PIN2DMD - not working

[Frankensteinowner]

I have a 192x64 PIN2DMD on a MSF - was working fantastically but, now it won't display anything from the machine - just the boot screens.

 

I looked at the input test screens on the display - its showing 'Pin 9 close', even with the input ribbon cable removed. The resistor and capacitor check out OK. Is this right or has my board got a fault? All of the other inputs only show close when I ground the appropriate pins.

 

Looking at the circuit, pin 9 goes into a '123 which I assume is to either stretch or condition the pulse. The input to this device (from Pin 9) seems to be stuck at about 1v. The supply voltage (Vcc) is about 4.1V (which I think is needed to keep the display modules happy).  Looking on a scope, shorting pin 9 to gnd doesn't seem to trigger the '123 

 

The game has started acting very strangely - does the game processor get any feedback from the display (which if playing up could explain the problem) or is it a 'write only' device?

 

As ever, any help much appreciated - I really want to get my game back up and running!

Edited May 3, 2021 by Frankensteinowner
update

[lucky1]

3 hours ago, Frankensteinowner said:

does the game processor get any feedback from the display

No. Most likely a problem with your pinball machine. Check the 5V on your Sega DMD controller. 

[Frankensteinowner]

Thanks Lucky - I jumped 5V in from a bench supply (as the 5V was running at about 4.6V) -looking at the 68000  data bus with a scope, its in a tight loop - probably waiting for data from the game processor.

 

Should the PIN2DMD operate OK with the 5V rail at 4.06V?

 

I soooo can't get to the bottom of this - I contacted someone who fixes machines for a living but, he said he wasn't taking on new customers.

[lucky1]

On the XL panels I have lowered the 5V rail, because of some issues with some LED panels.

4.06 V is O.K.  If the sega dmd controller is constantly resetting then there is no picture. 4.6V is definitely to low.  

You should be able to test the SEGA DMD controller by connecting the reset pin (20) to GND (1).

The ROM version should be displayed.

[Frankensteinowner]

Many thanks lucky - you're a top man - just to be clear - if I ground pin 20 of the incoming data cable, it should display the rom version?   

 

The controller was resetting but, that turned out to be a corroded pin on the data cable connector - cleaned that and it stopped resetting. I'll give your suggestion a go - if I can confirm the controller is working, I'll prob make a new ribbon cable - if that doesn't fix it, just buy a new Rottendog CPU. 

 

I'll fix the 4.6V - the PSU is running at 4.99V so, the voltage drop must be in the cables.

 

Once again Lucky, many thanks for your help.

[lucky1]

43 minutes ago, Frankensteinowner said:

if I ground pin 20 of the incoming data cable, it should display the rom version? 

 

Yes

 

I'll fix the 4.6V - the PSU is running at 4.99V so, the voltage drop must be in the cables.

 

https://arcarc.xmission.com/Pinball/Stern Service Bulletins/sb/sb106.pdf

[lucky1]

43 minutes ago, Frankensteinowner said:

if I ground pin 20 of the incoming data cable, it should display the rom version? 

 

Yes

 

Quote

I'll fix the 4.6V - the PSU is running at 4.99V so, the voltage drop must be in the cables.

 

https://arcarc.xmission.com/Pinball/Stern Service Bulletins/sb/sb106.pdf

[Frankensteinowner]

Many thanks - I see the ROM images are on that link too 🙂

 

I'll also hunt down a test rom - I see there is something called Leon - if the display card / display work, I'll head down that route

 

Thanks again Lucky - I have some more avenues to try now 

[Frankensteinowner]

I tried Lucky's suggestion - nothing shown on the DMD - I put a scope on the lines to the display - only a couple of them have signals on immediately after a reset (when I'd expect to the display to show the rom version) - it looks like the controller card is defective.

 

Has anyone used the pinballSP controller with the PIN2DMD? (I see they sell their own version but, I'd rather not spend another 300 euros on one if I don't need to.