Williams No Fear: Dangerous Sports (Williams, 1995) DMD problem

[Decept]

I have a Williams No Fear machine where the DMD sometimes shows garbled graphics. Lately its been happening more and more often, you can hardly finish a game anymore. Sometimes the DMD goes back to normal again.
I tried cleaning the power and data connections, but it didn't help.

I attached a photo of the display.

Any help would be much appreciated.

 

[pinballdaveh]

possibly a high voltage issue. on the dot matrix controller board,( top right board in head ) . using a dmm check voltages on j604 ( 8 pin jack bottom left on board) pins 1-8 should be right to left and should be marked. connect black lead of dmm to ground strap, set range for 200 volt dc . pin 1 orange wire -125v , pin 2 blue -113v , pin 6 grey +5v , pin 8 brown +62v. on j606 ( left side lower jack ) check pin 4 grey +5v , and pin 6 grey-yellow +12v . the -125v and the -113v 12 volt differential is critical for correct operation . some machines use a 100v and 113v for high voltage but the 12v differential is still there . if that differential is not there on your machine , common bad parts are resistors. R3,R12,R6,&R13 47k 1/2 watt near C4 cap. to check resistance on these one lead of resistor must be desoldered and lifted away from board. other bad resistors might be the 5 watt resistors , R8 4.7k , R9 1.8k , & R11 120 ohm. these resistors can be checked in circuit without any desoldering. if problem is data related ribbon cables or connections might be at fault.

 

[Decept]

Thanks for the detailed information. I bought a new data cable but that didn't help.
I was about to do some measurements, but before I got around to the display died. I checked the fuses and one fuse on the Dot Matrix board had blown.

It's says on the fuse 3/8A 250V 313 LF. I think it's 'L' and 'F', the F is kind of inside of the L.
Does F mean that it's Fast? The manual says it should be SB, which as far as I know is Slow Blow. Part number: 5731-12328-00.

Apparently it's not that easy to find 3/8A here, is 400mA alright you think?

 

[pinballdaveh]

400 milli amp and 3/8 are close enough to use. 313 i believe is a slo blo manuf. number. if the manual calls for slo blo thats what you put in. if the fuse blows right away , a short or problem exists that must be solved or it will keep blowing fuses.

 

[Decept]

So, I replaced the fuse and started the machine. Immediately there was smoke from the DMD controller board. I turned if off at once and saw that the resistor R5, right next to the fuse, was blown.
I replaced the resistor with a new 120 Ohm, but 1W instead of 1/2W. Started it up and it worked.
After a while I noticed that there was strange flickering on both sides of the display. I left the machine on for a couple of hours, playing from time to time. At the end of the day the display only showed some strange graphics, so I turned it off. I also noticed that it gets very warm, especially around the three heatsinks near the fuses. I haven't checked for heat before, so I'm not sure how hot it's normally.
That was yesterday. This morning I turned it on again, but there is no picture at all. I think I need to measure it some more.

 

[Decept]

After some more measurements, on j604, pin 1 (orange) and pin 2 (blue) give me 0 voltage, 6 and 8 are correct. j606 is correct.

Regarding resistors R3, R6, R12 and R13. The game's manual (from ipdb) shows them as 4.7K but crossed over and 47K written instead. Is that a correction of only the manual or was there 4.7K on the board that should instead be 47K?

 

[Decept]

I got tired of trying to repair it and bought a new controller board from XPin. The XP-WPCDMD-CTRL. Now the display show the XPin splash screen, but nothing from the game. I tried the debug mode, but it only shows that the display works correctly. I tried reconnecting the data cables at every connection, but that didn't help.
There are a bunch of LEDs on the board but no info about them.

 

[Decept]

I got an answer back from XPin. It was an easy fix, dip switch #4 needs to be on. The instruction sheet says switch #4 is reserved.

The DMD works great now

 

[Decept]

The original problem is back. This is getting tiresome. I thought it might be heat related, but the machine has been off for two days and the display was still garbled as soon as I turned it on.
Can it be that it's not getting enough power?

 

[pinballdaveh]

the problem might be in the DMD driver board( the board behind the display). of what i see on the schematic there are electrolytic caps just after the 5 and 12 volt inputs. 10 and 47 MFD values are shown. these type of caps go bad after time , start leaking and causing problems. cap replacement kits are popular but i didnt find one for the DMD driver board. when replacing these caps install them in the correct polarity(+ and -) direction. caps installed wrong can explode. leaking caps can also cause board trace damage that needs to be checked or repaired before installing new caps. check all board voltages after all the electrolytic caps have been changed.