Stargate

I have my Defender game working 100% but I've been playing around with the cabinet. By chance I saw a Stargate game (non-working of course) come on eBay at a decent price (okay, $250) that was local, so I put in my bid and waited 10 minutes to see if I won it (I told you it was by chance). So now I'm the new owner of a non-working Stargate game.

I went to Linden NJ (about 30 minutes away) to pick up the game early Christmas Eve morning with one of my daughters. The game was in the shape it was advertised so no complaints there. We hauled it home in the Suburban (it's really good having a Suburban when you need to move video games).

So the Stargate is in the basement right next to the Defender. My priority now is to get Defender put back together, I'll deal with the restoration of the cabinet later. Since Stargate uses the same monitor as the Defender (a GO7-CBO), I was able to swap monitors to see if the Stargate monitor was working. The good news is that the Stargate monitor is good but it does need a cap kit. So the problems are deeper (I suspected that since there was no sound during the POST) and will require some work.

So I just ordered a standard set of supplies when dealing with a Williams game, first a GO7-CBO cap kit and a "get well kit" for the linear power supply. Yes, the Stargate still has it's original power supply - no switching, and I'm going to keep it that way if at all possible (by the way the supply LEDs are all lit, so the supply probably isn't the problem). I also ordered a set of RAMs, the 4116's seem to go out quite commonly with these boards.

The cabinet of the Stargate isn't too bad. Like most cabs there are big holes from where lock bars were installed to secure the coin box. I have to rework the power cord. My plan is to use an IEC power entry module like I did for the Ms Pacman.

High Score for Defender

I did some more work on the Defender game today. My first priority was to get the high score kit installed. This is another item I purchased from Bob Roberts (www.therealbobroberts.net) that replaces the three AA battery holder that comes stock on a Defender board.

Invariably having AA batteries on a board causes all kinds of problems when the batteries leak. For some boards the damage is extensive and renders the board unusable, but for mine the damange was rather minor. But the battery back didn't work as the terminals of the battery holder were corroded.

The solution is to remove the AA battery holder an replace with a CR2032 lithium holder & battery. This is relatively minor surgery. Now my Defender keeps it's s/w configuration settings and high scores. I've read some postings on the net that claim the lithium battery will be drained pretty quickly. I don't know why this would be the case. the CMOS 5101 RAM has a standby current of about 5 uA, this is probably not a whole lot more than the self-discharge rate of the lithium battery. Looking at the schematic I can't see where else there might be a current loss. I figure the battery will keep high scores for about the same amount of time as the shelf life of the CR2032, which is probably 10-15 years.

The speaker for the Defender is ripped and I have to figure out what to do, re-cone this speaker, send it out for re-coning, or just get a replacement. I can get a new speaker for about $21, but re-coning will cost at least $40. But then again a re-coned speaker is more "original".

I started filling the in the dents and holes in the cabinet. I'm staying away from any work that will commit me to totally refinishing the cabinet as I haven't decided if I want to go that far, the side art isn't in bad shape, but there are spots where it's been painted over in a poor attempt to hide scratches.

Defender lives

I got the bridge rectifier from Bob and installed it. The +5 came up immediately. I completed connecting all the components on my work table and fired up the game. No sound, but I got a "rug pattern" on the GO7 monitor. Since this game used to work I suspected that when the power supply went on the fritz it took something with it.

The most likely suspect were the 4116 DRAMs. These were a pretty standard part "back in the day". What's annoying about these parts is they require 3 voltages to operation, a +5, -5 and +12v supply. I also recall (from back when I had a TRS-80 that used these same memory chips) that these chips were finicky regarding how the power is supplied. My guess was when the +5 went out it took the RAM chips down too.

Luckily you can still get these chips, so I ordered a complete set (24, for 48K of RAM) from Bob Roberts. They came in today. I pulled all the old chips and put in the new. I turned the system on and Defender came up.

I'm not playing the game yet I still have a couple of issues to address. I need a new speaker, the one in the game has a rather large tear, though it still sounds good. The bigger problem is I need to fix the battery backup on the game. This is a common problem, when batteries leak their acid tends to corrode the board and eventually the battery holder and traces are eaten away. That's the case for my board so I have some work ahead of me to clean this up.

Battery backup for a Defender game is important, it's not just about the high score. Defender and other Williams games use software configuration. In other words the configuration of the machine is stored in memory (RAM), and if that memory isn't backed up by battery it will "lose" the configuration and the game will be unplayable until it's re-configured. This is a major pain in the ass to perform every time you want to play a game.

So the solution is to either fix the battery holder (AA type batteries), replace with a Bob Roberts replacement (Lithium battery) or try to find the SimTek replacement that swaps out the 5101 with an NVRAM - the no battery solution.

For now I need to move on to the cap kit for the GO7 and make decisions about how far I want to take restoration of the cabinet.

On to Defender!

The Ms Pacman is doing very well in its new home (my eldest daughter's bedroom). There was an issue where the colors of the monitor were off, but re-routing the internal power lines cleared up the issue.

My son and I moved the Defender game into the house. I then proceeded to pull all the guts out of the cabinet (it's an upright) and lay them out on a table. I have confirmed there's an issue with the power supply, it appears the 35A bridge rectifier (BR1) is shot so I've ordered a replacement (& some other parts) from Bob Roberts.

The GO7 monitor is filthy so I've spent some time trying to clean it up. I think I need to hault it out to the garage so I can use my air compressor to clean it up.

Yesterday I used a sponge and some soapy water and cleaned the now empty cabinet inside & out. There's some repair work needed on the cabinet, the previous owner had installed a standard light switch (the kind you have in your home) and cut a rather large hole in the cabinet. After these repairs are done I'm considering purchasing a set of stencils (www.gamestencils.com) and repainting the exterior.

The priority is the electronics. With the parts I ordered from Bob I should be able to get the power supply working. Once the game is operational, I'll re-cap the GO7. Then I can move on to the aesthetics of the game.

Ms Pacman Complete!

Finally, the "restoration" of the Ms Pacman game is complete and the game has been moved up to my daughter's room. I learned a lot of things in fixing up this game (such as there's no such thing as a "cheap" game when you are restoring).

Notice the 1/2 player buttons above the coin door. These are not "Pacman" authentic but were part of the cabinet as I received it. I opted to leave these buttons in place and keep them functional.

You can see in the picture that there are holes for the speakers. Once again not "Pacman" authentic, but this is how the cabinet was originally configured.

There's one thing that I did that was "wrong". Player one is to the right of the coin door, not the left as it should be in a true Pacman game. I'm also missing lights behind the control panels, another item that wasn't present in the game as I received it. I needed to get this game done so I could move onto other projects, and I can always circle back and includes lights when I have the time.

I had one major set back right before I finished everything. Upon closing up the game for the last time the neck board of the GO7 monitor was cracked. This is another indicator that this cocktail cabinet was not originally a Pacman, the neck board had left scratches on the back of the coin box frame.

This really bummed me out, I figured the neck board was shot and I had to find a replacement. Looking on eBay I saw some board sets for around $90. I opted to see if I could repair the neck board since I had nothing to lose.

Fortunately the neck board is single-sided, so I identified the breaks the traces and soldered up bridges using solid #22 wiring. This worked very well and I restored the monitor back to operation. You can see the result to the left.

While I had the system open I figured I'd address the edge connector issue. I had purchased an edge connector repair kit from Bob Roberts but since my connectors were in pretty good shape I was hesitant to modify the board. During one of the repair sessions the trace for the +7AC tore up (I'm sure it was in bad shape), so now I had no choice. Now I have solid connections as well as a newly rewired edge connector.

Now the only issue with the monitor is that the fan and transformers are unshielded so there's a slight wave. This "wiggle" isn't present when I have the game open, so I'm guessing it's due to the proximity (inches) of the components (transformer & fan) to the monitor. I don't have a lot of options in repositioning internal parts, so I'm going to live with this issue for the mean time.

The game is set to free play and the volume is at a tolerable level. So far the internal temperature seems to be in a good range and the fan, while noisy, isn't annoying. The monitor could still use a good tuning just to get the colors and sizing right, but it's playable.

Now I have to decide which game to fix next, I have a couple of options:

Defender - there's something wrong with the power supply, hopefully this would be quicky.

Battlezone - this game plays blind. I like vectors and I'd really like to get this one up and running.

Missile Command - used to work but now the screen is just showing test patterns. This game also needs some work on the trackballs, they aren't playing too well.

Space Invaders - no sound and the cabinet has water damage.

Defender is the game I have the most fun playing so I'm going to start work on getting this game back into shape. Hopefully it won't take long.

I have to get more games working. I have a self imposed limit of having only 2 non-working games, otherwise I can't acquire any new games. Space Invaders technically works, but with Defender on the fritz I have more than two (Battlezone & Missile Command) that don't work, so no more acquisitions.

For now Ms Pacman is in my eldest daughter's room. I have to admit it looks pretty good considering this was my first "restoration". This was not cheap, I'll post a complete break down of parts, but basically the sunk cost into this game is about $800. There were opportunities to reduce costs but the majority of the expensive items were related to creating an "authentic" PacMan/Ms Pacman game - purchasing overlays & underlays.

New harness

After some research I figured the most likely cause of the screen problems the Ms Pacman was experiencing. These are known as "hum bars" and generally can be traced back to poor power/grounding. The easiest solution is to replace all the fuse holder blocks to clean up connections. The second solution is to replace the edge connections.

I swapped out the fuse blocks and the problem remained, so I moved on to the more difficult task of rewiring the edge connector. Once again with another order to "The Real Bob Roberts" and I had two options in hand. One was a "hum bar fixup kit" that provided a new 22/44 pin molex connector. The second option was a completely new wiring harness.

The parts arrived 2 days later and started with the easier of the two fixes, swapping the molex edge connector. One by one I removed wires from the old edge connector and connected them to the new edge connector. For the power connectors I beefed up the wiring (to 18ga) and soldered the connectors to ensure a better connection. I cleaned up areas of the wiring where the previous owner had cut into wires to get access to ground.

This did the trick, the hum bars are gone. Based on my dialog with Bob, the harness my game has is not a standard Pacman/Midway harness, it's pretty clear someone retrofitted a Pacman upright into this cocktail cabinet.

So I'm almost ready to button up the game. I added a fan (there's a mounting for one, it had been removed) and rewired the A/C internals as noted in my earlier blog. My next task is to neatly install the wiring and install the new cocktail table glass with the new underlay. I'll include some pictures in a future post.

Getting there!

Today was a big day for the Ms Pacman day. In the past 2 weeks I've recovered the cocktail table using vinyl laminate I purchased from PartsExpress.com. For $20 you get 18 feet x 25", which is more than enough to cover the game.

This was my first time working with this stuff and it didn't come out perfect, but it's a lot better than the previous covering. I also put on new t-molding, and that came out pretty good. Overall the game looks pretty good.

Today was my big push to clean up the internal wiring. I opted to put a new power entry jack, an IEC connector. This is the connector type you see on virtually every desktop computer (see the picture).

I also added an "interlock switch" so if you open the cocktail table up the power is switched off. This is in series with a main power switch. And for added measure there's a fan, running of 120vac, to keep things cool. The cabinet has ventilation holes for this type of fan, but the fan was missing from the game.

I put everything back into the cabinet and then powered it all up, everything works! The only issue is that there is a slight "wiggle" to the display. So I've pulled everything apart and now I'm debugging this problem.

So I'm very, very close. Once I get rid of this wiggle I can put everything back into the cabinet and tie up the wiring harnesses.

So I have ordered some additional parts from Bob Roberts, the important one being a new filter capacitor for the GO7 B+ supply. I also ordered a shielded speaker, the existing speaker is unshielded and it's proximity to the monitor may cause issues.

I'm anxious to wrap up the Ms Pacman. I have several other games that need to be fixed (a Battlezone with monitor problems, a Defender with a power supply issue and a Missile Command cocktail that just isn't working any more).