My Ms Pacman Project

[JeepMonkey]

04/03/04

Browsing craigslist I came across a nonworking Ms Pac listed for $150.  The ad said "I think it just needs a fuse".  I am sceptical when someone says it needs a fuse.  Genrerally if you are knowledgeable enough to track a problem to a blown fuse, you would replace it.

So I went by and took a look.  The art was in good condition, control panel had a 1/2 inch rip, the monitor bezel art was in great shape, and the marque is very good.  Unfortunately it had no back door.

The guy powered it up, but the only sign of life was an electrical hum coming from inside the cab.  Monitor did not turn on, no lights turned on at the coin or marque.

The guy said that it stopped working a a couple years ago.  Apparently an arcade resto guy came by for a garage sale and got it working in "two minutes".  It worked for another year, then died again.

I have been looking for a classic and a project, so I bought it.  I work as an Electrical Engineer with an emphasis on industrial controls, so I feel confidant rolling up my sleeves and getting my hands inside the cab.

[JeepMonkey]

04/04/04
Work Day 1

The guy I bought the cab from gave me a rolling cart made out of angle iron and four casters.  I am sure glad I took it.  Moving the cab is so much easier now than lugging it around on the floor.

Work done:
Took pics inside and out.

Vacuumed the inside.  Dirty, but not terrible.

Powered up the cab.  The door switch was held shut by electrical tape.  Again, only an electrical hum and whine sound from the monitor are theonly signs of life.  No light at the marque, coin door, no lights at all.

Wiped the outside of the cab down with a paper towel to knock of some of the dust.

The hand holds on the back were filthy, so I decided to take them off to be cleaned later.  Looking up through the slits in the hand holds I saw there was a speaker mounted just above the left hand hold.  Turns out it wasn't mounted at all and fell down into the bottom of the cab and onto the garage floor.  I have a felling there is only supposed to be one speaker.  It looks like someone just daisy chained in a second speaker.

Last I checked the four fuses that I could see.   I was not happy.  The paper next to the fuses called for two 12V 1A fuses and two 7V 5A.  The fuses I pulled out were not blown, but I found one 5A, one 15A, one 20A, and one 30A.  My first thought is that this thing was blowing fuses and someone kept putting in bigger fuses until they stopped blowing.  Hopefully there is not a short somewhere causing fuses to blow.

[leapinlew]

 

[JeepMonkey]

04/05/04
Work Day 2

Bought fuses and a multimeter.  My last multimeter was loaned to a friend and came back dead.

Changed out the four wrong fuses with the correct fuses.  To my suprise then didn't blow.  This is a good sign that there isn't a short.

I checked voltage across the coin door lights and got 12VAC.  I replaved the two lights with two new lights I bought for another cab and they turned on.  Hurray, a sign of life.  Note to self, buy new lights to replace the ones robbed out of other cab.

Removed the marque.  Vacuumed out the cobwebs.  The light, 18 inch 15watt fluorescent, looked burnt out.  Too late to get one from the store, pick one up tomorrow.  It is pretty dusty, so I cleaned out the dust and wiped it down with a damp paper towel.

I wiped the top panel off with a damp paper towel.  Found a couple pieces of old gum that had been mostly removed.

Both speakers are in rough shape, ripped cones and the rubber surround.  I don't know if they work, but they should probably be replaced.  They were both 6x9s.  The original speaker has only one cone, the second was a three way.

At first I thought the joystick was a replacement, but comparing it to pics on the internet it looks original.

The coin door needs some work.  The coin slots were a bit rusty, and the coin reject buttons were rusty and hard to push.  I removed the coin door to get a good look at everything and send it to the work bench for restoration.

Tip:  As I take screws out, I put them in ziplock bags and label them with a sharpie.  This makes it much easier to remember what screws went where.

[JeepMonkey]

Lew, my pc crashed, so I am running pretty bare-boned right now.  I need to find my photoshop disk so I can resize my pics to post.

Pics to come.

[JeepMonkey]

04/06/04
Work Day 3

I picked up a replacement light for the marque on the way home.  Installed it, but still doesn't work.  I need to find a wiring diagram to help troubleshoot the electrical.

Looking on the net, there appears to be two 2A slow blow fuses, but I can't find them.

I removed the "jamma" plug from the main board.  Wiped down the connectors and the plug, and reconnected.  No difference.

Coin Door Resto Part 1
It was cold outside and no heat in the garage, so I moved into my indoor workbench to get started on the coin door.  A friend of mine who is restoring an old corvette suggested using a fine steel wool to clean the rust off the coin slots and coin reject buttons.  I picked up a pack of 000 and 00 steel wool. 

After taking a bunch of pics I removed the left coin slot.  The steel wool leaves little steel splinters so I put an old towel on top of my workbench.  I started with the 000, and it worked pretty ok.  It was taking the rust off, but it was slow.  The 000 did end up taking off all but one small rust spot, so I moved to the 00.  The 00 took the last bit of rust off pretty fast. 

I know that I could leave the back of the coin slot alone, but it would drive me nuts to know that is was still rusty, much worse than the front.  Since the 000 was slow going, and this was the back, I started with the 00.  The 00 was much faster, but like before there was a rust spot that the 00 couldn't remove.  Again I could have let this go, but I would not let the coin slot get the better of me.  So I close off the work area so my cat wouldn't decide to play in all the parts laying around, and went to Lowes to get some 0 steel wool.  The 0 steel wool made light work of the last spot on the back.

The second coin slot went pretty much the same as the first.  I didn't stick with the 000 as long as the first because the 00 didn't scratch up the first.  Once the front side was done, I started with the 0 on the back.  The 0 steel wool worked great.

The steel wool made a night and day difference in the coin slots.

Next came the reject buttons.  It was my hope to get the barrels completely out, but there is a pin connecting then to the next piece, so cleaned them while connected to the coin mech.  The reject buttons were rougher than the coin slots, so I took the 00 to them.  The 00 did ok, but it was soon evident that the 0 was in order.  After a while the buttons moved smoothly in and out and looked much better.

All in all I am very impressed with how well the coin slots and reject buttons look.

[JeepMonkey]

04/07/04
Work Day 4

I played around a little more with the coin door.  I had to fly out to Pittsburgh for work for two weeks, so I decided to put the coin door back together.  I know that if two weeks went buy, I would forget how to put everything back together.  Likely some more work will be needed to the coin door when I get back, so I left it on the workbench.

[RayB]

Did ya check the interlock switches?

[JeepMonkey]

I know the main power switch on the top works, as well as the back door safety switch.  Are the interlock swithces you are talking about different than these two?

[leapinlew]

Lew, my pc crashed, so I am running pretty bare-boned right now.  I need to find my photoshop disk so I can resize my pics to post.

Pics to come.

Resize them with Picture resizer? It's free.

[JeepMonkey]

Thanks Lew.  A friend of mine told me about this program this afternoon.  I am currently in the process resizing as we speak.  Pics coming soon.

[RayB]

Yes, interlock switch is same thing as the swafety switch.

[JeepMonkey]

04/25/04
Work Day 5

Started by unplugging the marquee light power at the molex connector.  There was 120VAC to ground at the fuse, so I wanted to see if the 120VAC was getting to the light.  Sure enough there was 120VAC across the black/red wire and the blue/gray wire.  I removed the light assembly from the cab to take pics and look at the parts attached to the back.  There is a filter, ballast, and starter.  I’m not sure which of these parts is bad, but it might just be easier to replace all three parts.

Looking at a wiring diagram, and the fuse rating, it appears that the main board requires 7VAC.  The two 7VAC taps off the transformer are only putting out 1.3VAC to ground.  The main board converts the 7VAC into 5VDC.  I doubt that 1.3VAC is enough to turn anything on the main board on.  The two 12VAC taps are putting out a solid 12VAC.  So I am wondering if the transformer is bad.  It sure would be nice to find a way to put 7VAC on the main board just to see if it worked.

I am off to Texas tomorrow, so it looks like another week of not being able to work on my cab.  But I will be in Austin so I might make a stop by twobits store and peek around.

[bfauska]

You should be able to get 7 volts from a PC power supply.  Use the +12 lead on the positive side of your circuit and the +5 lead on the negative side.   Try it with a multi-meter first, but I have heard it works.  Somebody may be able to confirm or deny this, but I know people do it for PC fans to run them quieter.

[leapinlew]

Anyone can say these things. Real men prove it.... with pictures. 

[SirPeale]

Started by unplugging the marquee light power at the molex connector.  There was 120VAC to ground at the fuse, so I wanted to see if the 120VAC was getting to the light.  Sure enough there was 120VAC across the black/red wire and the blue/gray wire.  I removed the light assembly from the cab to take pics and look at the parts attached to the back.  There is a filter, ballast, and starter.  I’m not sure which of these parts is bad, but it might just be easier to replace all three parts.

The easiest (and cheapest) to do is the starter and bulb.  If it's still not working after that, then it has to be the balast.

Or you could just get a new fixture from the hardware store.  $6.00 and you're done.

[JeepMonkey]

Some pics...  Just for Lew

Front


Right side


Left side

[JeepMonkey]

Here are a couple pics of the coin slot "resto"

[JeepMonkey]

Here are a couple more pics of the coin slot "resto"

[JeepMonkey]

bfauska - I am not sure if you can get 7volt out of a pc power supply.  The problem of your theory is that a pc power supply puts out DC voltage, where I need AC voltage.  I do appreciate the thought.

[JeepMonkey]

Peale - I am considering getting the three new parts, but I may try the starter first.  I have considered replacing the entire assembly, but I would like to keep this cab as close to original as possible.

[bfauska]

I don't have any hands-on experience with an arcade boards power, but 7v AC? seriously, that sounds odd, voltages in that range are super rare in any of the electronics I DO have experience with.  I was looking to see if that was the case and I found a site that may help you diagnose your troubles, in particular they have a diagram of using a power supply to replace the transformer.  The site is Two Bits, they do repairs but also seem to offer information as well.  The diagram I am referring to is this at the bottom of this post.  Those coin door came out great, it looks brand new, or at least as good as it did when it was only a few years old.

[bfauska]

OK, so in my continued quest for knowledge about the voltages in your system (which as you know are in fact AC) I came upon this troubleshooting article that sounds as though it could be very useful to you.

 1.2v where there should be 7v you say?...

09/03/2001

Problem: Board works fine in JAMMA adaptor, but dead in a standard AC Pac cab.

Tools: VOM, Soldering iron and solder

The game powered up and played perfectly using a Pac to JAMMA adaptor, but would not power up once it was plugged into the cab. I tested the voltages on the un-banded sides of D7 & D8, this read 15 VAC, then tried the same on the un-banded sides of D3 & D4 reading was 24.56 VAC. Both are fine. Then I checked the DC across the large electrolytic caps C7 & C8, each should read about +5 to +7 VDC. These were fine too. Next step, check the voltage at the Base of the Q6. The reading should be around +7 or so. What? It's +1.23xxx, Hmm. What is going on? After replacing both Q6 and IR1 I still had the same problem. Just for grins I checked the 5 Watt 50 ohm resistor at R52, since it was the only thing left on that section. Open! The resistor was OPEN! Replaced the resistor and tried the board back in the cab. Powered up a played perfectly. I fixed 2 boards this evening with the exact same symptoms and both had bad R52 resistors.

Solution: Replaced R52, a 5 Watt 50 Ohm wire wound resistor.

[SirPeale]

Peale - I am considering getting the three new parts, but I may try the starter first.  I have considered replacing the entire assembly, but I would like to keep this cab as close to original as possible.

It's already been changed.  The original fixture was two 110V AC bulbs, mounted on each side.  If you remove the marquee you'll likely see the mounting holes.

Failing that, how's this: buy the $6.00 fixture and use it for parts.  Comes with a bulb and a ballast.  If you try and source them individually you're gonna pay thru the nose.

Replace BOTH the starter and the bulb, esp. if the bulb has burnt black ends.

[JeepMonkey]

bfauska - Thanks for the link.  I will definatly use that.  I thought is was a little wierd at first, all if the low VAC sources, but they are everywhere in my cab.

Peale - My light assembly looks just like the one in the Parts and Operating Manual.  It shows a single bulb assembly.  I will have to look for other mounting holes when I get back home.

[SirPeale]

Peale - My light assembly looks just like the one in the Parts and Operating Manual.  It shows a single bulb assembly.  I will have to look for other mounting holes when I get back home.

It's also possible that I'm wrong.  It happens occasionally. 

But for spare parts, you can't go wrong with doing what I suggested.  Those cheap under counter units come with everything you need to get your existing unit going again.

[theCoder]

Great find on the cab.  Now that I can see what it looks like    I'm impressed.  Did you get your Photoshop reloaded?  Good luck tracking down your electrical problems. 

[JeepMonkey]

Peale - I will definitely look into your idea.  If I can get the parts from an el cheapo light assembly it is worth looking into.

theCoder  - Thanks.  I have not spent too much time reloading my pc, as it will likely become a MAME machine if I can't get reserect my old drive.

[psychotech]

 

NICE!

Can't say much more as there are not too many legacy cabs available here...

Good luck, whatever you decide to do with it!

[bfauska]

Any progress.  I was looking forward to see if I helped find a fix to your woes.

[Level42]

VERY nice cab, I WILL own a Ms.Pac Man one day..........Congrats !!

Peale, I'm not sure about Ms.Pac Man but Galaxian has tube lighting originaly for the first 3000 built. I never really understood why they changed "back"to normal light bulbs that eat lots of current, but I guess the electricity wasn't that expensive back then..... anyway it COULD be original.

I did the same thing with my Galaxian that Peale suggests, I bought a fixture incl. lamp and just used the parts, as the fixture was too wide anyway (and I had managed to smash the tube that was in it....) works great, check out the Galaxian No.815 thread.

About the 7 VAC. You never measure AC voltages to ground. You need to measure between the two leads to see if there really is 7 VAC.

Yes these old machines used AC and the AC was (is !) converted to DC on the PCB. Check if you have the normal DC voltages (to ground !) on the PCB, like +5V, +12V and maybe -5V and -12V (I'm not 100% sure if there are test points on a Pac PCB. If not, look for the small capacitors near the RAM chips. Usualy these are always connected between ground and 5V, so you can measure over them.

Is there any noise or anything on the screen at all ?

[JeepMonkey]

psychotech - thanks.  Legacy cab?  Not sure what you are meaning here?

bfauska - I am still in Austin, TX, so I have not been able to work on my cab.  But I have been trying to do research.

Level42 - thanks.  I was not exactly looking for a Ms Pac, but it seemed to good a deal to pass up.  Why not read AC to ground?  I do this very often to see if a single point is hot.  Measuring AC voltage from a given point is going to read a difference of potential.  Ground should have zero volts.  So whatever you read on a given point will tell you the voltage at that point.  There is nothing visual on the screen and the only noise is a voltage hum.

[bfauska]

I am still in Austin, TX, so I have not been able to work on my cab.e is a voltage hum.

That seems totally counterproductive, go home and play.  What's more important than play?  Work, Family, Friends? Nah....   OK maybe a little.  I thought I was anxious to find out if it'll work, I couldn't imagine if it were my cab and I were out of town for so long.   Actually I'm out of town for this week and my coin door just got to my house, no I wanna go home. 

Have a good trip and hopefully you can make your Ms. Pac come to life when you return home.

[JeepMonkey]

05/14/07
Work Day 6

Started this work day by going to Lowes to purchase a ballast and starter for the marque light.  I also purchased a nice Klein small wire gauge strippers.  Klien are my personal favorite tools and I am slowly rebuiling my collection again.

Once back in the garage I replaced the starter first since it was the easiest to install.  Plugged in the cab, no light.

Next I installed the new ballast.  Plugged in the cab, and there was LIGHT!

I tried the old starter with the new ballast, and still had light.  Next I tried the old light bulb, no light.

So it turns out the light and bulb were both bas and the starter was good.  I went ahead and left one of the new starters in place, so right now I have a new starter, light, and ballast.

Cost:
Starter (2 pack) $1.98
Ballast $4.88
Light $7.00
10 pack of "bell" style connectors $1.92
Total $13.86

Now I need to clean the marque plexi and replace the speaker so that I can put everything in the marque area back together.  As the speaker does not work, I may wait until I know the speaker works before putting this al back together.

This is a small step, but it is a step forward.

Before


After


Old and new parts

[SirPeale]

If you'd followed my advice you could have saved yourself seven bucks.

[JeepMonkey]

05/15/07
Work Day 7

I decided that I might just send my main baord into a professional for testing.  I removed the main board from the cabinet and cleaned it up. 

Reading on the internet I found multiple sources that say that the RF filter board usually gets discarded as it causes more troubles than it prevents.  With the RF filter board removed from the main board, I decided to try the main board in the cabinet without the RF board.

Success!  The game works!  The game and dip switch setting all seem to work fine.  The color is a little off, the blue ghost is very light and has a shadow, all of the dots have a shadow that actually makes it look like there are two dots, and the score is not a exactly white.

The color situation isn't too terrible, but I may still send the board off to be tested.

Anyone have any suggestions as to what may cause the color problems other than something on the main board?

[theCoder]

Anyone have any suggestions as to what may cause the color problems other than something on the main board?

I'm no expert on this topic, but I've read numerous times that a monitor "cap kit" usually solves many monitor problems.

[JeepMonkey]

05/24/07
Work Day 8

Today I did some research on cap kits and removing/discharging the monitor.  I have a Wells Gardner 19K4906 monitor with a RCA 19VLTP22 tube.  Here are a couple pics of the monitor.


The ghosts are a little off color.  The red ghost looks green and the blue is a bit light.


Ms Pacman has a blue tint to her.  You can also see the dots have a shadow that makes it look like two dots.


The score has shadows and have a red/pink tint

[8way]

You can also see the dots have a shadow that makes it look like two dots.

You can fix that by adjusting the purity rings. Not sure if anything else causes that effect besides the purity rings.

[SirPeale]

What kind of monitors in there?  Looks like your colors are inversed.