Could use some help getting baby pacman to boot

[brad808]

So I have a baby pacman game that I've never had boot up. When I first got the game it had the main fuse blown. I replaced that and tried to start the game, the mpu wouldn't go through the boot sequence (led stuck on). There was a lot of corrosion on the board so I decided just to get a new one. I tried a different mpu and still led stuck on.

I'm looking at the power now and tested the transformer, all tests good. On the rectifier board (as-2518-132) test pins 1 and 2 have no voltage, all others test fine. I could use a couple hints as to where I should be testing and what I should be looking for. I've tested with the connectors both connected and unplugged and still no voltage at those pins. I've tested the fuses and they appear to all be good.

Thanks for any help that can be given.

 

[Grauwulf]

Neither of those two test point voltages are used in Baby-Pac according to that diagram, so it's okay not to have them. If your LED is locked on you need to get the mpu out of the machine and test it on the bench. Where are you located?

 

[brad808]

Neither of those two test point voltages are used in Baby-Pac according to that diagram, so it's okay not to have them. If your LED is locked on you need to get the mpu out of the machine and test it on the bench. Where are you located?

Hmm alright maybe I'm still searching for a problem in the wrong place then. I'm located in Brantford.

Sent from my Nexus 4

 

[Grauwulf]

How are the boards for corrosion? What was the second board out of? Has the second board you tried been jumpered properly for the same size/type eproms that were in your original MPU board? There's a lot of things it could be.

My ex-wife had a Baby-Pac, I know what they are like to work on.

 

[brad808]

How are the boards for corrosion? What was the second board out of? Has the second board you tried been jumpered properly for the same size/type eproms that were in your original MPU board? There's a lot of things it could be.

My ex-wife had a Baby-Pac, I know what they are like to work on.

The first board (that came with it) had a fair amount of corrosion, which is why I suspected it was bad and bought the second one (which is supposed to be working). The second one has no corrosion. The second board was from kings of steel. I removed to resistor and replaced it with a diode to convert it from a - 35 mpu and I basically matched the jumpers from the original MPU board in hopes that it would work. I should note that when I first got the board I installed it on the game (just j4 power hooked up) without changing roms or anything and the led was locked on. That's the reason I suspected bad power. I've since swapped the roms and changed the jumpers (I think correctly).

Sent from my Nexus 4

 

[sylvain]

Before doing any work on the MPU,
Make sure the MPU itself is getting +5.0 volts from the power supply.

Cheers,
- Sylvain.

 

[brad808]

OK so I've hooked it all back up and checked the test pins on the mpu.

TP1 - 1.65 Volts (Should be 5)
TP2 - 16.6 Volts (Should be 11.9)
TP3 - 4.95 Volts (Should be 21.5)
TP4 - Ground
TP5 - 1.65 Volts (Should be 5)

I then checked connector J4 which is the power going into the mpu, pins 16 and 17 should be +5 and they are at 1.41. So I'm guessing a problem between the rectifier board and the mpu maybe?

PS Grauwulf, I've actually met you before a few years ago you came down and bought an arkanoid from me.

 

[sylvain]

I would double check that the Solenoid Driver indeed outputs +5V again first.

If the MPU has corrosion, the old battery might also have damaged connectors including female pins inside J4 on the MPU.
Confirm if +5V arrives on J4 wires pins 16 & 17 from the top of the connector. If yes, then replace the bad Molex 0.100 pins.

You can also use a flashlight to look at the pins inside J4 - pins could be bent or broken. Very typical of corrosion.
You might need to repin other connectors if indeed corrosion got to them.

Good luck !
- Sylvain.

 

[brad808]

I would double check that the Solenoid Driver indeed outputs +5V again first.

If the MPU has corrosion, the old battery might also have damaged connectors including female pins inside J4 on the MPU.
Confirm if +5V arrives on J4 wires pins 16 & 17 from the top of the connector. If yes, then replace the bad Molex 0.100 pins.

You can also use a flashlight to look at the pins inside J4 - pins could be bent or broken. Very typical of corrosion.
You might need to repin other connectors if indeed corrosion got to them.

Good luck !
- Sylvain.

I think I'm getting closer, it appears j4 on the mpu pulls power from j8 on board a3 (voltage regulator, solenoid driver board). All test pins in that board are also reading low (1.7 volts or so) but should be at 5v. Hmm I get deeper down the tunnel...

Sent from my Nexus 4

 

[Grauwulf]

PS Grauwulf, I've actually met you before a few years ago you came down and bought an arkanoid from me.

That was the one in the Kangaroo cab, right? It's guts are still living happily in the machine I built for my gf.

 

[brad808]

PS Grauwulf, I've actually met you before a few years ago you came down and bought an arkanoid from me.

That was the one in the Kangaroo cab, right? It's guts are still living happily in the machine I built for my gf.

Yep you got it.


I'm getting 16 volts at TP1 on the Solenoid Driver board. 1.6v at TP2. It seems as though it should be changing from 16v to 5v at q41 voltage regulator (with the huge heatsink) as far as I can see on the schematics. Tp1 is the voltage going into the regulator and tp2 is the voltage coming out (and also where the mpu gets its 5v from). Does my testing seem right? What should I be testing/replacing q41 with?

Sent from my Nexus 4

 

[brad808]

So I tested the new mpu on the bench this morning and it seems to pass the self test.

I'll be heading down to Sayal this morning to see if i can find replacement parts for q41 and c2 on the Solenoid Driver board to get the 5v line working again.

Sent from my Nexus 4

 

[Menace]

Before you head down to Sayal, use their website and search for the parts you need. It's pretty good and gives you the locations that have stock and how many. (and if it's on the floor or in the warehouse, which then means you're going to have to buy $15 per item of those)

D

 

[brad808]

Before you head down to Sayal, use their website and search for the parts you need. It's pretty good and gives you the locations that have stock and how many. (and if it's on the floor or in the warehouse, which then means you're going to have to buy $15 per item of those)

D

Thanks menace. I actually went on Saturday morning to the one in Burlington and was able to get the voltage regulator that I needed. They didn't carry caps that large so I'll probably order one online because the store is about 45 minute drive for me.

Anyways I got the voltage regulator installed and I have my 5v working correctly. MPU passes self test now in the game.

Vidiot board however has problems... Sort of expected it though so I'm not too surprised. It's self test claims a problem with u10 ROM. I'm guessing (hoping) the socket just needs to be replaced because finding the ROM seems like it will be difficult. The back of u10 socket looks like it got a bit of acid damage so once I replace that and it still doesn't work then I'll panic haha.

Sent from my Nexus 4

 

[Menace]

If it's just a ROM, contact Dave Astill or Steph @ Hobby Rom's out in Ottawa.

D

 

[Grauwulf]

Were you able to breathe life back in to your Vidiot board? Enquiring minds want to know!

 

[brad808]

Were you able to breathe life back in to your Vidiot board? Enquiring minds want to know!

I was able to. Redoing the sockets cleared up the vidiot. I lose track of what I've posted and what I haven't haha. I got the game working and got to play it a bit. There was a problem with the right flipper shorting though. I was procrastinating on it. Fast forward a couple weeks (or months) and I found another game I wanted, couldn't reach an agreement on price with the seller but was able to work out a trade deal so on last Friday we made a swap and now I no longer have baby pacman.

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[Grauwulf]

Aww, bummer. What did you take in trade?

 

[brad808]

Aww, bummer. What did you take in trade?

Revenge from Mars. It was baby pac + cash for the rfm. So even though I lost a video game pinball hybrid I at least gained a video game pinball hybrid ;-)


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[Grauwulf]

Oh Nice! This wasn't the one that the guys couldn't get to boot was it? How's the PF on it?
I'd rather have RFM over Baby Pac any day of the week.