I need some clarification help on a DMD board.
1) I got the board to work... tests fine etc.. no issues.
2) Put game in game over mode. Bad graphics.
2a) Missing brown halftones. All bright fonts/parts of graphics present.
2b) Plus flickering/sputtering animation.
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Many thanks for your inputs.
Cheers.
Weird.
Does display test result in “RAM TEST OK”?
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info
Quoted from ChrisHibler:Does display test result in “RAM TEST OK”?
Yes it does. The DMD test function works perfectly.
However, it does not test the half tone shades.
I believe Gottlieb is the only one that puts out a shade pattern.
Quoted from vec-tor:I need some clarification help on a DMD board.
If you are seeking clarification on whether or not it's worth repairing it then I would say no way. With everyone jumping on color DMD upgrades, it seems people are offering up used, working DMDs for under $50.
Has the issue been isolated to one or the other, DMD panel or DMD controller board?
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
https://www.youtube.com/c/ChrisHiblerPinball
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Quoted from snyper2099:Also, could it be a bad ribbon cable or bent pin?
No.. I can plug in a working board and everything is fine.
I guess it is another butt burner repair. I was hoping somebody
had information on the dot timing control system to the board.
All bright fonts show perfectly fine. Test functions perfect...
However, game graphics/animations, flawed/erratic.
If the display test is passing and you're missing dot intensities at the display, it's generally a problem with the page flipping the DMD controller board does as it reads data out of the video RAM and sends it to the display. IIRC, this is controlled by the DISPAGE (U31) and NEXTPAGE (U32) registers on the DMD controller board. The CPU updates the displayed page on FIRQ interrupts.
WPC data is sent in a pattern of two repeated frames (high page) followed by a single frame (low page). If you're only seeing one intensity it's either because all three frames are the same (i.e. all are reading from the same memory page) or one of the page pointers is faulty.
Quoted from Dmod:If the display test is passing and you're missing dot intensities at the display, it's generally a problem with the page flipping the DMD controller board does as it reads data out of the video RAM and sends it to the display. IIRC, this is controlled by the DISPAGE (U31) and NEXTPAGE (U32) registers on the DMD controller board. The CPU updates the displayed page on FIRQ interrupts.
WPC data is sent in a pattern of two repeated frames (high page) followed by a single frame (low page). If you're only seeing one intensity it's either because all three frames are the same (i.e. all are reading from the same memory page) or one of the page pointers is faulty.
Dmod Hi Randy.
Do you have something documented to explain the operation of the Williams Dot Controller that I can add to the PinWiki?
The logic on that board is a bit complicated. I've never taken an in depth look at it.
It would help to have the Williams ICD (interface control document) for the board. Argh.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
https://www.youtube.com/c/ChrisHiblerPinball
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Quoted from Dmod:If the display test is passing and you're missing dot intensities at the display, it's generally a problem with the page flipping the DMD controller board does as it reads data out of the video RAM and sends it to the display. IIRC, this is controlled by the DISPAGE (U31) and NEXTPAGE (U32) registers on the DMD controller board. The CPU updates the displayed page on FIRQ interrupts.
WPC data is sent in a pattern of two repeated frames (high page) followed by a single frame (low page). If you're only seeing one intensity it's either because all three frames are the same (i.e. all are reading from the same memory page) or one of the page pointers is faulty.
Thank you @dmod, Randy.
I was trying to find DMD theory of operation.. to isolate the odd problem.
Thanks again for the insightful information.
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