Jeff Rothe of Rotheblog just posted a story on some Ms. Pac-Man stencils he purchased. This is a nice article explaining how stencils are made for arcade restorations. He also has other articles showing how to properly restore a Ms. Pac-Man cabinet. I’ve not used stencils yet for any of my restorations, but I may do so on my Stargate Multi-Williams project I plan to build.

Rotheblog Ms. Pac-Man Stencils

After working so much on my Tron lately, and not quite getting to 100% working status, I decided to take a break and work on something else. I have a Pole Position 2 that I want to get working, so I can either trade it or sell it to make room for my Donkey Kong 2 project. The last I left this cabinet, it was all taken apart to clean up all the pieces before reassembly. I needed to repair the monitor because it had a broken neck board. And finally the PCB did not work (what else is new in Pole Position stories).

Well, I did the neck board repair over Christmas vacation a few months ago. I will post some pictures of that soon. Also completed a power supply rebuild to get two working AR2 boards. I have a few pictures of this repair below. They both were in need of serious repair, having some of the common symptoms of failed AR2 boards such as burned out resistors from the Sense circuit drawing too much power from the board. These boards were made to monitor the voltage drawn from the PCB they are powering and automatically increase the voltage to ensure the PCB runs properly. This is a great concept, but Pole Positions were so poorly designed that they often would draw more power than the AR2 boards could supply without burning up. This would also cause the PCB edge connector on the Pole Position boards to burn up. There is a quick modification that can be made to disbale this ‘sense’ detection, preventing the AR2 board from automatically adjusting the power output.

This week I decided to attack my PCB. The first problem with the PCB was that it did have the classic “edge connector burn” from the AR2 board. I needed to repair this, and do a few other modifications to “bullet proof” the game to prevent future failures.

Burned up resistor on the AR2 board – common!

Disabling the “sense” circuit is just a couple quick jumpers on the back of the nine pin connector

Completed AR2 boards!

Edge Connector Repair

The common repair for a bad edge connector is to just lay down a line of solder to replace missing connector contact pads. That is obviously what the previous owner of this game attempted. This is a very short-termed repair, as it really does not allow for a clean connection. I decided to buy an edge connector kit from Bob Roberts. This kit comes with a female edge connector with solder pins, and a male-to-male edge connector adapter. Basically the concept of this is to solder the female connector over the existing burned-out edge connector on the PCB, then put the M2M adapter in it to leave a male edge connector on the PCB. Since the Pole Position had less pins than the new connectors in the kit, I was able to cut down the adapter to allow wire ties to hold it in the female connector. Hard to explain, but easy to show in the pictures below:

Burned edge connector on the PCB

Burned edge connector solder “repair” removed.

Bob’s repair kit.

Female connector in place over the old edge connector, ready to solder on.

Needed to trim off the excess Male connectors before placing it.

Finished repair.

Another view of the finished repair.

Power Distribution Modification

One of the most recommended fixes I found on the Internet was to distribute the incoming power to the PCB to the various “test points” instead of just from the edge connector. This would allow the power to be more consistent throughout the board, and to cut back on the power draw over the edge connector (remember the burn?). To do this, I soldered wires for the +5v and Ground to as many test points as I could find marked for this. I then ran all of these wires into a molex connector to allow me to remove the board easily. I’ve already had to remove the board 20 times or so, which proves this molex connector idea was a good one! From that connector, I ran a mating molex connector to a terminal strip which I wired directly to the supply voltage in the wiring harness.

Here are some pictures:

PCB with powr wiring soldered onto the test points.

Molex connector and terminal strip used to send the power to the power wiring on the boards.

All connected and ready to go!

Other Repairs to the PCB

There was some visible damage to the PCB. I had to repair some traces that were burned up as a result of the power problems it had. Also had to replace a few smaller components:

Bad trace

A couple burned components repaired.

I wish everything I did so far was enough to fix it. My first attempt at placing it into the cabinet resulted in the following:

Hey, at least it got power! I then adjusted the power supply to get +5v as close as I could, which was easy to do across my terminal strips. Here’s what I got:

Gave me a RAM 6 error. I had a fellow KLOV collector send me a nonworking Pole Position PCB last week in preparation for this repair, so I swapped out the RAM 6 with it. Placed it back into the cabinet and I got:

Another RAM error. RAM 40. I went ahead and swapped that RAM and got the same error again. Before going crazy trying to figure it out, I decided I should check the voltage again. It was low. I then adjusted it again, and immediately heard the game boot up! Here’s the test screen showing all my RAM and ROM was OK, and a screen shot of the game:

However, if you notice I am getting some graphics corruption on the background objects like the mountains and amusement park. Went ahead and tried to swap out some of the custom Atari IC’s that the instructions said contribute to that circuit but got nowhere. I think maybe my 6N Video ROM may be corrupt, even though it passes the self test. Here are a couple more screen shots to show where I’m at:

Finally, I replaced a few other components that were damaged from the battery failure on the CPU board (another death blow to Pole Positions). I had a few new chips, and the rest came from the extra boardset I had. Here’s a quick shot of the bad chips – notice the corrosion on the pins of the ICs:

I had to remove the Optical Sensor from my Tron Rotary Controller PCB. It was cracked and needed replaced. So I thought I might as well show how I did it. I was told that this component was very hard to remove, so I figured I should take extra care to make sure I can pull it out without damaging the board.

Tools Required:

• Soldering Iron
• New Solder
• “Solder Sucker”
• Desoldering Braid or “solder wick”

The following needs to be done with each pin of the component

1. Flow a slight amount of new solder onto the pin. This will help loosen up the old solder. Don’t put too much on, or it will be drawn down through the PCB hole and lock the component in from the other side.
2. Immediately remove the solder with the solder sucker. This is done by removing the soldering iron from the melted solder over the pin, quickly covering the pin and melted solder with the solder sucker, then pressing the button on the solder sucker. This causes the spring action of the solder sucker to suck all of the melted solder away from the pin. If this is done right (which takes a little practice) then there will be little if any solder left over.
3. Use the soldering iron to hold a small amount of fresh solder wick over the pin to draw out any remaining solder from the pin
4. Finally, GENTLY remove the component. There may still be some sticking of the pin to the contacts, so use the soldering iron to hit any stuck pins until they move freely. This is the toughest part, especially with components like IC’s that have rows of pins and can’t flex.

Here are some pictures that I took:

“Solder Sucker”

“Solder Wick”

Solder Sucker removing solder from hot pin

Using the Solder Wick to remove residual solder from the pin

Close-up of the pins after solder removal

Success! The component has been removed.

Here’s what the component looks like after removal. The pins are in great shape with no damage.