Help diagnosing DMD problem please

[kevlar]

When I bought my Getaway from those b******s in Blackpool a year ago the DMD was ' fizzing ' a little bit ( gassing? ) on the top line of text rows ( not the top line of the display! ). Not all the time, just sometimes. I thought the DMD must be on the way out and that I would replace it when it got bad. But then it worked fine for months on end. Recently it's started again and it's all the time now. Someone saw it recently and said it's probably not the display but the display driver board, voltages probably low and replacing some components may fix it. Anyway today I decided to trouble shoot it by swapping driver boards with my shadow. The getaway display driver board in my shadow worked fine with the shadows display, no problems at all. However the shadows driver board didn't work with the getaway display for some strange reason. Why would that be? I thought they were interchangeable. I was going to bring my Indy 500 into the mix but noticed an extra chip U12 on its driver board ( it's missing on the other 2 boards ) so decided against it.

So it looks like the getaway driver board isn't the problem. Time to swap displays, the shadows display worked perfectly in the getaway with the getaways own driver board. Also the getaway display with the getaway driver board fitted to my shadow showed the same fizzing. All I can assume then is the getaways DMD is F'd.

This is how it looks;



It's always the top line of text, see how the rest of the line across the onscreen arm is fine?



Again here, top line of both rows of text. If this text was to start scrolling up like when credits are displayed the fizzy line would go up with it.

Is this what I've heard referred to as gassing? Can anything be done apart from buying a new one?

Also with prices shooting up lately where is the best place to buy?

 

[Rus121]

If the driver board from the getaway works in the shadow, then I would suspect the DMD itself to be on its way out.

You can confirm this by putting the DMD from the getaway into the shadow. If its still the same in the shadow (yes, you can swap the DMDs with no problem) then the DMD needs replacing.

 

[Moonraker]

Clean the DMD ribbon cable connector with some sanding paper and see if that helps. Then try swapping the shadow's 3 ribbon cables first to confirm it's not those at fault. If the problem is still there then bring your DMD to the next meet and I'll have a look at it for you (or send it in the post before then).

 

[kevlar]

If the driver board from the getaway works in the shadow, then I would suspect the DMD itself to be on its way out.

You can confirm this by putting the DMD from the getaway into the shadow. If its still the same in the shadow (yes, you can swap the DMDs with no problem) then the DMD needs replacing.

Thanks Rus, I have tried the getaway DMD in the shadow and as mentioned above for some strange reason I'm still hoping someone has the answer to it doesn't work with the shadows DMD driver board at all. To confirm;

The Shadow DMD works perfectly with either driver board in either machine
The Getaway DMD works with The Getaway driver board poorly
The Getaway DMD does not work at all with The Shadow driver board????

It looks like the DMD obviously but I'm just curious as to why it doesn't work at all with the shadows driver board.

 

[kevlar]

Clean the DMD ribbon cable connector with some sanding paper and see if that helps. Then try swapping the shadow's 3 ribbon cables first to confirm it's not those at fault. If the problem is still there then bring your DMD to the next meet and I'll have a look at it for you (or send it in the post before then).

Thanks Pete, I'll give that a try.

 

[pinballmania]

Thanks Rus, I have tried the getaway DMD in the shadow and as mentioned above for some strange reason I'm still hoping someone has the answer to it doesn't work with the shadows DMD driver board at all. To confirm;

The Shadow DMD works perfectly with either driver board in either machine
The Getaway DMD works with The Getaway driver board poorly
The Getaway DMD does not work at all with The Shadow driver board????

It looks like the DMD obviously but I'm just curious as to why it doesn't work at all with the shadows driver board.

The shadow driver board is outputting lower volts than getaway. Your display is on the edge of death, and the lower voltages on the shadow driver board are not enough to ignite the depleted gas in the errant display.

 

[kevlar]

The shadow driver board is outputting lower volts than getaway. Your display is on the edge of death, and the lower voltages on the shadow driver board are not enough to ignite the depleted gas in the errant display.

Cheers Andy, how much are they currently?

 

[pinballmania]

The remains of my current batch are 155 plus insured p&p £6.95

Andy

 

[kevlar]

The remains of my current batch are 155 plus insured p&p £6.95

Andy

Cheers Andy, do you take part ex? Lol.

 

[pinballmania]

good try, but no.

Stick it ebay, with the pics and honest description, and i'm sure someone will buy it.

 

[Carl Spiby]

Conincidently the Getaway I have at the moment is suffering the same problem but goes away after about 10 seconds after power on.

 

[kevlar]

I ended up replacing mine and keeping the old one for emergencies.

 

[Carl Spiby]

Everyone needs an emergency DMD.

 

[abaxas]

Everyone needs an emergency DMD.

I doubt that Chuck Norris would need one.

 

[kevlar]

I'll be happy I kept it if I have one completely fail.