Howdy folks! I’ve been spending every free minute I’ve had working on the Vidiot board for my Baby Pac-Man. The last thing I was going to try was to change the 10.7386MHz crystal directly above the video processor chip in U16. The crystals I ordered came in. I put a new one in and it didn’t fix the problem. I was still getting only 8 flashes on the LED during bootup.

In desperation, I ordered new chips for U7 and U8 from Bob Roberts, which should be here tomorrow. I also ordered new RAM earlier today. I had changed about half the sockets on the board with new ones. I figured while I was waiting for parts, I’d keep changing the rest of the old sockets. I started with the socket for U12, which is the ROM that contains the programming for the video portion of the self test. That did nothing. I moved on to the socket for U11. When I pulled the plastic part of the socket off the board, I noticed that the pins were very corroded, even though the socket right next to it was fine. Popping a new socket in U11 fixed the problem, and I got 10 flashes at bootup. I can’t tell you how excited I am. I actually danced a jig, and I’m not Irish.

Here’s a video of it working. Keep in mind it’s hard to play while holding a camera in one hand. The cabinet is very tilted, so the pinball portion doesn’t play quite like it should.

Now, next on the list is to change the rest of the sockets for preventative measures. Then I’ll do a cap kit on the monitor and hope that my new cabinet gets here sometime this year.

Konnichiwa! Checkout this awesome The Simpsons Movie promo poster:

It was hanging in a Mister Donut shop in Japan! Mister Donut is long defunct in the US, but is still around and pretty big in Japan. This was advertising Simpsons donuts they were selling to tie in with the release of the movie in Japan. I have a friend that is living there, and he scored this for me.

Here it is in context with the rest of the stuff on the wall:

Directly below it, are 2 small ads they had on their napkin holders:

Writing this is making me want donuts….hmmm….strange…..

If you ask this lady, the answer is when you are in a pine box:

I snapped this at the fabric store while I was with my wife this past weekend. This senior is still stripping AFTER 25 FREAKIN’ YEARS! I wonder what strip club in hell she dances at? If she’s still giving lap dances, I hope she remembers her Depends. This woman should NOT be stripping. She should be in the kitchen baking me cookies.

Hey. I’ve been spending a lot of time the past week or so working on the Vidiot board from my Baby Pac-Man. The last thing I mentioned here is that I was getting 8 flashes from it on boot. You should get 10 when everything is working properly. 8 usually indicates that the TMS9928 chip in U16 is bad. I ordered (2) NOS replacements from Jeff at Classic-Arcades.com. I don’t think they are listed on his site, but he mentioned he had them in the RGP newsgroup. I figured it would be good to order an extra because they are hard to come by.

I waited patiently for the chips to arrive, and popped the replacement in. Unfortunately, it still had the same problem.

I’m suspecting the crystal that controls the timing for U16 might be bad. Someone mentioned they had that problem (in the RGVAC newsgroup?). I don’t have another crystal, so I ordered some. I’m hoping they’ll be in tomorrow. In the meantime, I tested just about everything I could on the board. I won’t bore you with all the details, but let’s just say I spent a ridiculous amount of time working on it this past weekend. I worked on it most of the day Saturday, up until about 4AM Sunday. Then, I slept a few hours and went back at it again. (Yes, I’m insane).

One of the things I noticed is that there was a capacitor (C87) that was broken off the board:

Seeing this made me excited, because it was obviously wrong. Changing it didn’t do squat to fix the problem with U16, but at least its replaced now.

I figured I would replace the rest of the old sockets with machine pin sockets in case one of them was making a crappy connection. I started with U8, because that’s the chip that is reporting that U16 is bad. By the time I got to working on this, I had lost a lot of sleep. I’m not sure if that factored in or not, but I really screwed up a trace. I usually cut off the old sockets, exposing the pins. Then, I grab each pin with pliers, heating the solder until it melts, and the pin pulls right out. On one pin, the trace came right up with the pin:

This is the first time I’ve ever lifted a trace like that…I hope it’s the last! I repaired it on the underside with a 24 gauge solid core jumper:

I told you I wouldn’t bore you with all the details, but I guess I lied. I’ve been keeping a list of everything I’ve done in notepad on this board…here it is in excruciating detail:

1. All voltages on board OK
2. Changed socket for U16 and put new chip in….still N/G
3. Every pin on U16 is connected to where it should be, via continuity test
4. C73 is OK
5. C62 & C63 seem OK (they surround the Y2 crystal)
6. Tried to get a pulse on crystal Y2 via logic probe and couldn’t…not sure if it should pulse or not.
7. Changed C54 - no effect
8. Diodes are OK: CR1, CR2, CR3
9. C87 was broken off…replaced it  - didn’t fix problem
10. Pulled all socketed chips, cleaned, reseated
11. Swapped 2114 RAMs in U13 and U14. No change…put old ones back.
12. Changed C92
13. Changed C107
14. Changed C109
15. Tried a 10mHz crystal from Kangaroo….N/G
16. Changed C62 & C63…N/G damn it
17. Changed socket for U8.

I’ll let you know what happens when I put the new crystal in…

Good evening. I was planning on testing my Baby Pac Vidiot board “on the bench”, via the instructions at Pinrepair.com’s awesome Baby Pac-Man page. I ordered some 12 pin and 2 pin .156 Molex in-line housings from Bob Roberts. Because they were so cheap, I ordered some extra connectors, including some headers and sets of monitor connectors. Here’s what I got today (picture taken after I ate the Moon Pies that he included in the box)

The 4 small bags in the upper left that are the same size are sets to make monitor connectors. They contain (1) 3 pin .156 housing, and (1) 6 pin .156 housing. Below those on the left are .100 headers that can be snapped to get the size needed. Below that are 24 pin .156 headers that are also “snappable”. The right side shows (4) 12 pin .156 housings, and (4) 2 pin .156 housings. That’s what I’m using for this tutorial.

OK…I needed an easy way to hook up alligator test leads like this (from Rat Shack)…

…to header connectors on my Vidiot board like this:

That image shows a 5 pin header. The Vidiot board has 12 pin and 2 pin headers, but you get the idea. I can’t just hook alligator leads to these because they could touch each other. It would also be difficult to put 2 clips right next to each other in that small footprint. I decided to make some test connectors that I can reuse…there may be a better way to do this, but this is how I made mine.

First, I took some .093 molex socket connectors that I got from Bob Roberts and opened them up by forcing a small screwdriver in the end and wiggling it around. This pic shows one of those pins, before and after.

I crimped the end on an 18 AWG wire. Then, I took some shrink wrap tubing, and cut it so it would be a little bigger than the connector.

Next, I slid the shrink wrap tubing over the end, making sure it was sticking past a little bit. After heating it with a lighter, here’s what it looked like:

The idea with this is to have a connector I can easily clip a lead to while still being insulated, like so:

The 2 pics above show the first connector I made for this. The end of the shrink wrap tubing didn’t shrink tight enough around the wire end. For the rest of these, I put a small piece of narrower shrink wrap tubing on that area to build it up a little thicker before putting the wider tubing over it.

Here are 2 finished test connectors ready to go. I alternated the length of the wires so adjacent connectors won’t have any chance of touching.

Hey! I just found this writeup on Geekologie.com about some very cool arcade themed cupcakes made by Flickr user hello naomi. In case you don’t read Geekologie, here they are:

Hey there. I have an order in with Bob Roberts for some connectors so I can test my Baby Pac Vidiot board “on the bench”. The Vidiot board is the main board for the video game portion of Baby Pac-Man.

I changed the rest of the lamps in the playfield this morning. I couldn’t wait to get the connectors to test the Vidiot board, so I figured I would hook all the boards and playfield back up in my old cabinet to test it that way. Here’s a video showing what the game is doing when you boot it up:

When it first comes on, it tries to play the startup music but it is a bit broken up.

It looks like I have one bulb out that I’ll have to checkout. The playfield looks very cool lit up and blinking like crazy.

The video on the monitor is a bit screwy. It’s only showing blue. When you play the game, it won’t switch over to the pinball portion. After the game is on for just a little bit longer than shown in that video, the monitor changes and just shows blue bars:

According to the info on Pinrepair.com, the Vidiot board’s LED should flash 10 times to indicate everything is working properly. On mine it only flashes 8, which usually means the TSM9928 chip in socket U16 is bad.

I pulled the chip, and the legs on it were really dirty…almost black. I thought for sure I took a picture of it before I cleaned it but it looks like I didn’t. Here’s a pic after I cleaned the legs with a fiberglass sanding pencil:

I popped the chip back in, and it still didn’t get past 8 flashes. I figured maybe the socket might be bad, so I changed that as well. I didn’t have a 40 pin socket, so I used a 24 pin, and cut down a bigger one to make up the difference.

Changing the socket didn’t help, but it probably should have been changed anyway. It looks like I’m going to need to replace that chip. They are supposed to be very hard to find. Bob Roberts had them listed on his site, but I contacted him and he just sold his last 2. ArcadeChips.com has them. I’m waiting for an email reply to see whether or not I’ll order through them.

One thing kind of interesting is that these chips were also used in Colecovision consoles. If I can’t find a replacement chip I’ll have to try to get a Colecovision on eBay and pull that chip from it.

When I do replace the chip, I plan on putting a heat sink on it. I’ve read that the chip gets very hot and a heat sink should help.

Yo…it’s Saturday night. I just got back from seeing Cloverfield. It was pretty good. If you haven’t seen it yet, the monster looks just like Yogi Bear, only taller. He runs all over Central Park stealing pic-a-nic baskets and killing people. I snapped this pic with my cellphone in the theater.

The other day I followed info on testing my MPU board that I found on Pinrepair.com. Whoever setup that site should win the Nobel prize for pinball repair. Here’s the main page for Bally MPU boards.

I followed their advice on cleaning up corrosion, and proceeded to this area that explains how to test the MPU board “on the bench”. I don’t really have a bench…I’ve been working on my computer desk. That page explains that you can test a Bally MPU board by hooking it up to 12V and 5V. I used a power board that I setup for my Pac-Man project. It has a switching power supply mounted on it. I followed their instructions, hooking up 12V, 5V, and ground. When you power it on, you should get 5 flashes, which are explained here. Here’s a video of that in action.

After doing that test, I was pretty psyched. I kept reading and found out that normally a Baby Pac-Man MPU board should flash 6 times to indicate everything is OK, and then it goes into attract mode. The test that triggers the 6th flash fails because the first thing it does is look for the presence of 43V, which is missing. I followed more instructions on that site which explained how to trick the board into thinking the 43V is present so you can finish the self test, by putting a jumper from one leg of R23 to one leg of R17 (read their site for exact instructions). OK…so I hooked up my jumper, and this is what happened:

The LED lit solid with no flashes. It took me a few minutes to notice that I screwed up, and hooked the jumper to R2 instead of R17. They are very close together and the labeling on the board is a little confusing. Hoping I didn’t fry anything, I moved the jumper to where it should be, and tried it again:

The damn thing actually works! Next step will be to test the Vidiot board. I ordered some Molex connectors from Bob Roberts so I can use them for that test….hopefully I’ll get some more moon pies with them.

BTW - The empty Baby Pac-Man cabinet that I bought in Kentucky has been picked up by a shipper finally. I don’t have a scheduled date for when it will get here, but I’m hoping it will be soon.

This is a continuation of the post I wrote last night in case you couldn’t figure that out by the “Part II” in the title. (DUH!)

I removed the old rechargeable NiCad battery from my MPU board and cleaned up all the damage it caused. The battery is not really needed. It’s there to maintain high scores, settings, and book keeping info. I figure high scores and settings are important enough to warrant putting in a replacement for the battery.

Someone had already done something similar (but different!) on my Defender. I’m guessing they followed this tutorial by Bob Roberts. For that, they put a shiny round lithium battery in as a replacement…similar to a watch battery but bigger. I was thinking maybe that would be the route to go for this, so I searched the RGP and RGVAC news groups for more info.

I figured that maybe a lithium battery would be the best bet because they last so long. The alternative is to setup a remote mounted (3) AA battery pack. Bob Roberts has a tutorial for this as well (because he rocks). No matter which way you do this, if you put in replacement battery(s), a blocking diode needs to be put in-line before the battery pack to keep the MPU board from sending voltage to the batteries to try to recharge them.

On some posts in those aforementioned newsgroups (50 cents please), they mention that lithium batteries can be dangerous when hooked up improperly and can start fires. I’m not sure about this, but I figure that if I did put a lithium battery in and the blocking diode crapped out, my Baby Pac-Man might end up a big smoldering pile of ashes. Because of this (and because so many people seemed against lithiums for these boards) I ruled this option out. I don’t need any visits from Smokey the Bear, thank you very much.

There is also another option that I read about, where you can use a special capacitor that will hold the charge similar to a battery. With that method, you have to make sure to power the game on at least once every 6 months (I think). This sounds pretty cool, but I figured I would just go with the AA battery option following Bob’s tutorial. I ordered some diodes from him and a battery holder for $1.00, along with more lamps for the playfield. Here’s what I got:

Before I did anything, I ate the moon pies. Then, with my sugar buzz going strong I hooked up the battery pack per his instructions.

He mentioned putting a connector in-line so you could remove the board without having to remove the batteries. I thought that was a good idea, so I used some of these from Rat Shack:

I crimped them using my HT-1921 crimper that I got from Bob awhile back. He’s got a tutorial on crimping here.

I wrote the polarity for each battery with a sharpie, and added some zip ties in a couple places so if the wires get pulled, they don’t put any pressure on the solder joints.

One other thing I did a little differently - I didn’t use wires to connect the batteries. I’m talking about the 2 small wires seen here in Bob’s pic:

Instead, I turned the terminals down…

…and soldered them together:

If you do this, just be careful none of your solder drips down and touches the metal housing because it does conduct.

Here’s the other end connected to the board:

I ran my wire around the back, through that middle hole, and tied it off again through itself so pulling on the cable won’t pull on the solder points.

The last thing I did after hooking the batteries up was a test that I think I read about on Pinrepair.com. The whole purpose of the batteries is to keep a 5v (ish) charge on the RAM chip in socket U8 when the game is powered off. To make sure it was doing what it’s supposed to do, you can check the voltage on that chip with a meter by putting the red lead on the power pin of the chip (pin #22), and then ground the black lead. Here’s that test, showing it’s doing it’s thing.

Stay tuned for the exciting conclusion….

Wow…I haven’t posted in a week. Time flies when you are on acid repair duty! Because I’ve saved up info and pics over this week (and so I don’t bore you with a giant post), I think I’ll save some of it to write tomorrow and the day after. Here’s part one.

Before I start babbling, I just want to let you know that most of the info I’m going to bring up was figured out by others much smarter than I (Pinrepair.com, Bob Roberts, etc…).

Baby Pac-Man has 3 boards. The main pinball board is a slightly modified Bally “-35″ MPU board. It had a rechargeable NiCad battery mounted on the board that overtime leaks all over the place (like your incontinent Uncle Larry). If left on the board it can cause major corrosion damage that needs to be repaired. The corrosion follows the traces and spreads quickly (like your Aunt Gladys?). My MPU board had this damage big time.

I followed this great tutorial from Pinrepair.com on cleaning battery corrosion damage. They recommend replacing any components that look corroded. I bought a kit on eBay for $10 that contained most of the parts that usually go bad on this particular board from corrosion. Here’s what it looks like:

I scraped and sanded at the corrosion using 100 grit sandpaper, a Radio Shack soldering tool with a scraper on one end and a wire brush on the other, and a fiberglass sanding pencil:

The scraper worked good for very loose stuff. The sandpaper worked good to get most of the rest of the corrosion off the large ground traces, and the fiberglass pencil was awesome for cleaning up small areas (solder pads, etc…).

Click here to buy one of these. Click here for the refills for it.

A paint brush comes in handy for brushing off all the crud while you are working.

If you compare this pic to the second one in this post you can see exactly where the corrosion stopped:

The shiny spot that looks like the bottom of Texas was fine. I just scraped it a bit to see the difference. All the gray/green/blue crud below it is corrosion. Here’s the same area after cleanup:

Basically, I went through the entire board cleaning up the corrosion and installing the parts that came with the kit. Here’s the end result front and back.

Stay tuned tomorrow for the battery pack hookup (I bet you won’t be able to sleep now!).

To be continued…