Midway Off Road Thunder Operation Manual

							Servicing          5-5 • 
Dollar Bill Validator
 (Use MARS AE2451-U3E, UL-recognized currency changer)
  You can install dollar bill validators in VGMs manufactured with the additional wiring connector. As
this manual goes to press, this VGM only supports the Mars model AE2451-U3E validator.
 
  Switch off power to the VGM and unplug the AC line cord. Unlock the coin door and swing it open.
Read the coin door label for additional information.
 
  Remove nuts, spacers, and the cover plate from the door. Before mounting the validator, change
switch settings or make adjustments. (Set the validator for 1 pulse per dollar. Also adjust the pulse
width setting. The validator must generate pulses with these timing parameters: 50mS on and 50mS
off.) If the manufacturer supplied an adapter plate, place it over the door cutout. Install spacers on
threaded studs. Then align the validator mounting holes with the studs. Seat the validator in the door
opening. Install the nuts and tighten them.
 
  Attach the ground wire (green with yellow stripe) lug to the door ground stud. The stud is beside the
hinge. Mate the wiring harnesses and press them together to fully seat connectors. Route wires away
from the door edges and hinge. To remove a validator for service or replacement, reverse these
steps.
 
Plug in the line cord and turn on the VGM. From the Menu System, change the mechanism setup and
pricing. Then test known good and bad bills to verify proper operation. Close and lock the coin door.
• 
Fans
 
The Arcade Computer incorporates several fans. Two fans reside at the bottom of the Arcade
Computer enclosure. The power supply includes one fan. Inside the microprocessor cartridge is
another small fan.
 
 
 
  Switch off power to the
VGM. Remove the cabinet
rear door. Remove the back
of the Arcade Computer.
 
  FANS AT THE BOTTOM OF
THE ENCLOSURE.
Disconnect the fan’s power
harness. Remove the fan
mounting screws. Note the
fan orientation. Each fan has
an arrow molded into its
plastic case to indicate
airflow direction. Slide the
fan out of its mounting
bracket. Be certain to
reinstall the fan in the proper
direction to assure airflow
over circuitry.
  POWER SUPPLY FAN. 
The power supply contains no user-serviceable parts. Never open the power
supply. 
						

							Servicing          5-6 MICROPROCESSOR FAN. 
Dis-
connect the DC power cable from
the floppy drive. Unplug the
ribbon cable from the floppy
drive. Leave the other end of the
cable attached to the CPU Board.
Unscrew and remove the circuit
board retention bars. Remove the
drive bracket mounting hardware.
Remove the bracket and drive.
Disconnect the fan’s power
harness. Remove the
microprocessor cartridge.
Squeeze the plastic end tabs on
the fan side of the cartridge.
While squeezing, carefully pry the
fan assembly away from the
heatsink. If the fan is bad, replace
the entire fan assembly with a
new one. Reassemble the
cartridge and insert it into the
computer. Then reconnect fan
power.
• Floppy Disk Drive
Switch off power to the VGM. Unlock and remove the rear door. Remove the back of the Arcade
Computer. Disconnect the DC power cable from the floppy drive. Unplug the ribbon cable from the
floppy drive. Leave the other end of the cable attached to the CPU Board. Unscrew and remove the
circuit board retention bars. Remove the drive bracket mounting hardware. Remove the bracket.
Remove the drive mounting screws. Lift the drive off the mounting bracket. Save the mounting screws
for reuse in future floppy drive installations. When returning a floppy drive to your distributor, pack it in
an anti-static bag.
REINSTALLATION. 
Mount the floppy drive in its bracket. Install the drive mounting screws. Reinstall
the bracket and drive in the Arcade Computer enclosure. Connect the drive’s ribbon and power
cables.
• 
Gas and Brake Pedals
Switch off power to the VGM. Adjust the
seat to the maximum rear position.
Remove four outer mounting screws
from the front edges of the pedal plate.
Gently pull the pedal mechanism toward
the seat until the mechanism clears the
cabinet opening. Disconnect the pedal
cable from the wiring harness.
Disconnect the green / yellow safety
ground wire. Lift the pedal mechanism
up and away from the cabinet. 
						

							Servicing          5-7 • 
Gear Shift
Switch off power to the VGM. Unlock and remove the rear door. Disconnect the two cables from the
back of the shifter. At the front of the shifter, remove shift plate mounting screws. Lift the shifter up
and out of the player panel.
• 
Hard Disk Drive
CAUTION: 
Hard disk drives are very fragile! Handle them with care. Keep disk
drives away from magnets, heat and vibration. Don’t move a VGM with the power
on.
CAUTION: 
Don’t stack or drop hard disk drives. Use an anti-static bag and an
approved shipping container to return the drive to your distributor.
CAUTION:
 Static electricity builds up on your body. This static can damage or
destroy sensitive circuits. Before touching or handling electronics, discharge static
electricity by touching the power supply chassis.
Switch off power to the VGM. Unlock and remove the rear door. Remove the back of the Arcade
Computer. Disconnect the DC power cable from the hard drive. Unplug the ribbon cable from the hard
drive. Leave the other end of the cable attached to the CPU Board. Remove the drive mounting
screws. (Don’t remove the drive-mounting bracket.) Lift the drive out of the cabinet. Save the
mounting screws for reuse in future hard drive installations. When returning a hard drive to your
distributor, pack it in an anti-static bag. Box the drive in approved shipping container 08-8068.
REINSTALLATION. 
Before mounting the hard drive in its bracket, install the drive mounting screws.
To avoid damage during installation, mount the hard drive in the brackets before connecting cables.
After a driver plays one game, the new drive copies data from other linked VGMs. Important! The
data won’t copy if players are actively driving. Files transfer only when all VGMs return to Attract
Mode.
• 
MagicBus

  Interface Board
Switch off power to the VGM. Unlock and open the rear door. Extract the harnesses from the board
connectors. The MagicBus Board mounts to the left cabinet wall. Remove mounting screws from the
board. Lift the board out of the cabinet. During reinstallation, tighten the screws: Start at the board’s
center and work toward the outer edge. If you aren’t reinstalling the board, store it in an anti-static bag
and protective container.
• 
Marquee Glass and Fluorescent Tube
Switch off power to the VGM. Unscrew and remove the marquee glass retainer. Lift off the glass
panel and artwork to expose the interior of the light box. The fluorescent lamp requires a quarter turn
for removal. 
						

							Servicing          5-8 • 
Microprocessor
This VGM’s microprocessor is in a postcard-size cartridge that also includes cache RAM. The
cartridge is inside the Arcade Computer, near the DIMM sockets. Switch off power to the VGM.
Remove the cabinet rear door. Remove the back of the Arcade Computer. Unplug the ribbon cable
from the floppy drive. Leave the other end of the cable attached to the CPU Board. Unscrew and
remove the circuit board retention bars. Remove the floppy drive mounting bracket. Remove the
floppy drive. Disconnect the microprocessor fan power harness. Spread the locking retainers on each
side of the microprocessor cartridge. Pull the cartridge out of its socket. Take care not to touch the
copper traces on the socket.
To reinstall a microprocessor cartridge, orient the cartridge over its socket. Make sure that you’ve
positioned the keying notch properly. Push the microprocessor cartridge into its socket, so that the
cartridge snaps into place under the locking retainer on each side of the socket. Be sure that the
retainers mate tightly with cartridge notches. Don’t attempt to force a cartridge into its socket.
Reconnect the microprocessor fan harness.
• 
Monitor
CAUTION: 
The video monitor is heavy, with most of the weight toward the front of
the assembly. Support the monitor as you remove it from the cabinet.
WARNING:
 The monitor doesn’t require isolation from AC line voltage during
normal VGM operation. W hen operating the monitor outside the cabinet, use an
isolation transformer. Connect the transformer between the monitor and line.
 
Switch off power to the VGM. Unlock and remove the rear door. From inside the cabinet, disconnect
the dash cables. Remove the top two dashboard mounting screws. Remove the dash bracket. Slide
the viewing glass upward. Lift the glass out of the cabinet. Disconnect cables from the speedometer
and tachometer. Remove the dashboard. Remove the monitor bezel. Disconnect the monitor from the
wiring harness, remote adjustment board, and ground wires. Remove the fasteners that secure the
monitor frame to its mounting panel. Carefully pull the monitor from the cabinet. Set the monitor in a
safe place. Remove the remote adjustment board from the cabinet and reconnect it to the monitor
before servicing or replacement. Clean the face of the CRT before reinstalling the monitor bezel.
The monitor is a medium-resolution type with a 25-kHz horizontal scan rate. Other monitors may look
as if you can use them for replacements. Yet the screens of different monitor types curve differently.
Use only Midway approved replacement parts.
• 
Network Interface Board
Switch off power to the VGM. Unlock and open the rear door. Remove the back of the Arcade
Computer. Note the orientation of the cables. Loosen the header-mounting screw. Disconnect the
network cables from the board header connectors. Remove the circuit board retention bars. Remove
the board. As you remove the board, handle it only by its edges. Don’t touch the copper traces! If you
aren’t reinstalling the board, store it in an anti-static bag and protective container.
• 
Power Filter Board
Switch off power to the VGM. Unlock and open the rear door. Remove the back of the Arcade
Computer. Loosen the header-mounting screw. Disconnect the cables from the board header
connector. Remove the circuit board retention bars. Remove the board. As you remove the board, 
						

							Servicing          5-9 handle it only by its edges. Don’t touch the copper traces! Use anti-static bags and protective
containers to store the board if you won’t reinstall it.
• 
Power Supply
CAUTION:
 Replace the power supply only with a Midway approved power supply.
Make no substitutions. Otherwise you will void the UL and CE listings on your
video game machine. Non-approved power supplies can pose shock and fire
hazards to players and service personnel.
Switch off power to the VGM. Disconnect the line cord. Unlock and remove the rear door. Remove
the back of the Arcade Computer. Unplug the IEC AC power cord. Inside the Arcade Computer,
disconnect DC power cables. These connect to the hard drive, motherboard and other peripherals.
Remove four mounting screws from the outside of the Arcade Computer enclosure. Lift the power
supply out of the cabinet. Before reinstalling the power supply, check the line voltage switch setting.
• 
Speakers
This VGM has four speakers. One woofer is
behind a grille at the back of the driver’s seat.
Smaller, full range speakers are behind the
marquee. A second woofer is inside the main
cabinet, accessible from the back. Switch off
power to the VGM.
ACCESSING THE SEAT WOOFER.
 Remove
mounting screws and set the speaker grille
aside. Don’t use excess force when removing
or tightening mounting screws threaded into
plastic. Avoid speaker damage by removing
the upper mounting screws first. (Replace
these top screws last.) 
 
ACCESSING THE CABINET WOOFER.
Unlock and remove the rear door. Unscrew
the Arcade Computer mounting brackets.
Disconnect and remove the Arcade Computer.
Unscrew and remove the computer’s wooden
mounting panel. Remove speaker-mounting
screws.
ACCESSING A MARQUEE SPEAKER.
Unscrew and remove the marquee retainer.
Expose the speakers by removing the
marquee glass. Remove speaker-mounting
screws.
SPEAKER REMOVAL. 
Assure proper polarity
by marking each speaker wire (“+” or “Gnd”).
Remove the speaker from the enclosure and
disconnect the wire lugs.  
						

							Servicing          5-10 • 
Video Board
Switch off power to the VGM. Unlock and open the rear door. Remove the back of the Arcade
Computer. Loosen the header-mounting screw. Disconnect the video cable from the board header
connector. Remove the circuit board retention bars. Remove the board. As you remove the board,
handle it only by its edges. Don’t touch the copper traces! Use anti-static bags and protective
containers to store the board if you won’t reinstall it.
• Wheel Driver Board
Switch off power to the VGM. Unlock and open the rear door and the coin door. The Wheel Driver
Board mounts to the wooden shelf behind the gearshift. Note the orientation of the connector and the
other cables. Extract the harnesses from the board connectors. Leave the other end of the ribbon
cable connected to the MagicBus Board. Remove mounting screws from the Wheel Driver Board. Lift
the board out of the cabinet. Handle the board by the heatsink. If you aren’t reinstalling the board,
store it in an anti-static bag and protective container. 
						

							Parts          7-1



	
TM




PARTS
WARNING: 
Use of non-Midway parts or circuit modifications may cause serious injury or
equipment damage! Use only Midway authorized parts.
For safety and reliability, don’t substitute parts or modify Midway products. Substitute parts or
modifications may void the game’s EMC directive or FCC type acceptance.
NOTICE: 
The term VGM refers to the video game machine. 
						

							Parts          7-2
Cabinet Front View
03-8252-5
08-7980
31-3423.1-2
08-7853
03-9932.1 5675-16273-00
04-12760-1
04-12760-2
23-6723 01-15084A-22506
31-3418.2
A-23231 31-3423.1-1 
						

							Parts          7-3
Cabinet Rear View
01-10714
03-8326 
						

							Parts          7-4
Cabinet Joining Details
4700-00033-00B
4701-00005-00
4320-01124-16
04-10112
4020-01100-20