How does the MPU trigger sound or music on a WPC sound board? I'm having issues with my White Water. One piece of music is randomly triggering. It triggers in attract mode even with attract sounds turned off. It triggers randomly during play. Each time it's the same piece of music.

I went into Test Mode. Under Sounds + Music the piece of music I'm looking for is not listed. Actually, quite a few sounds and music are missing. The music I'm looking for is the LAST CHANCE music for the WHIRLPOOL CHALLENGE. Is it not possible to test all the different sounds and music using Test Mode???

So this has led me to the MPU triggering music on the sound board. What on the MPU triggers the sounds? I guess I'm trying to figure out the signal flow so that I can find whatever is causing the music to play whenever it feels like it.

(I have another thread going describing this same issue, but it is no longer relevant and I'm going to close it.)

I'm going to try to isolate the problem first. I will borrow a spare sound board and swap mine out for it. If the problem remains then I can rule out the sound board and assume it's the sound EPROMs, ribbon cable, or MPU causing issues.

It would be nice if I could do a 1 for 1 swap using someone else's WH2O and chipset, but I don't know how much luck I'll have with borrowing one.

I'll see what I can do. It's difficult to ask someone to rip there perfectly good pin apart to help me troubleshoot.

I wasn't able to borrow a sound board. I ended up buying a new set of sound roms and installed them tonight. I figured this was the cheapest option and easiest thing to check. I had the pin on for about 45 minutes and the problem returned. So the problem is on the soundboard or MPU.

I'm still looking for another sound board to isolate the problem but it looks like I'll start going through MOT's recommendations and get some 74LS374 replacements.

Thanks SOKOL. I'll try this.

I have soldering experience + and new Hakko.

I'm trying to source a sound board still. Pinsiders in Ottawa are many, but borrow an audio board has been difficult.

My replacement 74LS374 ICs showed up today so I decided to removed the WPC sound board and solder them in. I removed the ribbon cabling, and the Molex connectors then loosened the screws so that I could remove the board. Then I saw this;

Do you see it?

See it? Look closely, here's a better photo;

There it is!

The capacitor right by the transistors blew. Not just a bit, but entirely. I removed the cap off the board and it crumbled away like a caterpillar than has been fried by a magnifying glass. I cleaned up the board as best as I could. Luckily all the traces are on the underside.

I think it's C36, but the label is scorched off. I'll check the manual and order a replacement tomorrow. For now, I'm putting a hold on installing the 74LS374 chips.

[EDIT] Looks like it's actually C26. This is the part that I need;
http://www.marcospecialties.com/control/keywordsearch?SEARCH_STRING=5041-09031-00

Off to Digikey to see what they have.

I did see that it was listed as TANT in the manual. When I typed in the Williams part number (5041-09031-00) into the search on Marco this is what came up. It even shows the Williams part number on the webpage.

Either way, I'm not going to order from Marco. As great as they are, Marco's shipping is ridiculous to Canada plus our dollar sucks again compared to the USD. I'll order local from Digikey. This is the one I plan on ordering;

https://www.digikey.ca/product-search/en?keywords=718-1447-1-ND

Thanks for the heads up on the part Chris!

I replaced the TANT capacitor tonight. Put the circuit board back in the game. Fired it up. 5 minutes later the music started playing. Looks like I'm back to the drawing board and back to replacing the 74LS374 ICs.

It's not stupid. Originally I thought it might be this. However, the music will just start up randomly. The game is in attract mode with attract sounds off. The music will just start playing randomly. Sometimes it happens right away, sometimes it takes 45+ minutes to happen. In happens in game as well. When it happens in game, if I lock a ball or something similar the proper music and sounds will start playing again and the 'error' never repeats. Basically it does it once, then it doesn't do it again.

Ideally I would like to swap out the sound board with a working one and narrow down the problem but I haven't been able to borrow one yet.

Sweet! I'll definitely do this.

FYI... I decided to remove the ribbon connector from J506 (on the sound board) and turn on the game. My theory is two fold;

1) The sound card is malfunctioning.

or

2) The MPU is triggering the sound card when it shouldn't be.

Therefore...

a) If the music starts playing with J506 disconnected then the issue is on the sound board. Why? The data all flows through the data ribbon cable but the cable is disconnected. The speakers are connected directly to the sound board so if music starts playing it means the sound board is the culprit as it cannot be triggered through the data ribbon cable.

b) If music doesn't play... well then my theory is shit, or something is triggering the music from the MPU when it shouldn't be.

So just an update...

With J506 removed the music never plays. So this means there is something triggering the music to play off the MPU.

Since dr_nybble was kind enough to offer me his sound board I went out and picked it up today. I installed it and something I didn't expect to happen ended up happening. The problem got worse. I turned on the pin, it did it's quick boot up procedure and the music started to play instantly. I turned off the pin. I turned it back on and the music started up instantly again. WTF?

So I put the original board back in and turned the pin on. No music.

To me, this means the problem isn't on the sound board. Why would it get worse with the borrowed sound board installed?

Needless to say I am confused.

I need to revive this thread. Surely there are a few people on here that have the wisdom that I don't and that are able to help with this.

First off, SOKOL suggested leaving the pin on for 45 minutes and then touching U2, and U3 to see if they were hot. They were not. Neither were any of the other IC’s on the MPU

Summary
- Installing another sound board made the problem worse.
- If I disconnect J506 from the sound board the problem does not occur.

I am going to assume the sound board is not at fault here and that the MPU is sending an incorrect signal and triggering the sound board to play music at the wrong time.

So my focus will be the MPU. Before I begin digging there is one thing I want everyone to be aware of. This is not the original factory board. It is a Rottendog WPC089-TH replacement. Rottendog replacement boards were created using the Williams schematics so they are a drop in replacement. There are no visual signs of damage on the board. Okay, now that that is out of the way...

If I follow the ribbon cable from J506 to the MPU it connects to J202. J202 is a 34 pin connector. All of the EVEN pins are GND with the exception of 32 which is N/C and 34 which I believe is VCC.

J202 odd pins 1-15 are pulled up by a 4.7K SIP and then connect to U3.

STEP 1:
I will measure the SIP and confirm all the EVEN pins on J202 on are properly grounded.

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 a post of friend of mine put up, but he was saying in another post that new components can cause just 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.

Sure does! This was the most difficult one I've had to troubleshoot to date.

Sweet! That was you? Awesome! If it wasn't for your article I'm sure I would still be trying to solve this. Thank you very much for posting this info! I have Pinball Rehab bookmarked now. It really has a lot more depth that other sites I find lack.

I think it would be a decent bet, but you still need to narrow things down to be sure. Is it only the 5x the fun sound effect that is repeating? Is the problem occuring only during gameplay or does it also happen in attract mode?