Skeeball model S ball count issue

[tec9]

That seems somewhat odd....
Try unplugging the switch inputs connector from PCB (J9)
I would then jump pins 2 and 5 to coin it up.
Then jump pins 3 and 4 on J9- this should add up score- but if your display isn't working you won't be able to see the point value change.

If you do have a PCB problem- check U9 I/O, it is a common failed IC.

 

[SuperGunGuru]

Thanks again everyone for your replies. I'll check out what tec9 suggested...hopefully after work. When taking the cpu apart last time there was cold solder on some of the header pins on the far left side. Those were touched up in addition to removing a hack where wires had been soldered right to the pins. I should have looked at the other header pins for switch inputs, etc but oh well it's not too hard to pull the board out again. Also I believe I tried swapping U9 from another (dead) model S CPU and it didn't make a difference. I'll make sure that was the one that was tried.

 

[tec9]

I've got most of the IC's for that PCB if you need some.

-Mark

 

[SuperGunGuru]

I've got most of the IC's for that PCB if you need some.

-Mark

Thanks. That would be much appreciated if it comes to that.

 

[SuperGunGuru]

Ok I tried jumping the pins of J9 directly....got it to coin up and release balls but still no score counting...same as before. Now something interesting to note is that I've had a second spare CPU that came from a Chuck E Cheese location that scrapped several old machines. After swapping components including the program eprom we found out that program eprom from the CEC cpu was causing both boards to not boot...possibly because it was from a "Jackpot" version of skee ball. Now with my original rom in that CEC cpu it will power up with 880 on the display and 8 on the ball count just like the other cpu. This one however has a problem with low 5 volt when a coin/token is inserted. I can watch the voltage drop 1/2 volt with my meter and the game resets. So I'm wondering if this original eprom which allows both boards to function (albeit one with a power issue) is somehow corrupt and giving the 880 on the display. I do have a eprom burner that will hopefully be in soon so if it comes down to it and I can find a copy of the rom online I can verify if mine is okay or not. If anyone knows where I can find the file or can send it to me that would be much appreciated. On the plus side we did get the display boards cleaned up with fixing some traces so now we're at least set there. Thanks everyone for your help.

 

[tec9]

On the PCB that is resetting on coin-op- Check the 14 1N914 diodes - One of them could be bad (shorted)
-Mark

 

[SuperGunGuru]

On the PCB that is resetting on coin-op- Check the 14 1N914 diodes - One of them could be bad (shorted)
-Mark

Thanks again for your all your replies. I'll take a look at the diodes hopefully tonight or some time this weekend. Any thoughts on what the 880 display is indicating? Am I chasing my tail by thinking the eprom could be the problem? I mean I saw that the Jackpot CPU's eprom caused both of the CPU's to lock up and the other eprom lets both boards boot but with 880 on the display. At least there's finally some progress.

 

[SuperGunGuru]

Rather than hijack jachappy's recent thread, I thought I'd bump my own. So I can get my skeeball machine to seemingly count the balls now judging by the fact it will make sounds if I trip the wires, but my display never changes from 880 and neither does my ball count. I'm pretty sure I have my ball trough connected properly....it's hooked up to the 2 pin connector that has 2 red and 2 black wires in each pin. The other two 2 pin connectors only have 1 red and 1 black wire and I'm assuming those are for the 100 point pockets which my machine doesn't have anyway. Can anyone confirm that 2 pin connector with 4 wires in it is where my trough should hook up? Also any thoughts on why the display may not change from 880?

 

[greghig]

Need ID for U9, Skeeball Model S

Adding to this thread as it is Model S Related

Skeeball has wiped out all identifying marks on all the chips making it impossible to replace. Through the process of swapping chips with a known good machine, I need to replace the chip marked as "U9". Schematics just say "I/O". Does anybody know what chip this is so I can replace it? Even better, does anybody have a list of all the chip numbers?

 

[musicman282]

Adding to this thread as it is Model S Related

Skeeball has wiped out all identifying marks on all the chips making it impossible to replace. Through the process of swapping chips with a known good machine, I need to replace the chip marked as "U9". Schematics just say "I/O". Does anybody know what chip this is so I can replace it? Even better, does anybody have a list of all the chip numbers?

So it appears to be a PIA chip which would make sense. The 6821 is what is commonly used for pinball but this doesn't appear to have the pinouts matched. http://sowerbutts.com/replica1-serial/6821.pdf

Probably another brand or model of PIA.

 

[zx6r1996]

Skee Ball Chip U9

Not sure if anybody else ever figured this out, but this is the thread that I kept coming across when trying to determine what I/O chip U9 was on a Skee Ball Model S... So I figured I would post a reply here to help someone else out down the road.

I was working on mine today and figured out what it is. It's an Intel 8255 (also available from other manufacturers such as AMD and NEC).

-Aaron