-
tion or (-) negative terminal
for straight polarity welding
on very light sheet metal or for
using flux cored gasless wire.
G. VOLTMETER
Indicates open circuit voltage
when torch switch is actuated
or arc voltage when welding.
H. +(POSITIVE) TERMINAL
Positive output terminal from
the welder DC power source. The
torch selector cable is plugged
into this terminal for standard
welding operation. The work
cable can be plugged into this
terminal for straight polarity
welding on very light sheet
metal or for using flux cored
gasless wire.
I. -(NEGATIVE) TERMINAL
Negative output terminal. The
work cable is plugged into this
terminal during standard weld-
ing operation. The torch se-
lector cable can be plugged
into this terminal for straight
polarity welding on very light
sheet metal or for using flux
cored gasless wire.
A. VOLTAGE CONTROL
Six position switch adjusts
welder output voltage.
B. WIRE SPEED
Potentiometer controls speed
of wire drive motor to give wire
speed of 50 to 500 inches per
minute.
C. CIRCUIT BREAKER
Primary power switch and over-
load protection device.
FIGURE 8. FRONT PANEL
A.
VOLTAGE
CONTROL
B.
WIRE
SPEED
C.
CIRCUIT
BREAKER
D
"ON"
INDICATOR
LIGHT
E.
TORCH
PANEL
MOUNT
F.
TORCH
SELECTOR
CABLE
G.
VOLTMETER
H.
(+)POSITIVE
TERMINAL
I.
(-)NEGATIVE
TERMINAL

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 9
PROCESS SELECTION (Cont.)
The following controls are lo-
cated on the inside of the machine,
in the wire feed compartment.
E. *FUNCTION SWITCH
Controls mode of operation of
welding machine. "CONT. WELD"
position is for normal, con-
tinuous welding operation.
"SPOT" position puts the spot
timer in the circuit for auto-
matic MIG Consumable Spot Weld-
ing. "STITCH" position is used
for stitch welding on very
light material. When in
"STITCH" position, the length
of time the welder is "ON" and
feeding wire is controlled by
the Spot Timer. The lower the
Spot Timer setting, the faster
the welder cycles on and off.
A.
*OPTIONAL
SSTP-2
MODULE
B.
*SPOT
TIMER
C.
SELECTOR
HOSE
D.
PARAMETER
CHART
E.
*FUNCTION
SWITCH
WELDING
Optimum control settings will
vary according to the thickness of
the metal, the type of joint,
operator preference, etc. Best
results can be obtained through
experience with the welding ma-
chine or by making trial welds.
Select some sample material of the
same type and thickness as the
material to be welded. Refer to the
Parameter Chart located on the
access door to the wire feed
compartment. Set the welding
controls for optimum results using
the sample material thickness and
wire size being used as a starting
point, weld until experience is
gained using the unit.
CONTINUOUS WELDING ON STEEL
1. Trim the electrode wire to
leave approximately 1/4 inch
stickout beyond the end of the
contact tip and install the
welding nozzle. The contact tip
should be flush or stick out up
to 1/16 inch beyond the end of
the nozzle.
A. *OPTIONAL SSTP-2 MODULE
With the optional Spot/Stitch
Module installed MIG Spot weld-
ing and Stitch welding can be
performed.
B. *SPOT/STITCH TIMER
After the torch trigger is
actuated, the timer allows the
wire to feed and the gas and
power to flow for the time
selected. The Function Switch
must be set in the "SPOT"
position (or the "STITCH" posi-
tion for stitch welding).
C. SELECTOR HOSE
Attaches to MIG position for
Standard welding through the
MIG torch assembly or to MHG7
position for Aluminum welding
with the spool gun option.
D. PARAMETER CHART
This chart is a guide for basic
setup parameters.
(continued on following page)
FIGURE 9. WIRE FEED COMPARTMENT

10 Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
CONTINUOUS WELDING ON STEEL
(Cont.)
FIGURE 10. NOZZLE ADJUSTMENT
FOR WELDING STEEL
CONTACT TIP
(FLUSH TO
1/16" STICKOUT)
ELECTRODE WIRE
(1/4" STICKOUT)
NOZZLE
2. Spray the inside of the nozzle
and the outside of the contact
tip with anti-spatter spray.
3. Locate the torch over the joint
to be welded with the contact
tip approximately 3/8 inch from
the work surface.
NOTE
When welding steel, the ideal
position for holding the torch
is inclined approximately 30
degrees towards the direction
of travel. This allows the arc
to be seen easily, resulting
in greater control of the weld
pool. Most right-handed wel-
dors move from left to right.
This method, known as fore-
hand welding, provides a gas
shield for the cooling weld
puddle and helps in obtaining
an oxidation free weld de-
posit.
4. Use a welding helmet with a
shade 9 to 11 filter lens,
depending on operator prefer-
ence.
5. Squeeze the torch trigger. The
wire will feed and an arc will
be established. As the weld is
deposited, move the torch slowly
along the weld seam at a con-
stant speed, maintaining a con-
stant arc length and a constant
tip-to-work distance.
FIGURE 11. TORCH POSITION
FOR WELDING STEEL
- RIGHTHANDED WELDOR
30 DEGREES
DIRECTION
OF TRAVEL
SHIELDING
GAS
WORK

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 11
CONTINUOUS WELDING
ON ALUMINUM
(Optional Nylon liner and 100%
Argon shielding gas are
required)
1. Trim the electrode wire, leav-
ing approximately 1 inch stick-
out beyond the end of the
nozzle. Bend the wire over as
shown, to allow for a scratch
start. The contact tip should
be recessed inside the nozzle
approximately 3/8 inch. This
helps prevent the welding wire
from burning back to the con-
tact tip.
DIRECTION
OF TRAVEL
WORK
10 DEGREES
SHIELDING GAS
NOZZLE
CONTACT TIP
(RECESSED 3/8")
ELECTRODE
WIRE
(1" STICKOUT)
2. DO NOT spray any anti-spatter
material on the torch or base
metal and DO NOT attempt to
lubricate the aluminum wire in
any way. Weld contamination
will occur unless the wire,
base metal, torch and work area
are kept clean.
3. Bring the torch nozzle to 1/2 to
5/8 inch from the workpiece.
The recommended position of the
torch and direction of travel
for welding aluminum are shown
in figure 13.
4. Follow steps 4 and 5 as in
"Continuous Welding on Steel".
FIGURE 12.
NOZZLE ADJUSTMENT
FOR WELDING ALUMINUM
MIG SPOT WELDING ON STEEL
(OPTIONAL)
NOTE
MIG Spot Welding is NOT
recommended for aluminum.
1. Trim the electrode wire so the
stickout from the contact tip
will be flush with the nozzle
face, and fit the spot nozzle in
place.
2. Set the VOLTAGE control to "6",
the WIRE SPEED control to "9",
the Function Switch to "SPOT",
and the TIME control to "2",
then adjust the various con-
trols to obtain a perfect weld.
Refer to the Parameter Chart,
located on the access door to
the wire feed compartment, for
basic setup recommendations.
(continued on following page)
FIGURE 13. TORCH POSITION
FOR WELDING ALUMINUM

12 Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
MIG SPOT WELDING ON STEEL
(Continued)
3. Locate the torch on the area to
be welded and press the nozzle
firmly against the work to hold
the metals in place.
4. Guard the eyes against stray
arc flash. A weldor’s helmet is
not necessary when spot weld-
ing. However, extreme caution
must be taken to avoid looking
at the arc.
5. Actuate the torch trigger to
start the weld sequence. When
the timer switches off the weld
current, release the trigger
but maintain firm contact be-
tween the torch and work. Wait
one second for the weld puddle
to solidify, then move to the
next spot position. If the wire
freezes in the puddle, a quick
squeeze of the torch trigger
will melt it off.
6. To ascertain a good spot weld,
look at the back side of the
welded material. A small melt-
through of approximately 1/16
inch diameter is ideal.
STITCH WELDING ON STEEL
(OPTIONAL)
NOTE
Stitch Welding is used for
very light material.
1. Set Function Switch to "STITCH".
2. Adjust the TIME control to set
the time the welder is "on" and
feeding wire. The lower the
setting, the shorter the "on"
time and the faster the unit
cycles on and off.
3. Weld using "Continuous Weld-
ing" torch position and direc-
tion of travel.
DIRECTION
OF TRAVEL
WORK
SHIELDING GAS
30 DEGREES
FIGURE 15. STITCH WELDING
WORK
SPOTWELD
SPOTWELD
NOZZLE
CONTACT
TIP
PRESS NOZZLE
FIRMLY
AGAINST WORK
FIGURE 14. MIG SPOT WELDING

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 13
OPERATING HINTS
BURN BACK
In the event the welding wire
burns back into the contact tip:
1. Remove the nozzle from the
torch.
2. Unscrew the contact tip from
the gas diffuser using a pair of
pliers as the tip will be very
hot.
3. Free the wire from the contact
tip and clean the end of the tip
so the new wire will slide
smoothly through the hole. DO
NOT use a drill or reamer to
clean the hole as that will
enlarge it and cause an erratic
arc. Replace the contact tip if
it is badly damaged.
4. Install the contact tip in the
torch and tighten it firmly
with an appropriate wrench.
5. Reinstall the torch nozzle.
6. If the wire continues to burn
back, check for erratic wire
feed, or speed up the wire by
increasing the WIRE SPEED con-
trol setting or reducing the
VOLTAGE control setting.
SPATTER
Before beginning to weld and
periodically during welding, the
torch nozzle must be removed and
the spatter (small globules of
melted metal) cleared from the
inside of the nozzle and the
outside of the contact tip and the
gas diffuser. Spatter buildup be-
tween the contact tip and the
nozzle can cause a short circuit
and consequently, failure of the
torch or welding machine. The
frequent use of anti-spatter spray
will help prevent the adherence of
spatter to the torch components.
NOTE
DO NOT use any anti-spat-
ter spray when welding
aluminum or stainless
steel.
Restricted gas flow, holding the
torch too far from the work piece,
and the use of CO2 gas rather than
75% Argon - 25% CO2 will increase
the spatter levels.
MAINTENANCE
To ensure that this equipment
maintains its operating efficiency,
the following maintenance schedule
and procedures are recommended.
These routines should be performed
regularly by the operator.
REGULARLY - Usage and shop condi-
tions determine frequency.
1. Remove and clean the torch
nozzle and contact tip. The use
of anti-spatter spray will re-
duce the adherence of spatter
and makes its removal easier.
2. Blow out the torch liner prior
to the installation of each new
spool of wire. The contact tip
and gas diffuser must be re-
moved, but it is not necessary
to remove the liner.
3. If the torch cable assembly is
bent severely, a kink may de-
velop in the steel liner. This
can cause wire feeding problems
so a new liner should be in-
stalled.
(continued on following page)

14 Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
In the event of the failure of any
part of this equipment, contact
your Systematics representative
for replacement parts and service.
DO NOT lift the unit when a gas
cylinder is installed or at-
tached.
DO NOT weld on any item that
has a common electrical ground.
DO NOT operate the unit with
the side panels removed. Over-
heating will occur.
DO NOT weld upon the case of
the welding machine.
ONLY a qualified electrician
should perform work inside
the welding machine.
ALWAYS wear protective cloth-
ing, leather gloves and a full
cover welding hood while weld-
ing.
DO NOT weld in a closed in
area. Proper ventilation is
a necessity, or a fresh air
supplied hood should be worn.
WHEN welding near com-
bustibles, a helper or
"watcher" should stand by
with a fire extinguisher or
other fire protective device.
NEVER weld on a closed vessel
or one that has contained
combustibles.
IF IN DOUBT - DON’T DO IT!
BE SAFE - DON’T BE SORRY!
MAINTENANCE (Cont.)
WEEKLY
1. Remove dirt and dust from the
wire feed compartment. Use low
pressure dry compressed air.
2. Remove dirt and metal deposits
from the grooves in the feed
roll. If the grooves are badly
worn, the feed roll should be
replaced. If the pressure roll
does not turn freely, it should
be replaced.
3. Check all gas fittings for
leaks. Tighten or repair as
required.
EVERY SIX MONTHS
1. Disconnect the welder from its
main power supply.
2. Remove the machine’s side pan-
els.
3. Using low pressure dry com-
pressed air, remove dust and
dirt from all components.
4. Check for loose or frayed wir-
ing. Particularly check weld-
ing current wire connections.
5. Replace the torch liner if
necessary.
RECOMMENDED
CUSTOMER SPARE PARTS
The Systematics MP140 is a ma-
chine of proven design and relia-
bility. Following is a list of
consumable items recommended as
spare parts for this unit.
contact tips...... M3-T30, etc.
gas nozzles............ M3T-N50
nozzle insulators ........M3T-B
gas diffusers ............M3T-D
steel liner(.020-.030) M103L-B
steel liner(.035-.045) M104L-N
WARNING

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 15
TROUBLE SHOOTING (SYMBOL*)
FOR TECH. SERVICE, CALL 1-610-696-9040
The Trouble Shooting Chart is a guide in identifying and correcting
possible troubles which may occur when operating this equipment.
FAULT POSSIBLE CAUSE REMEDY
(SYMBOL*) - USE THIS IDENTIFIER, ALONG WITH THE SCHEMATIC DIAGRAM FOUND IN THE SERVICE
MANUAL, FOR TROUBLE-SHOOTING PURPOSES.
EQUIPMENT MALFUNCTION
No main power, MP140 switch is "OFF".
(CB1) Turn switch "on".
fan does not Wall breaker is "tripped". Reset wall breaker.
operate, "Open" circuit breaker Reset or replace
"on" indicator on MP140. (CB1) breaker.
light is off. Loose or broken connection Tighten or repair
in power input circuit. connection.
Main power on, MIG torch unplugged. Plug in MIG torch.
torch Faulty trigger switch. (S1) Replace micro switch.
trigger Fault in torch cable. Check torch cable
activated, for continuity.
no response. Loose or broken connection Check or repair
on wiring harness. connections.
Wire feed motor unplugged. Plug in motor.
(RC1)
Faulty control transformer. Check for 28VAC output.
(T2)
Loose spot timer (MP140S) Install properly.
circuit board. (PC2)
Defective spot timer (MP140S) Replace board.
circuit board. (CR2)(PC2)
Main power on, Pressure roll arm unlatched. Latch arm & add tension.
torch "Slippage" at drive rolls. Increase drive roll
trigger tension. See page 7.
activated, Wire path restricted. Clean path or replace
no wire feed torch liner.
but contactor 5 amp mini breaker is Reset or replace
operates & tripped. (CB2) breaker.
gas flows. Wire feed circuit board Calibrate wire feed
needs calibrated. circuit board. See
page 19.
Defective wire feed Replace circuit board.
circuit board. (PC1)
Faulty wire feed motor Repair or replace
or connection. (M) faulty item.
Check motor on a
12VDC battery.
Faulty motor relay. (CR1) Sand points or replace
relay.
Loose or broken connection. Tighten or repair
connection.

16 Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
FAULT POSSIBLE CAUSE REMEDY
TROUBLE SHOOTING (Cont.) (SYMBOL*)
FOR TECH. SERVICE, CALL 1-610-696-9040
(continued on following page)
EQUIPMENT MALFUNCTION (Cont.)
Main power on, Loose torch thumb screw. Tighten thumb screw.
torch Broken or loose connection. Check cables for
trigger continuity.
activated, Repair or tighten
no welding connections.
current, but Unplugged or faulty power Plug in or replace
gas flows & contactor switch. (W) switch.
wire feeds. #1 Transformer wire off. (W) Reattach wire.
"Opened" thermal switch. Allow unit to cool, then
(TP1) retry.
Faulty diodes. (D1-D2) Check diodes. See page
18.
Torch No shielding gas Replace tank.
trigger - tank empty.
activated, Loose or broken Tighten or repair
no gas flow, connections. connections.
but contactor Faulty Gas solenoid Repair or replace
operates & valve. (GS) valve.
wire feeds. Clogged gas flow path. Locate & clean clog.
Loose spot timer (MP140S) Install properly.
circuit board. (PC2)
Defective spot timer (MP140S) Replace board.
circuit board. (CR2)(PC2)
FAULTY WELDS
"Jerky" or Worn , kinked or dirty torch Clean or replace
"slipping" liner. liner.
wire feed. Wire spool turns too Lub spool shaft. Read-
just hard. spool drag.
Worn double v-groove drive Replace drive roll.
roll.
Weak pressure roll spring. Replace spring.
Worn or dirty contact tip. Replace contact tip.
Worn inlet guide(s). Clean or replace guides.
Sticking pressure roll. Replace pressure roll.
Feed roll tension incorrect. Adjust feed roll ten-
sion. See page 7.

Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380 17
TROUBLE SHOOTING (Cont.) (SYMBOL*)
FOR TECH. SERVICE, CALL 1-610-696-9040
FAULT POSSIBLE CAUSE REMEDY
FAULTY WELDS (Cont.)
"Birdnesting" Excessive feed roll tension. Reduce tension. See page
(Wire wrapping 7.
around drive Poor alignment. Make sure wire is
rolls) properly aligned
across roller.
Oversize contact tip. Replace contact tip with
correct size.
"Cold" weld Incorrect machine settings. Increase heat & wire
puddle. speed.
Incorrect shielding gas. Replace with proper gas.
Excessive wire stick-out. Hold torch closer to
work.
Poor connections. Check and tighten all
connections.
Faulty diode. Test diodes, replace
(D1-D2) faulty diode(s). See
page 18.
Heavy spatter. Incorrect machine settings. Increase heat, decrease
wire feed speed.
Incorrect shielding gas. Replace with proper gas.
Excessive wire stick-out. Hold torch closer to
work.
Porous welds. No shielding gas. Turn on gas.
Not enough gas flow. Check hoses for leaks,
make sure cylinder is
not empty. Increase
flow rate.
Contaminated wire. Change wire.
Faulty gas solenoid. Replace solenoid.
(GS)
Incorrect electrode wire. Use correct wire.
Contaminated base material. Clean or etch base
material.
(SYMBOL*) - USE THIS IDENTIFIER, ALONG WITH THE SCHEMATIC DIAGRAM FOUND IN THE SERVICE
MANUAL, FOR TROUBLE-SHOOTING PURPOSES.

18 Systematics , Inc. 1025 Saunders Lane West Chester, PA. 19380
TESTING AND REPLACING
DIODES
Silicon diodes have proven to be
highly reliable. However, weld
spatter build-up in the torch can
short out and cause diode overload
and consequent failure. The fol-
lowing information is provided as
a guide should a failure be sus-
pected.
Silicon diodes exhibit two main
fault conditions:
1. "Open Circuit" - causes a re-
duction in welder output.
2. "Short Circuit" - causes the
circuit breaker to trip.
If a fault is suspected, the
diode may be tested as follows:
1. Remove the top connection of
each diode to be tested.
2. Using a Volt-Ohm Meter set on
RX1K, check for continuity
through the diode in both di-
rections. If there is no
continuity in either direc-
tion, the diode is in "open
circuit" condition and must be
replaced. If there is continu-
ity in both directions, the
diode is in "short circuit"
condition and must be replaced.
If there is continuity in one
direction only, the diode is
functioning properly.
CAUTION
+-
+-
12 VOLT
LIGHT BULB
DIODE 12 VOLT
BATTERY
12 VOLT
LIGHT BULB
DIODE 12 VOLT
BATTERY
3. If all the diodes check out
satisfactorily with the Volt-
Ohm Meter, a load check must be
made. This is easily accom-
plished using a twelve volt
battery and a twelve volt light
bulb connected as shown. Again
test for electrical current
flow in both directions. The
bulb should light in one (1)
direction only - not both.
NEVER use a "megger" or a
high voltage device to
test a diode.
4. When replacing diodes, it is
very important that a heat
conductive compound (Radio Shack
#276-1372) be used where the
diode makes contact with the
aluminum heat sink. Do not
grease the threads on the di-
ode.
FIGURE 16. DIODE LOAD CHECK
CONNECTION DIAGRAM
- TEST FOR FLOW IN BOTH DIRECTIONS