New! Dark mode!

Browsing Pinside at night? Getting tired of all the white? Switch to dark mode using the button in the top right (or CTRL-B)!

(Topic ID: 277062)

DMD Display Non-Working in a Scared Stiff


By Mikespinball

45 days ago



Topic Stats

  • 24 posts
  • 4 Pinsiders participating
  • Latest reply 38 days ago by ChrisHibler
  • No one calls this topic a favorite

You

Linked Games

Topic Gallery

There have been 3 images uploaded to this topic. (View topic image gallery).

20200910_170034 (resized).jpg
20200910_170018 (resized).jpg
20200910_170130 (resized).jpg

#1 45 days ago

I am working on a Scared Stiff pinball machine.  The issue I am having is the color DMD display is non-working.  The machine itself appears to work fine, plays a game with no issues, but just no display. 
Below is what I have tested and eliminated to be working.

1) Removed SS color DMD display and tested in a Williams Monster Bash that had a color DMD working in it.  The color DMD out of the SS machine did work in the MB machine.
Note: I am getting power to the color display as I can get the display to go to the menu while in the SS machine. Also I did update the SS color display firmware just to make sure this was not an issue.

2) Traded the two ribbon cables that go from the CPU to the AV board and the one from the AV board to the DMD display from the SS machine and tested them in the working MB machine.  All three were tried at the same time and did work the color display in the MB.

3) I did try plugging in an older working orange DMD display in the SS machine and tested.  This display did not work either.

Note: The WPC95 Audio Visual Board is a newer Rottendog board.  The CPU board has a newer updated ROM in it.
So, which board do you think is at fault?  The CPU or AV board?  Or could it be the newer updated ROM chip in the CPU board that is at fault?

Any recommendations as to what to test next and/or which board is at fault.
Thank you for your help.
Mike

#2 45 days ago
Quoted from Mikespinball:

The CPU or AV board?

Could be either. Is there any battery corrosion at all on the CPU board? If so, likely that is where the issue lies.

First try to press on all the socketed ICs on the CPU board? If it didn't help, I would swap in the MB AV board into the SS. No need to swap the sound ROMs between the boards. Only will have wrong sounds, which will not hurt anything.

If you want to try the CPU board, you only need to plug in the J210 power connector and the 2 ribbon cables at the top of the CPU board to test out the ColorDMD.

#3 45 days ago

Thank you for your help. I will check out what you recommended and report back.

#4 44 days ago
Quoted from PinballManiac40:Could be either. Is there any battery corrosion at all on the CPU board? If so, likely that is where the issue lies.
First try to press on all the socketed ICs on the CPU board? If it didn't help, I would swap in the MB AV board into the SS. No need to swap the sound ROMs between the boards. Only will have wrong sounds, which will not hurt anything.
If you want to try the CPU board, you only need to plug in the J210 power connector and the 2 ribbon cables at the top of the CPU board to test out the ColorDMD.

Okay update:
1) Is there any battery corrosion at all on the CPU board?
There is none present, but the battery has been replaced with a NVRAM battery eliminator. Also the ROM chip has been replaced with a KSARCADE.NET 1.5 SS chip.
I did carefully remove all removable chips, check their legs and reinserted them. Then tested with no change.

2) I then did swap in the MB AV board into the SS. No need to swap the sound ROMs between the boards. Only will have wrong sounds, which will not hurt anything. Note: In these tests all I did was turn on the machines for testing the display to see if the display worked.
The MB AV board did no change to the SS display, but also put the AV board out of the SS into the MB and it did work the display in the MB machine.
So inclusion I would assume the AV board out of the SS is in good working condition as it did work in the MB machine.

3) If you want to try the CPU board, you only need to plug in the J210 power connector and the 2 ribbon cables at the top of the CPU board to test out the ColorDMD.
I then installed the MB CPU into the SS machine and only plugged in J210 and the two ribbon cables and tested. Machine came on with normal bong and display worked! The display did come up, but with an error message of check F106 and F101 fuses. I did check these fuses and they are in working condition. The machine did have an error message before with the original SS CPU in as the machine did dong, dong, dong after the initial one dong once its turned on (error message), just did not know what as I could not see this due to the non-working display.

Okay, the display problem appears to be with the main CPU board that has an issue, but what to check for next? Traces appear okay and have beeped them out with my meter as best I can. Also is there an second issue with the driver board with these fuses or is this just because not all connectors installed when I tested the MB CPU board in the SS machine? Not sure because the machine had this issue before I traded the SS CPU for the MB CPU.
Final note: Machine does play a game and appears to have no other problems other than some minor switches that need to be adjusted and/or replaced.

Any additional help would be appreciated.
Mike

#5 44 days ago

Can you post a good picture of the CPU board, especially under the battery holder area? Also need to see the part number/revision of the board. Normally, I think it is along the top side edge of the board.

#6 44 days ago
Quoted from Mikespinball:

The display did come up, but with an error message of check F106 and F101 fuses. I did check these fuses and they are in working condition.

You can ignore that error message. It likely came up because the switch harnesses weren't connected to the CPU.

#7 44 days ago

Just making sure..you tried the SS CPU board in MB?

Also in the process of moving it over, put the board down flat on a table and press on the socketed ICs again. You probably will be hearing some more crunching sounds as the parts are pushed in more securely.

#8 44 days ago
Quoted from PinballManiac40:

Can you post a good picture of the CPU board, especially under the battery holder area? Also need to see the part number/revision of the board. Normally, I think it is along the top side edge of the board.

Here are a few pictures of the SS CPU board.
No part number/revision at the top, but one on the right side.

20200910_170018 (resized).jpg20200910_170034 (resized).jpg20200910_170130 (resized).jpg
#9 44 days ago
Quoted from Dmod:

You can ignore that error message. It likely came up because the switch harnesses weren't connected to the CPU.

Great! Thank you for the information.

#10 44 days ago

Don't forget to press on the U9

#11 44 days ago
Quoted from PinballManiac40:

Just making sure..you tried the SS CPU board in MB?
Also in the process of moving it over, put the board down flat on a table and press on the socketed ICs again. You probably will be hearing some more crunching sounds as the parts are pushed in more securely.

I did not try the SS CPU board in the MB machine yet, but can if you want me to.

#12 44 days ago
Quoted from Mikespinball:

I did not try the SS CPU board in the MB machine yet, but can if you want me to.

Yes, that will confirm the problem is with the board. Again, you can just hook up the ribbon cables and J210. We are just interested in whether the DMD is working with the CPU board.

#13 44 days ago

Okay great, I will re-push on the socketed chips and test the SS CPU in the MB and will post an update. Might not get this done until tomorrow, but will let you know what the results are.
Thank you all for your comments.
Mike

#14 44 days ago

Okay went back in the garage and tested the SS CPU board in the MB. First I pushed on all socketed chips along with U9. Normal creaking. Once turned on got the normal one dong, but no display.
I guess this determines the issue is with this board.
What's next to check?
Let me know,
Thanks
Mike

#15 44 days ago

At least it is confirmed as a CPU board failure. Is the L201 blanking LED solid lit and the middle L203 diagnostic LED is blinking?

#16 43 days ago
Quoted from PinballManiac40:

At least it is confirmed as a CPU board failure. Is the L201 blanking LED solid lit and the middle L203 diagnostic LED is blinking?

L201 is off
L202 is on
L203 is blinking
This is what the SS CPU board shows while in the MB machine.
This same thing shows on the MB CPU board while in the SS machine.
Let me know what you suggest next to do.

#17 43 days ago

Can you try reseating the 40 pin CPU chip and the game ROM?

#18 43 days ago
Quoted from PinballManiac40:

Can you try reseating the 40 pin CPU chip and the game ROM?

Okay did those reset with no changes.
Also I buzzed out tested traces between U1, U3 and J201, J202. All checked out in working condition.
What's next?

#19 43 days ago

I haven't had to do a lot of debugging on the WPC MPU board so take this for what it's worth...

If the sound is working then that suggests address/data are getting from the MPU to the A/V board. (Although it's possible there's a higher order address bit that could be stuck and preventing data from getting to the video address space.)

The more likely problems are an issue with the FIRQ line that comes back from the A/V board and the BLANK that goes out to the AV board.
FIRQ is pin 34 on J202
BLANK is pin 27 on J202

If the FIRQ isn't being detected properly on the MPU, it will interfere with the display pages being updated. You may want to check to make sure that signal is toggling on the MPU. You will probably need a logic probe, or oscilloscope to confirm it's toggling.

The other really important signal is the BLANK since this is logically NOR'd with another signal on the A/V board to produce the DISPLAY_ENABLE that goes out to the DMD. If the BLANK is stuck high, the display will never light up.

Both of those issues could be caused by a defective U9 or poor socket connection. You can try swapping U9 from the working board to see if it resolves anything.

#20 43 days ago
Quoted from Dmod:

I haven't had to do a lot of debugging on the WPC MPU board so take this for what it's worth...
If the sound is working then that suggests address/data are getting from the MPU to the A/V board. (Although it's possible there's a higher order address bit that could be stuck and preventing data from getting to the video address space.)
The more likely problems are an issue with the FIRQ line that comes back from the A/V board and the BLANK that goes out to the AV board.
FIRQ is pin 34 on J202
BLANK is pin 27 on J202
If the FIRQ isn't being detected properly on the MPU, it will interfere with the display pages being updated. You may want to check to make sure that signal is toggling on the MPU. You will probably need a logic probe, or oscilloscope to confirm it's toggling.
The other really important signal is the BLANK since this is logically NOR'd with another signal on the A/V board to produce the DISPLAY_ENABLE that goes out to the DMD. If the BLANK is stuck high, the display will never light up.
Both of those issues could be caused by a defective U9 or poor socket connection. You can try swapping U9 from the working board to see if it resolves anything.

What you have said here makes sense. Unfortunately I don't own an oscilloscope, but due own a logic probe. Have not had a use for it since college and that was 1985! Anyhow I appreciate your advice and may take you up on it. Lastly I don't have the proper tool to remove U9.
At this point the issue appears to be more than what I want to tackle and I feel it maybe best for me to send the board in for repair by a professional.
Again thanks all for your help and advice.
Mike

#21 43 days ago

chrishibler would be happy to look it over.

#22 40 days ago

Interesting problem. Happy to take a look.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact
http://www.PinWiki.com - The new place for pinball repair info

#23 39 days ago

Hi Chris,
Thanks for offering to look at this, but already sent it in to The Coin-OP Cauldron with Clive. I have used Clive for many years now and have had great success with the board repairs from him. I will keep you in mind through.
Mike

#24 38 days ago

Mikespinball, no worries. Clive is a good tech.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info

Promoted items from the Pinside Marketplace
From: $ 42.00
Cabinet - Shooter Rods
ModFather Pinball Mods
£ 49.00
Playfield - Other
PinballToys

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside