Just found this thread today. Hoping some of you are still around to clarify what may be wrong in this setup that I have. I have a Laser War with a version 3 mpu in it. The game is fully playable. All sounds, lights, and solenoids are working properly and playing it is a blast.

There is nothing displayed on any of the displays though.

I just rebuilt the HV section on the power supply and have proper voltage on the power supply at connector cn5 for the displays, and on all 5 of the connector pins (pin 2 and 12) for each of the displays attach to it. 3 of the displays (player 3,4, and the ball/credit display) were tested in my Black Knight and all work great. I cannot test the 2 DE displays for player 1 and 2, but have tried with them plugged in and unplugged with no difference. I have the extra pins added at cn3 on the mpu for the ball/credit display as well.

There is no chip at B5.
What looks to be the original Laser War game rom chip with original factory lable is installed at C5.
There is a 6264 installed at D5.

Do I need to burn a different game rom chip to work with the 6264, or can I just swap it out for a 6116 as per the original version 1 mpu?

Someone was messing around with the jumpers on this board for some reason and had a couple of them crossed j4/5 each had one end of a jumper attached on each one, as did j7a/b. J6b was installed but not j5b.

I don't know if that would damage anything or just send game information or partial information to the correct/wrong place.

Currently I have the jumpers installed as follows:
J1B, J3, J5, J5A, J6A, J7A, J8.

The following are NOT installed:
J1A, J2, J4, J5B, J6B, J7B

With the original game rom at C5, is having J5 and J7A installed correct?

Will that original game rom work correctly with the 6264 installed at D5 or do I need to install a 6116?

I don't know what the original game rom is as far as what type of chip. Do I need to burn a new game rom on a different chip to have it work with the 6264 currently installed?

Just trying to clear up some confusion on this board and hopefully that will get the displays to display information!
If not, then I suppose I need to look into something else on the mpu maybe not putting out signals to the displays? I would think everything should be good through the PIA though since the power up lights are correct every time.....

Thanks in advance!

Have a 27256 at 5C. Changed jumper j5 to j4. still no displays.

OK. I did a search for Laser War game rom. The original Laser War board had 2 chips one at B5 and one at C5. B5 was a 27512 or 27256 and C5 was a 27256. Since there is only one chip on this board, the 27256, I'm assuming that the other chip is missing. I see K's Arcade has a new 27512 that would replace the pair of chips. I'm thinking there is information missing from the missing chip and it must have to do with the displays.

I'm going to order the new single rom game chip, remove jumper J4 and install jumper J5 and see if this resolves the issue of all the displays not displaying any information. Obviously, when someone put this version 3 board in here, they didn't know what they were doing anyway since all of the jumpers had been messed with and several were crossed between 2 jumpers. Maybe they got rid of a chip that needs to be there too, since there should be 2 chips if your using a 27256 at C5 instead of a 27512 with all of the game info on it. Ugh.........

I will update in a few days when the new chip arrives.......

Installed the new 27512, game plays, but there is STILL nothing on the displays.

After poking around with a probe, testing voltages at all the chips on the display driver board, and trying to think some more, I compared RA1 ,RA2, and RA3. RA2 and RA3 control digit strobes, according to the schematic, and RA1 controls numerical segment drives. RA2 and RA3 gave the same readings for each and RA1 gave no readings at all. So, how can anything be shown on the displays if the segments aren't being driven? Probably can't..... right?

The schematic says RA1 is a 18Kx9 resistor array. Is there any other information or specs I need to know to get the proper one to replace this with? Mouser sure comes up with a lot of results and options.......

Any +/- on if this could possibly be the issue?

UGH!

I just put the MPU from Laser War in my Monday Night Football. The MPU is putting out the display signals just fine because it came right up on the display with data east presents laser war........ MPU VERIFIED GOOD. DONE.

It's got to be somewhere on the display driver board.

There is activity on all 3 of the display connectors on the mpu at cn1 cn2 and cn3, and the ribbon cable on cn22.

There is even activity on all of the player display connections on the display driver board AND voltage at the same connectors for each display.

Something is keeping them all from actually lighting up and displaying the information.

I don't think it is the RA that I mentioned above anymore. I noticed that the other 2 RAs have +5 to pin1 and this one has ground to pin1, so they should be measured in reverse (switch black and red leads from meter) and they read the same reading as the other to RAs. correct?

I've even removed the ribbon cables with the displays and tested player 3, 4, and the ball credit in my black knight, all of them work just fine. Ive swapped the main ribbon cable from cn22 on the mpu to the driver board with the one from monday night football, and no change. the ribbon cable works just fine in the monday night football too. no cable problems, no voltage problems, and the displays work in other games.

MPU verified good output for displays in MNF.
Ribbon cables all verified good in black knight.
player 3, 4, ball/credit displays all verified good in black knight.
all 3 voltages present on display driver board.
all ics have proper voltage at voltage pin for each chip
all voltages present at all display connectors (1,2,3,4, and ball/credit)
activity at all display connectors with logic probe

why won't they just light up?!!?

This was just mentioned to me in another thread.

>>>>Here is a test for two of the chips! Do this w everything off! http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#Display_Panel_Problems<<<<<;

Perfect. I removed the board and tested the UDN7180/UDN6116 on the display driver board. The 3 7180's tested good. All 4 of the 6118's tested bad. Looks like I've got some sockets to install on this board

How can I test the 4050BE and 4001BE? There are 4 of each on this particular board.

OK, so I just tested the 4050's with the board removed from the game. Had one lead on ground and other lead probing each leg of each chip. All 4 of the chips gave the same readings on each leg, meaning pin 1 of all gave the same, pin 2 of all gave the same, ect. when each of the same pin was compared to the reading of the same pin on the other chips. Is this the correct way to test those? I have a digital meter so I can't see any "bounce" as mentioned in the old pin repair guides.

Some progress today! UDN6118s arrived in the mail and were installed with new sockets on the display driver board. We now have some digits that light up, but most are still out.

Player 2 and 4 have both the ten thousand and hundred thousand digits light up. The 1st of the 2 digits in the balls display and the first of the 2 digits in the credits display light up. I can now see when I'm in the display test and the digits that light up work for all numbers.

Now, what's next to figure out what's not lighting up the other digits?

How can I test the 4050be and 4001be?

Few more updates:

Looks like the 4001's control the digits, and the 7180's and 4050's control the segments. I ordered some of each, but I'll be replacing all 4 of the 4001's next and putting them in sockets as well.

Something did a doozy on this display board.

Also was able to finally verify that player 1 and 2 glass displays are good.

Update again in a few days.

IMG_0554 (resized).JPG

Excellent.

FINALLY, we have full operation of all displays! I replaced all 4 of the 4001's on the display driver board and everything is now up and running 100%. Wow. New transformer, rebuilt HV on power supply, proper jumpers, new C5 rom, replace and socket all 4 UDN6118's on display driver board, replace and socket all 4 4001's on display driver board, and we finally have full display operation.

That's got to be the most extensive display operation project ever.

Thanks for everyone's patience, help, and suggestions along the way. It is much appreciated!

Now, it's game time.