I have a demolition man that has problems starting up. I recently purchased the machine and it ran fine except the sound didn't work. Then I had a problem with the display not working right and now the machine won't startup. If I disconnect the 34 pin ribbon cable from the display controller board the machine will startup. So, I replaced all of the components on the display controller board that are directly connected to the 34 pin connector. Nothing has changed. I am not sure what the next step is that I should take.

I am trying to learn how these machines work, not to pay someone to fix it for me. Since I am not familiar with this machine I was hoping to get some hints on what to look at. I don't mind working on them myself.

Hopefully I didn't miss any of the connectors. The voltages are as follows on the power driver board:
J107 pin1 5.6v
J107 pin2 5.6v
J107 pin3 5.6v
J107 pin5 21v
J107 pin6 21v

J104 pin1 4.8vac
J104 pin2 4.8vac

J114 pin1 12v
J114 pin2 12v
J114 pin3 5v
J114 pin4 5v

J118 pin3 5v
J118 pin2 15v

There was a bad connection at the interlock switch. I now have 52vac at J104.

No change.

I did that. When I turn it on the three lights work as follows:
First the top and bottom lights are on.
After short time the top light turns off and the middle light flashes continuously.

What is the next step? The website you referenced is for Data East machines.

All working now. It turned out to be a connection problem between the boards. Now I have to go back to my original problem of no sound.

I get no sound at all except when I turn it on or off I get a pop out of the speakers. I hooked up a different speaker and got the same results. I had found a couple of broken traces that I fixed. They didn't make any difference. The sockets all look clean. Overall the board is pretty clean.

This machine doesn't have a pot for volume control. The volume is changed electronically with the buttons on the coin door. I can change the volume setting and it shows the level changing on the display, but it does nothing.

On the MPU W1 jumper is in. I tried reseating all of the connectors. No change after doing so.

I don't have any other WPC machines.

I don't have a chip puller for U9. I did push on it and that made no difference.

I bought a chip puller and reseated U9. Still no change. I then bought another sound board. It is used, but was sold as working and did work just before it was sent to me. It is doing the same thing as the original board. The only thing that is common between the 2 boards are the EPROMs. So, I am going to replace the EPROMs to see if that helps. The question I have is: isn't the sound board supposed to make a sound even if it isn't hooked up to the CPU board? Also is there something else I should be looking at?

All that happens when I turn on the machine is I get a load pop sound. The same thing happens when I turn it off. It does the same thing if the ribbon cable is connected or not connected. I didn't change the ribbon cable because the sound board doesn't seem to be working on its own. I also checked continuity of the cable and everything was good.

Unfortunately I don't have a cable. So, I just ordered a cable. I will provide an update when I get it.

I only purchased the cable that goes to both the sound board and the display driver board. I was thinking I had another unrelated problem with the display, but now I am thinking it may be related. The display was working fine and the game played fine, just no sound. Then the display started to look like a graphic equalizer. Now I wonder if the problem is the cable that goes to both the sound board and the display driver board. Originally I assumed the DMD went bad and I ordered a replacement. I also ordered the HV rebuild kit for the display driver board. So, hopefully one of these things fixes my problems.

I just ordered the complete set of cables from GPE.

The hv at the dmd is 130 and 111. That seems to be a little high. I am not sure that will cause a problem. The other reason I was going to rebuild the hv is it has gotten real hot to the point that there is very little solder on some of the connections and many of the pads are real dark. I just received a new display and plugged it in and it works fine. So, it looks like the original display has a problem. I assume it is the board and not the display itself.

I rebuilt the HV and the voltages have gone higher. They are now 138 and 116. Now I am afraid to plug in my new DMD.

I noticed it was marked as resolved, not sure how that happened. I don't see a way to reverse that.

I installed the new cables and I now have sound. In addition my original DMD is working again. The only thing that is still a problem is I still get the pop sound when I turn it on and again when I turn it off. I assume that indicates a power problem but I am not sure where to look.

Thanks for all of the help.

With the DMD plugged in the voltages are still at 138 and 116.

It is much more enjoyable with sound. I was just playing it and the sound went out again. I found another flaky connector. When I push on connector J3 I can make the sound turn on or off. So, it looks like that is the next fix. Hopefully that will finally fix everything.

This was a good learning experience. I wanted to go directly to the expensive fix of replacing boards when it looks like all of the problems were connection related. I still need to verify if my original sound is functional, but I suspect it is.

I want to thank everyone for all of the help.

I reflowed all of the solder connections near J3 and the sound board is working well now. My problems continue though. The DMD will work sometimes and then all of a sudden it looks like a graphic equalizer. I tried another DMD and it works but I get some ghosting around some of the characters.

I tried the original board that came with the machine, but I can't get it to work.

The original one that came with the machine (Babcock) is the one that works sometimes. The other one I tried (Vishay) is the one that has ghosting.

I reflowed the solder on all of the connector pins for the 3 ribbon cables and pulled U9 and reseated it. There is no improvement. Now the display is doing something different. It is getting waves of pixels moving down the display. I tried to upload a video but I keep getting an error. Something about not having an upload id. As soon as I can get that to work I will attach it.

I looked for shorts and didn't find any. I am going to look at it again just in case I missed something. The other display, Babcock, just has pixels down at the bottom. It looks a lot like a graphic equalizer display and changes as different things are displayed.

I just tried reseating the game roms and that made no difference.

I haven't seen any verification if the voltages are ok. I even looked at other postings and couldn't find anything. I just checked the voltages again and they are 134 and 113. Seems strange that they have changed since I haven't done anything to the power section of the board.

I used all of the parts that came with the rebuild kit.

I uploaded videos of the displays to youtube. The first video is the Babcock display and the second one is the Vishay display.

I don't know, I don't have another machine to test them in.

Well, I hate to buy more boards I may not need, but I just ordered a new Rottendog replacement board.

I am helping my son move from Michigan to Houston the last week of Oct. He is also a pinball collector. I will have to let him know about the expo. Maybe he can make it to the show.

Yes, my measurements are good except the first 2 which are 134 and 113. They are high the only question I have is if they are too high for the display to work correctly. I will find out when I get my new display board.

Yes I rebuilt the hv first then replaced the cables. So, at one point the displays were working fine. It is possible there is something wrong with the display board since it was working and I have been getting different results without changing anything and all of the current problems have revolved around the displays. So, it is possible the rebuild has a problem since the voltage went up after I rebuilt it. Also the Babcock display had some flakiness right when I first got the machine. One time before I touched anything the display went garbled and then started working correctly. So, I thought it might be starting to go bad and purchased the replacement display.

Right after rebuilding the hv they were -138 and -116, but when I checked it today it was -134 and -113.

Well, I just installed my new Rottendog DMD controller board. I figured I would check the voltages on that board since I was having so many problems. All of the voltages looked good except the -125v. I am getting -141 without DMD connected and -138 with DMD connected. This is very strange that it is similar to my other board. I sent an email to Rottendog to find what is going on.

The babcock display still looks like a graphic equalizer. The Vishay display looks perfect. I haven't turned it back on because I am afraid the display is going to burn up.

I talked to Jim at Rottendog and he told me that with that high of voltage I shouldn't turn the machine on again. I am sending the board back to him to get repaired.

I got my DMD controller board back from Rottendog. He didn't charge me anything. There was nothing wrong with the board. He put a note in the package to ignore the -125v test point.

This was a real learning experience for me I want to thank everyone for the help you provided.