Bought 3 dotmations, starting from scratch...

[rokgpsman]

It's an interesting idea to replace the dot matrix display on the Williams dotmation machines with another type of display such as an LED or LCD. Over time I've read comments from others wondering the same thing but don't know of anyone that actually has done it. There may have been some similar efforts on this in the pinball hobby due to the large number of pinball games that use a similar DM screen. If you follow up on this we'd all benefit from what you find out.

I'm not exactly sure which parts you swapped during the troubleshooting on the JSD, whether it was only the DM display screen or the entire dotmation display box from the Perfect Match. Is it possible something other than the DM screen is causing the continuous Dot Fail error? (dot controller board, cable from dot control board to backplane, cable from dot control board to DM screen, 12v power)

From my limited knowledge it looks like the dot controller board (left side board inside the dot matrix metal box) sends graphical control data to the back of the dot matrix screen over the narrow ribbon cable that runs between them. The back of the dot matrix screen has its own circuit board that then takes that data and turns on or off the selected pixels on the DM screen which are aligned in a 192x64 column & row matrix.

I'd think that the circuit board on the back of the dot matrix screen also has to produce the higher voltage that the dot matrix screen uses, which is typically around 180vdc or a little higher for gas discharge and plasma gas displays. It is similar to fluorescent lamps, takes a high voltage to cause the gas to ionize and allow electron flow which causes the light to be produced. The only power that board gets from the machine is 12v so my guess is the board has a circuit to make the 180-200v. I've not seen a schematic drawing for the circuit board on the back of the DM screen, although there are drawings for all the other Williams boards in the dotmation slot machine. So that board may be a 3rd party board made by the same company that produced the DM screen and the assembly was sold as one piece to Williams. Williams probably did not treat it as a repairable item, hence no schematic drawings.

So Williams interfaced their dot controller board to the DM screen & its board using whatever control signals that 3rd party board required. If it is the high voltage on that board that is causing the changing brightness on your screen it might be repairable. On older equipment like this, especially on display devices, one of the first suspects is the old capacitors, they tend to dry out & degrade over time. A common repair from tech shops to older display equipment is to do a "re-capping" which replaces old electrolytic capacitors. I don't know of repairs to the DM screen board that have been done by anyone here or elsewhere but it's possible.

For someone fairly new to this area you've done very well on your repairs, don't let any setbacks get you down.


You probably are getting 100% of the headaches of getting the machines running, but remember the old saying "Happy wife makes for happy life".   











 

[Tmmybahama]

So I switched out the display in the JSD with the one in the (game formerly known as) Perfect Match. Obviously, the problem is in that display. I fear, however, that the power supply for the display is on its' last leg. It came on bright and clear and worked fine for awhile. Then , it would kinda dim. When the picture changed it would be bright again, and then dim. Finally it went into continuous dot fail.  Has anyone here attempted to replace the display with an LED or similar? I have found same size led displays that simulate a DMD on AliBaba and was wondering about compatibility/power requirements/etc.

Side note: A fellow member was kind enough to make me the game roms and said they are "97%" chips. I firmly believe that the wife is benefiting from the 97% and I am getting the 3%. 

WORKS THE SAME WAY WITH MY WIFE ON THE 97%/3%; It might just be a "WIFE" thing....  Also, I did notice that with all 3 different games I owned on probably 20 machines I had refurbished and sold/played, they were VERY STREAKY.... Sucks up about 100 bucks, 75 cents at a time, really hitting just small things here and there, and then bam!  Win 50 bucks, 100 bucks, even 200 bucks on a few bonuses that pop up or a 1000 coin hit on Jackpot Party, etc etc, and then itll take most of it, or all of it and some (usually the latter), just to start the "streaky" run patterns all over again....  Just how Williams DOT GAMES, In My Experience have played out...


Really have enjoyed this thread here; I just sold the last 10+ DOTs of mine to a member here, but I sure loved em and I am sure I will be getting many more in the near future and every little bit of info I can learn from problems others have and figure out and post on here, the better for all of us... So, sorry you had problems and headaches, but others have benefited from those problems......

[Mk1Mod0]

If it was easy, everybody would do it. Right? Whenever I load up a wreck of a pinball that was two steps from the dumpster some folks in the community think I'm nuts.  Their thought is that for X amount of money more I could get a nice working example. My reply is where in the heck is the fun in that? This IS the fun part to me. Sure, it gets frustrating sometimes when I just want to play and the machine... well not so much. But I always get over it.

The DMDs were built by the Cherry Corp out of Waukegan, Il.  They are no longer in that business. According to their website they now produce input devices and POS equipment. Looks like I will have to go digging at the pinball site to see if anyone has made progress on a swap. The problem is that companies still produce these displays including a 192 X 64 sized version for $500.  I don't know if those would work in these or not. And with replacements available most folks won't go working on a different route.  The old displays do have a step-up transformer that drives the 12vdc input to the 180 range. That would obviously have to change for a LED display. They also have  20 year old caps and diodes so I may try some replacing there. I will be pursuing this and will gladly share any useful info I can glean.

[cowboygames]

Hi All, appears you are having a good time and trading a lot of info here, glad to see that, it's what we're here for, but for future lookers and to really supply help to people it's probably time to start separating some of the issues into different topics or continue the off topic parts of the conversation through email or personal messaging. At 100+ posts it is a lot to flip through to "maybe" find a piece of info that will help with whatever problem you're researching. Thanks for your consideration and enjoy the new year!