DMD High Voltage board problems???

[ktm450]

A while ago my WH20 display started to take approx. 30 sec - 1 min before it would 'display' I figured it was getting old as it was a little duller, and would probably need replacing soon, yesterday it wouldn't display at all, I checked the voltages the -120v on the first two pins and where there should be a difference of 12v between them there was only 2v.  I figured the HV needs to be rebuilt (or one of Mikes HV piggybacks) but I thought I'd try the display in another pin to double check.

Sure enough the display still works although a little duller that a couple of my other games no big dramas, I put a couple of old displays into WH20 to check if it was indeed the HV section, they worked for a second then blank displays again.

Then I pulled a Dale Vishay DMD from another working game and put that int WH20 and it works fine, and displays immediately, the -120v had a difference of 11v I think. Weird 

I have heard that the Dale Vishay use double the 5v current that other displays use and can sometimes be a factor in causing game resets etc.

I wonder if the electronics on the Dale Vishay, being obviously different, help the matter or not???

I know that Bally/Williams games don't need all the DMD electronics on the back like Data easts use, but thought it was interesting.

I'll hold off the HV section fix for the time being and see what happens.


Meanwhile any of you electronic gurus have any thoughts?

Am I going to damage the HV section drawing extra current through an old display? I remember Clay saying he had done some testing and that fact was disproven??  It was all relative to the amount of dots displayed at any time

Should I just bite the bullet and buy Mikes HV piggyback or rebuild the HV knowing there is obviously some sort of problem there anyway?

Thanks guys,

Matt.

[Caveoftreasures]

I reckon rebuild the HV section.

I have a display on my Royal Rumble that does the same thing. Works perfectly for 50 start ups, then goes funny for 3 or 4 start ups then shows all lines lit up and does weird stuff. I took it out and shoved it in another machine and it did NOT do anything weird. But the other display I put in the Royal Rumble started doing the same weird stuff which it had never done before, so I know its a votage issue and I will get Beaky to check the dmd driver board/and the voltages in general.

IF you are going to buy a new DMD, Mad Amusements in the USA have them for $129, postage is around $25 to $35 and the more DMD displays you buy, the cheaper they are and the postage drops as well. A good idea would be to order for ya friends and mates who also want a new DMD display and share in the costs.  

http://mad-amusements.com/product.php?id_product=236  

I tried local suppliers, but they cannot match the USA supplier who buys in bulk.  

[MartyJ]

I reckon rebuild the HV section.

I have a display on my Royal Rumble that does the same thing. Works perfectly for 50 start ups, then goes funny for 3 or 4 start ups then shows all lines lit up and does weird stuff. I took it out and shoved it in another machine and it did NOT do anything weird. But the other display I put in the Royal Rumble started doing the same weird stuff which it had never done before, so I know its a votage issue and I will get Beaky to check the dmd driver board/and the voltages in general.

IF you are going to buy a new DMD, Mad Amusements in the USA have them for $129, postage is around $25 to $35 and the more DMD displays you buy, the cheaper they are and the postage drops as well. A good idea would be to order for ya friends and mates who also want a new DMD display and share in the costs.  

http://mad-amusements.com/product.php?id_product=236  

I tried local suppliers, but they cannot match the USA supplier who buys in bulk.  

Brett,

On most occasions if you are getting garbage (jumbled lines, or dots all over the place) this is due to a poor data connection to the DMD - ie ribbon cable.  Most likely when you've changed the displays out you have reseated the cable giving it a temp fix.  I always change out ALL ribbon cables on my games or customer machines to give trouble free operation for years.  Greg from RTBB carries most if not all the ribbon cables required for machines.

[beaky]

I will make you up a set brett, next time i am at jaycar i will buy the parts mate.

and matt if your dmd driver pcb isn't badly heat damaged just rebuild it (HV section). I do these on a regular basis. I replace every component good or bad including bridge rectifiers. (I always do a full rebuild not a partial patch up)

but if the board is heat damaged then the homepin board is the way to go

[ktm450]

and matt if your dmd driver pcb isn't badly heat damaged just rebuild it (HV section). I do these on a regular basis. I replace every component good or bad including bridge rectifiers. (I always do a full rebuild not a partial patch up)

but if the board is heat damaged then the homepin board is the way to go

No heat damage luckily, are the components available locally Andrew? I know Great Plains used to sell a kit but I haven't got around to sussing the rebuild out yet

[Homepin]

and matt if your dmd driver pcb isn't badly heat damaged just rebuild it (HV section). I do these on a regular basis. I replace every component good or bad including bridge rectifiers. (I always do a full rebuild not a partial patch up)

but if the board is heat damaged then the homepin board is the way to go

No heat damage luckily, are the components available locally Andrew? I know Great Plains used to sell a kit but I haven't got around to sussing the rebuild out yet

I can do you a kit for $14 (no bridges but all the other parts).

[Caveoftreasures]

Good idea MartyJ. I am always telling Beaky look for the most simplest, easiest of reasons for machine farkups. I shld take my own advice. I never thought about replacing the old ribbon cables.

When the dmd plays up, every line (or every single dot) on the display is lit up. I think I will change out the ribbon cables and see if the funny stuff stops. Thanks for the heads up. (I did this on my batman forever with the marco's upgrade cable and it worked a treat cause those larger dmd suckers are like $425 each  )

I have ordered in a bunch of new DMD displays from Mad Amusements. At that price, I can help myself. 

[pinnies4me]

I can do you a kit for $14 (no bridges but all the other parts).

Handy to know Mike.

[ktm450]

and matt if your dmd driver pcb isn't badly heat damaged just rebuild it (HV section). I do these on a regular basis. I replace every component good or bad including bridge rectifiers. (I always do a full rebuild not a partial patch up)

but if the board is heat damaged then the homepin board is the way to go

No heat damage luckily, are the components available locally Andrew? I know Great Plains used to sell a kit but I haven't got around to sussing the rebuild out yet

I can do you a kit for $14 (no bridges but all the other parts).

Thanks Mike PM sent

[beaky]

if you decide to replace the bridge rectifiers also I carry them in stock.

[ktm450]

if you decide to replace the bridge rectifiers also I carry them in stock.

Thanks for the offer mate, but I have already ordered the bridges 

[ktm450]

Thanks Mike, installed all the components a week ago all good.
Mike sends out an envelope with all the components layed out and taped to a sheet of paper with the location and ratings of each, making installation a breeze, nice work mate

[Homepin]

Glad your problem is sorted - well done