Baby Pacman Restoration

[CharlieFar]

That looks really nice.
Pinball is not really my thing, but I used to enjoy playing this bitd ('86-'87) in Accrington during my college years.

Are there many other pinball/video hybrid games?

 

[Purity]

That looks really nice.
Pinball is not really my thing, but I used to enjoy playing this bitd ('86-'87) in Accrington during my college years.

Are there many other pinball/video hybrid games?

Granny and the Gators is the only other one I know about

 

[big10p]

Looks lush

 

[Purity]

It's testing time! It's testing time!

So being the cautious man that I am I'm not going to just fire this up and cross my fingers It's all about baby steps. Get it ?

So to start with I checked all the fuses to see if they were correct. Only F3 was wrong. It had a 7A instead of a 6A

Next i fired up the power supply with nothing connected and I got a buzzing from the transformer - a good sign, and an indication I can start to plug things in

But before that I took a reading of the voltage going to the monitor and marquee light. It is meant to be 120v AC and I was 137v AC.

I connected the transformer to J6 on the rectifer board and the input on J5 and put the meter on the test points on the rectifier

TP4 - 6.5v AC - getting 6.9v AC
TP2 - 230v DC unreg- getting 0
TP5 - 43v DC - getting 47.6v DC
TP1 - 6.5v DC - getting 0
TP3 - 11.9v DC unreg- getting 13.6v DC

I think I may have missed something looking at the power supply schematic. TP2 and TP1 don't seem to have any colour coded connectors. They are just labelled 2,3 and 1,4,2,5. Hmmmmm

Anyway back to the monitor and light power. I decided that 137v AC with no load was a reasonable measurement so decided to plug the marquee light in. Fired up and all working. Considering this was hacked up I'm very pleased with that as it is back to how it was originally.

Next I decided to fire up the monitor. I could hear static on power up so a good sign, but nothing on screen, so I turned up the screen pot and can now just see a red square filling the entire screen. Don't know if this is an issue with the monitor yet, as no signal was going into it

Purity2015-09-08 17:10:13

 

[Alpha1]

Is it an Electrohome monitor? G07s show a red screen when there's no signal IIRC

 

[Purity]

It is a WG K4800. It could well be ok. Time will tell when I stick a signal through it

Made a slight school boy error before with TP2, and TP1. If I look at where this goes it says N/U for both of them, I would assume meaning "Not used"

Because these MPU boards are generic and are used in pins I think this voltage is used for scoreboards, and feature lamps etc, which Baby Pacman does not have. So rectifier looks in good shape.

What to plug in next

Also I'm sorry to disappoint Nad because he was hoping to see some sparks and flames

Purity2015-09-08 22:01:44

 

[Purity]

I've fired up the cabinet tonight with all boards connected. Probably a bad idea, but the boards rely on each other for power and communication, so it seems to be difficult to test them individually

MPU seems to be working ok, as I'm getting 6 flashes on the board, which means it is passing its diagnostics, and detecting the solenoid. However I did notice that the MPU seemed to have some higher voltages than I was expecting, which I'm not happy about

Playfield seems to light up, but I was getting a shaking red screen on the monitor.

I think this is because the vidiot board seems to have a fault from what I can see. I am getting the correct 10 diagnostic flashes on that board, and the baby pacman theme, but the board is looping/resetting so the 10 flashes are continuous with the theme playing. However when I press the sound test that seems to be working ok, and then continuing with the looping

I will probably need to put the Vidiot board on the bench to see if I get the same behaviour when I power up from a test harness

I also noticed that there was a smell coming from the lamp/solenoid board, so need to see if that is burnt anywhere

Plenty more work to do :-(
Purity2015-09-08 22:02:58

 

[Equites]

I also noticed that there was a smell coming from the lamp/solenoid board, so need to see if that is burnt anywhere

Sparks and flames??

 

[Purity]

I also noticed that there was a smell coming from the lamp/solenoid board, so need to see if that is burnt anywhere

Sparks and flames??

No sparks or flames sadly

 

[Equites]

I also noticed that there was a smell coming from the lamp/solenoid board, so need to see if that is burnt anywhere

Sparks and flames??

No sparks or flames sadly

Sheesh.Equites2015-09-08 22:19:35

 

[Purity]

Hooked the Vidiot board to my Jamma switcher, and I'm getting the same, so at least it is consistent!

I'm fairly certain that after 10 flashes it is meant to stop - i.e. board initialised

I *think* I have have another Vidiot PCB somehwere so now I've got this setup I may aswell dig it out and see if that one works

Purity2015-09-08 23:13:20

 

[Purity]

I *think* I understand what is happening. It looks like it is failing at diagnostic check 7 or 8 and then just looping the flashes, so 2114 ram failure at U13/14 or a failed [size="-1"]PIA chip (6821) at U7[/size]

 

[Purity]

No joy with this so far.

The only way I can stop the constant flashes is if I remove the rom from
U12. Then I only get the initial two flashes as expected.

I have read the rom at U12 and that idents ok. I have also replaced the
socket but still no joy. As soon as U12 is back in I just get the
looping flashes/sound

I found the other PCB that I had but it is too corroded to use

 

[Equites]

Did you check the PIA and RAMs?

 

[Purity]

Yes 2114 rams are fine. Swapped the pia with the one off the corroded board and it does the same

 

[Purity]

What's interesting is if I remove the rom at U11 it is meant to do a checksum on this for the 4th flash but it is already constantly flashing at this point, and if I remove U12 it stops after two flashes which is correct, which indicates that the problem is on the 3rd flash, which is where the 6809 CPU at U8 attempts to test the program EPROM at U12.

Which then makes me wonder if there is an issue with the 6809 CPU or the socket?
Purity2015-09-09 15:48:58

 

[Purity]

Bit of an update. Whilst probing around the 6809, which was looking fine, the game was no longer continously flashing. It now does only two flashes. So whatever was failing has now failed, and it is stopping at the 3rd flash as thought.

So far I have checked

2114 ram @ U13-U14 ok
Roms @ U9-U12 ok
Sound Rom @ U29 ok
PIA 6821 @ U7 ok
MC4517 ram @ U19-U26 ok

 

[Purity]

A minor step forward today. The vidiot PCB is now working. Problem seemed to be a faulty 6809 CPU but still lots of issues to solve.

And finally some smoke today! One of the solenoids was smoking on the playfield. I think it was the lamp maze saucer but I could be wrong. So another thing to look at.

Getting some monitor issues which I really need to resolve so I can test some other elements of the game

Purity2015-09-10 18:09:50

 

[Vamino]

Man, you are so close now!

 

[Purity]

Testing the Vidiot separately has not really helped. If anything it has confused me more:

I've realised that the Wells Gardner K4800 in the Baby Pac is a medium res monitor because it is the 13" version of the K4900 which is medium res, so this might explain why I'm getting such a poor display on my 1084S monitor?

Looking at the pins it uses on the monitor I can see it is obviously using RGB, and ground. What's weird is that in the manual it says that if you want to use composite sync you use the horizontal sync inputs, but what I can see is the sync connected to both the negative H sync and V sync using the same wire, and this is as configured in the factory connectors? Here's how it is:

I'm also wondering if the capkit I've installed has altered where the pots on the monitor are correct.

These are the options I can see:

I'll post a monitor help thread in the tech section and see what people think

It could well be that I have video issues with the monitor and the vidiot board.

Purity2015-09-10 23:35:30