LIS had issues during gameplay where all of a sudden the DMD would show the VOLUME LEVEL dropping from 17 to 0, all by itself! Then it added Player 2, then 3 while Player 1 was playing!

I was sure it was the WhiteStar CPU/SOUND board so I swapped it out with a known to be good identical CPU/Sound from my South Park (Identical P/N).

Swapped the (6) ROMs from board to board on the bench, mounted the pulled CPU/SOUND board from SP into LIS, power up..seems ok..set the ADJUSTMENTS; Set for Free Play; Reboot the game;

Comes up and about 3 minutes into play, the same crap!!!! Volume drops from 20 to 0 on the DMD, adds 2nd Player.

Anyone have a clue what the culprit might be here? Frustrating for sure!

THANKS!

EDIT:

I should add that the I put the CPU/SOUND board I pulled from LIS into SP to see what would happen.
Well the sound seems "speeded up" at times and speech out of sync with what I am used to hearing on SP.
Also I get a loud "PFFFT" sound out of the speaker on power up. Game seems to play and score ok but the sounds are not what they were and the speech bites seems like they pop up randomly.

I could do that .. but I am still mystified by why the sound isn't/won't work properly after moving the CPU/SOUND board from LIS to SP. This music speeded up thing is strange..like taking a 33RPM record and playing it 45RPM..like it's trying to catch up.

About 2 weeks ago the LIS sound/speech had quit all together, which is why I pulled the board and re-seated all the SOUND ROMS initially (which did restore the sound/speech at least).

Where did you find a new board? Rottendog doesn't appear to make this one.
BTW, I'm from Baltimore but live in FL now. Arbutus, Catonsville area.

UPDATE: Ok, thought it may have been coin door switches.
But this is for sure. The game will sit turned on just fine. Soon as I drop a ball into the "O" Hole scoop, game resets..

I do believe the CENTER SUPER VUK switch is missing the diode completely. See Pic. Culprit?
If so, is it a IN4001 or 4004?

SUPERVUKSWITCHLIS.jpg

Bump.
Anyone have a pic or a manual to check for diode on switch please. Mine is missing a diode.

One of the symptoms was the game restarted, or the volume would drop, or a player or two would be mysteriously added. I replaced the VOLUME coin door switch which was "sticking"..but still had the issue/ Then I checked the left coin door switch my removing the mech and putting that back together.
Now the stuck switch in ROW6 has vanished. Game is back to normal. We shall see how long cause I'm not 100% sure I fixed it.

No, never lost the 50V as two of the items in ROW6 was the RIGHT SLING KICKER and the BOTTOM LEFT TURBO BUMPER and they fired.

Played the game for over an hour tonight. Everything worked properly.
The part I am still confused about is the loss of sound/music/speech which is now fine, since that short in the matrix seems to be gone.

My LIS issues have stayed away for a few days now with heavy use.

Not 100% sure what I did to fix it, but it seemed to be related to the "sticking" RED VOLUME switch on the coin door. Also tinkered around with the left coin slot switch which was part of the ROW 6 switch matrix.

I had pulled the CPU/SOUND board from the backbox and game it a good look over prior to that.
Pulled all the Speech and Game ROMS , inspected and reseated them, but still had the issues of no sound.speech and no music. Not until I replaced the VOLUME switch on the coin door did things become normal. This RED VOLUME SWITCH is a dedicated switch too.

So on your game, what do you mean by "SEIZED"?

Check the ROW6 Switch Matrix like I did and report back.