What's new
By:
Pinball info

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Dead DMD - Any ideas?

Tucks

Tucks

Registered
1 10 Years
Joined
Sep 21, 2014
Messages
2,105
Location
SW London
HI all,

Just a quick one. Turned on my TAF and the DMD was blank. Working fine a few days earlier. Game played OK, sounds, coils etc. All seem to be working but the DMD. Had a quick look in the backbox but nothing obvious.

The DMD had no lines or any visible signs of 'going bad' so wondered if it was something else? Or do these screens just fail overnight and go in the bin?

Realise this is not the most technical question you'll see on these forums and it won't tax the minds of the clever bods on here but any help would be appreciated.
 
Have you tried reseating the data and power cables? And the data cable on the graphics board? My CFTBL went very odd last month and it was the cable on the graphic board that needed a tweak.
 
I did have a wiggle of a few but no joy. I'll try again but for some reason I thought these things failed 'slowly'.
 
Resitting connectors is always a good starting point. And that involves pulling them out at both ends and plugging them back in. Maybe more than once.
But if there is nothing displayed, is it not an indication that the DMD is not powered? Have you checked the power supply to the board with a voltmeter to confirm it is getting something?
 
As Dom says, reseat connectors first and then see if the DMD is getting power. If it just went dead then I suspect a power issue. Have a look in the back of the TAF manual as it's got the display connections listed there. The connecters associated with power are J604, J605 and J606 :thumbs:
 
Power down, reseat connectors, press Asic (square chip on CPU) then power up. If no joy start measuring voltages.

David
 
Thanks all. Worst case scenario I can buy a new colour screen!
 
Mfresh said:
If I was a betting man I would bet it was the dmd driver board at fault. Try swapping that with another machine if you have one
Click to expand...
that happened with one of my machines, but the display didn't just die. The issue was the blue components that burn out over time on the driver board. Replacement cost of driver board just £95
 
These ones???

1609843545583.png

So those are capacitors.... They have a general working lifetime of 20-25 years, so we will start to see more and more of these going now as they get older... :(
 
Paul said:
These ones???

View attachment 129400

So those are capacitors.... They have a general working lifetime of 20-25 years, so we will start to see more and more of these going now as they get older... :(
Click to expand...
Yes, those were the ones - all blackened / burnt out on mine. I got a replacement board for £95 which wasn't too bad.
 
I've re-seated all listed above and checked that that power is getting to the DMD which it is.

Can the blue capacitors be tested while still on the board?
 
Unlikely to be the blue smoothing caps (although granted they're getting old and ought to be replaced), more likely to be an issue in the high voltage area - a well known failure point, you can even buy rebuild kits for that area.

Just scroll down a little from the link here to see the area with parts removed. Could be a broken part or PCB trace.
https://www.pinwiki.com/wiki/index....agram_for_WPC_and_WPC-95_DMD_Controller_Board
 
Tucks said:
I've re-seated all listed above and checked that that power is getting to the DMD which it is.

Can the blue capacitors be tested while still on the board?
Click to expand...

When you say that , do you mean that you have all four required power supplies at the dmd. ? 5v 63v and approx -113v and -125v. The 12v difference in the negative values is essential.
 
OK. Did a re-check as follows:

(Colours may not be exact but in the correct order)

While connected to DMD

Orange -116.2
Blue -117.6
Space 0
Black 0
Black 0
Grey 4.88
Grey 12.32
Brown 65.2

While disconnected.

Orange -116
Blue -92
Space 0
Black 0
Black 0
Grey 4.89
Grey 12.29
Brown 65


So the 'Blue' seems different when connected.

Is this any help ?
 
Last edited:
As a quick update, I had my DMD tested with the help of Flipout and it seemed to work fine so I'm moving onto the controller board.

Just re-seated all the ribbon cables, turned it on and the screen came on for about 5 seconds showing the version number etc and then went off again. Weirdly turning it off and on doesn't bring back the 5 seconds of display.

Does this point to a specific problem? Thanks
 
I just saw your powers, it looks like you don't have the right voltage on the blue when connected. It should be a drop of 12v from the orange wire when connected and 20v when not connected.
Have you tested at the display board end, J604 to see what the board is kicking out?
However, I would move to look at broken solder joints on the display board. Does it work or flash up as you move the speaker panel about?

I didn't fix mine, I bought a replacement.
 
You must log in or register to reply here.
Back
Top Bottom