MPU or Sound Board?

[Fifty]

Hi guys,

I've posted this over on MAACA and on Pinside, but I wanted to post here as well with the hopes of someone here possible being familiar with this problem.

My White Water is playing music at random. Sometimes in game, sometimes while just sitting in attract mode. Sometimes the pin will sit silently in attract mode for 5 minutes before the music will start playing. Sometimes it will sit silently for 45+ minutes. Please note: I have attract sounds off (factory default).

I thought it might be the sound board. I replaced the EPROMs first (easiest, cheapest) but the problem remained. I disconnected the ribbon cable and reconnected it. No change. Then things got really interesting, I borrowed another sound board and replace it entirely. This time the music started to play instantly in attract mode. I reseated all the ribbon connections and same thing. The music started to play almost instantly every time with the borrowed sound board.

So I disconnected the ribbon cable from the sound board. This time the pin just sat there for hours and the music never played. This leads me to believe the sound board is fine and that the MPU is triggering the sounds incorrectly. So I moved my focus to the MPU.

The MPU is an aftermarket Rottendog board. No visible damage to it. At this point Pinhead over on MAACA has offered his Creech to install the MPU into and see if the problem migrates to his pin. If it does, then I know there is something funky going on with my MPU. If it doesn't then I'm in the same shape I am now.

It would probably be best to try another MPU in my White Water but until that happens is there anything else I can try?

It's an odd issue and there is no information on how sound is triggered off the MPU to the sound board that I've been able to find.

 

[Menace]

The issue is absolutely with your MPU given your description. Have you tried swapping ribbon cables completely? Have you tried reseating the ASIC chip? I would start there as those are easy to do, but you will need a PLCC chip removal tool for the ASIC.

Failing that I would have to look at the schematics and then using a locgic probe monitor the sound enable line from the MPU and working your way back from the ribbon cable connector towards the ASIC and see if you can find where the data is being corrupted. (It would be great if you had a working MPU you could use as a reference)

D

 

[Fifty]

I received my new IC's from Digikey on Thursday. Saturday night I dedicated some time to fixing this. Based on the info from Pinball Rehab I decided that U1 was the most logical culprit. The problem was associated with J202, so it had to be U1 or U3 that was the problem. Since U3 was bidirectional, I made an educated guess and decided to replace U1.

I desoldered the existing LS244 from the PCB. I added a socket and carefully pressed a new LS244 into it. Then I re-installed the CPU into the backbox, connected everything up and turned on the game. I decided to play a game right away. The problem I was having with the music was getting worse and it was happening more often during gameplay. I pressed START and put up a decent score. No music issue.

Today I decided to finish up working on Champion Pub. So I would be in the same room with my White Water for most of the day. I turned on White Water and left it on pretty much the entire day. At least 4-5 hours. No music issue.

U1 was giving me my problems. It's funny, and this goes back to what Sylvain was saying in another post, new components can cause as many headaches as old ones. This pin is from 1993. The CPU is a brand new Rottendog replacement probably from 2010 or possible even later. The component that failed was on a new CPU.

Needless to say I'm stoked! It's not possible to get a larger smile on my face.

 

[Menace]

Glad you got it sorted out, and thanks for posting the results here for future reference!

D

 

[Fifty]

Thank you for posting and trying to help!

I make it a point to always update my troubleshooting posts. You never know when someone else might have the same problem. If my post is open then it means I still investigating.