Star Tech Journal
Issue: 1991-January - Vol 12 Issue 11 - Page 6
Atari Pole Position
Switching Supply Substitute
Donald Prince
D&RMusic
Bozeman, Montana
This is a modifzcationfor Pole Position or Pole Position II. It consists of by-passing the existing
linear power supplies and adding one 11 amp switching power supply. Here's how to do it.
PROBLEM
Burnt edge connectors on PC boards, intermit-
tent lock-ups, and other heat related problems.
INFORMATION
The root of these problems are and will always be
the design of linear power supplies. Linear power
supplies inherently have problems with heat
dissipation and efficiency.
The reason for this is that linear power supplies
are always pumping current, thus making them
run hot and build up heat. The more heat. the
less efficient the power supply.
The Switching Power Supply alternately
"switches" the current on and off, at a high rate
of speed allowing less heat build up and more
efficiency. So, if you eliminate the linear power
supply, you solve the heat dissipation problems.
SoLUTION/PROCEDURE
• Remove the two Regulator/ Audio II boards.
Cut the two traces shown on Figure 3, then re-
move Q3 (2N3055) and make sure R29, R30 have
been removed and replaced with wire jumpers, if
you haven't done that modification already.
Refer to the outline on Diagram A. Replace
Regulator/ Audio II boards.
• Now mount the 11 amp Switching Power Sup-
ply (Referred to as SPS from now on) on the
opposite wall as the PC boards are mounted.
• Mount it about 15" from the bottom of the
cabinet. Mount the AC fan close to the SPS. I
mounted mine on the back door by cutting a hole
with a jig-saw.
• Make sure the game is unplugged, then fmd the
J4 connector on the transformer assembly.
Splice in three wires (I used 16 gauge zip cord,
about 9 feet and wire nuts to splice the wires
together) and attach the black and white wires to
the AC terminals of the SPS, the green wire
(earth ground) to the FG terminal of the SPS (I
used spade connectors to connect to the SPS
terminals).
• Connect two wires from the AC terminals of
SPS to the AC fan. Now remove all fuses from the
transformer assembly, including Fl the main
fuse, take a 4 amp slow-blow you just took out
and put it in the Fl fuse holder (Figure 2).
• Go to the J5 connector on the transformer
assembly (the largest one, on the front right
corner) and cut the 2 orange, 2 violet, and the
orange-white wires. Then remove C2, the large
capacitor (27,000uf) mounted on the floor of the
cabinet.
• Cut the wire ties, and remove the cable anchor
on the cabling so you can free the orange and
violet wires you just cut, and the orange and
violet wires that go to P6a and P6b on the
Regulator/ Audio II boards (Figure 1) schematic.
• Take the ring terminal ends of those wires and
connect the orange wires to 12vdc terminal of
the SPS, attach the violet wires to the ground
terminal of the SPS.
• Swap the P6a and P6b connectors on the
Regulator/ Audio II boards. Now attach a wire to
Switching Supply Substitute
Donald Prince
D&RMusic
Bozeman, Montana
This is a modifzcationfor Pole Position or Pole Position II. It consists of by-passing the existing
linear power supplies and adding one 11 amp switching power supply. Here's how to do it.
PROBLEM
Burnt edge connectors on PC boards, intermit-
tent lock-ups, and other heat related problems.
INFORMATION
The root of these problems are and will always be
the design of linear power supplies. Linear power
supplies inherently have problems with heat
dissipation and efficiency.
The reason for this is that linear power supplies
are always pumping current, thus making them
run hot and build up heat. The more heat. the
less efficient the power supply.
The Switching Power Supply alternately
"switches" the current on and off, at a high rate
of speed allowing less heat build up and more
efficiency. So, if you eliminate the linear power
supply, you solve the heat dissipation problems.
SoLUTION/PROCEDURE
• Remove the two Regulator/ Audio II boards.
Cut the two traces shown on Figure 3, then re-
move Q3 (2N3055) and make sure R29, R30 have
been removed and replaced with wire jumpers, if
you haven't done that modification already.
Refer to the outline on Diagram A. Replace
Regulator/ Audio II boards.
• Now mount the 11 amp Switching Power Sup-
ply (Referred to as SPS from now on) on the
opposite wall as the PC boards are mounted.
• Mount it about 15" from the bottom of the
cabinet. Mount the AC fan close to the SPS. I
mounted mine on the back door by cutting a hole
with a jig-saw.
• Make sure the game is unplugged, then fmd the
J4 connector on the transformer assembly.
Splice in three wires (I used 16 gauge zip cord,
about 9 feet and wire nuts to splice the wires
together) and attach the black and white wires to
the AC terminals of the SPS, the green wire
(earth ground) to the FG terminal of the SPS (I
used spade connectors to connect to the SPS
terminals).
• Connect two wires from the AC terminals of
SPS to the AC fan. Now remove all fuses from the
transformer assembly, including Fl the main
fuse, take a 4 amp slow-blow you just took out
and put it in the Fl fuse holder (Figure 2).
• Go to the J5 connector on the transformer
assembly (the largest one, on the front right
corner) and cut the 2 orange, 2 violet, and the
orange-white wires. Then remove C2, the large
capacitor (27,000uf) mounted on the floor of the
cabinet.
• Cut the wire ties, and remove the cable anchor
on the cabling so you can free the orange and
violet wires you just cut, and the orange and
violet wires that go to P6a and P6b on the
Regulator/ Audio II boards (Figure 1) schematic.
• Take the ring terminal ends of those wires and
connect the orange wires to 12vdc terminal of
the SPS, attach the violet wires to the ground
terminal of the SPS.
• Swap the P6a and P6b connectors on the
Regulator/ Audio II boards. Now attach a wire to
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