Jurrassic Park Back lights...Lower string not lighting...

[Tim N.]

Dumb question...I do have a DMD in another pin...How do I swap them? The connections dont look to match up?

It could be a voltage issue, but those are fairly close in spec. You can swap out the dmd with another one, the pins are the same, just make note of the red stripe orientation on the ribbon cable (Usually on the DMD connector it is notched to prevent reversal).

DMDs are fickle by brand, some work great in some pins, some don't. To swap.... unplug the connectors, unscrew the 4 bolts aorund the bezel and lift out. Should be easy enough and it is free to try..... In the DE game, you will have to remove the DMD driverboard before removing the display.

Give it a whirl and report back....

 

[stangbat]

If you can swap as Time suggested, that would be worth trying. A DMD that is newer could be fine with your voltages where the one in your JP may be finicky. That being said, I think the low voltage on the -98v line could be causing your dimness problems. I think that is enough for the display to look fine most of the time but dim under certain conditions. And since you have a few voltages on the low side, I think it points to an issue that probably should be addressed.

 

[stangbat]

I'd like a few more opinions here if possible. GameyMcGame's -100v reading was -87.3v. My thoughts are that this is low and can be causing the shadowing he is seeing. I have checked the voltages on my JP and the -110v is -98.1v. No problem.

I then checked the voltages on my DE SW and the -100v is -87.3v, same as GameyMcGame's JP. However, my DE SW has a brand new DMD. My guess is that its DMD is working fine with the lower voltage because it is brand new, where an older DMD may be dim under some circumstances. Anyone agree or have any other ideas?

 

[Tim N.]

I'd like a few more opinions here if possible. GameyMcGame's -110v reading was -87.3v. My thoughts are that this is low and can be causing the shadowing he is seeing. I have checked the voltages on my JP and the -110v is -98.1v. No problem.

I then checked the voltages on my DE SW and the -110v is -87.3v, same as GameyMcGame's JP. However, my DE SW has a brand new DMD. My guess is that its DMD is working fine with the lower voltage because it is brand new, where an older DMD may be dim under some circumstances. Anyone agree or have any other ideas?

I am assuming your new one is a Vishay? I think a lot of this comes down to brand/design. Dale/Cherry seem to drag down voltages quite a bit (as they are getting older now anyways). As displays start to age/gas themselves out, they will take voltage with them. As nice as Vishays are, they are real sticklers about their 5 volt. Without it being right in spec, Vishays will often not even work.

I think the artifacting that is being seen on Gamey's is a result of age of the display (which is why I thought he should swap it with another to verify).

 

[stangbat]

I am assuming your new one is a Vishay? I think a lot of this comes down to brand/design. Dale/Cherry seem to drag down voltages quite a bit (as they are getting older now anyways). As displays start to age/gas themselves out, they will take voltage with them. As nice as Vishays are, they are real sticklers about their 5 volt. Without it being right in spec, Vishays will often not even work.

I think the artifacting that is being seen on Gamey's is a result of age of the display (which is why I thought he should swap it with another to verify).

Yes, new one in the DE SW is a Vishay, and it is the one I am reading -87.3v on the -98v (-100v) line. Do you think it is dragging down the voltage? When I tested this PS in another game with a different display, I don't remember the -98v line being low.

Edit: In my previous post I incorrectly stated that GameyMcGames -110v was -87.3v. I meant the -98v (-100v) line.

 

[Tim N.]

Tim N.

Yes, new one in the DE SW is a Vishay, and it is the one I am reading -87.3v. Do you think it is dragging down the voltage? When I tested this PS in another game with a different display, I don't remember the -98v line being low.

Edit: In my previous post I incorrectly stated that the -110v was -87.3v. I meant the -100v.

No, I think you are within spec for the most part... I assumed you meant 100v..

What is your reading without a load on this connector? (I am guessing about the same)... Unless you started replacing power supply components, I dont think you will see much of a difference. Even then, it is kind of nature of the beast... I think of all the DEs Ive had (at least 15 of them), in regards to display voltages- they are either there (and fairly close to spec), or arent there at all.... if they are there, they usually work fine (other than an occasional sporadic connection from their shitty fuse holders, or cracked solder joints)....

 

[stangbat]

No, I think you are within spec for the most part... I assumed you meant 100v..

What is your reading without a load on this connector? (I am guessing about the same)... Unless you started replacing power supply components, I dont think you will see much of a difference. Even then, it is kind of nature of the beast... I think of all the DEs Ive had (at least 15 of them), in regards to display voltages- they are either there (and fairly close to spec), or arent there at all.... if they are there, they usually work fine (other than an occasional sporadic connection from their shitty fuse holders, or cracked solder joints)....

I'll check without load and report back. FWIW, this PS was rebuilt. I replaced everything but a few resistors and Zeners (Zeners at D10 and D11 were replaced though).

 

[stangbat]

Tested with no load, voltages are basically the same. -110v is -110v and -98v is -87.5v.

The -98v on my other DE PS tests at -98.1v. Why would the rebuilt one be -87.5v? Or should I just chalk this up to normal variance as you suggest and not worry? Not trying to derail this thread, hopefully this will help shed light on GameyMcGame's similar reading.

 

[GameyMcGame]

Thanks for all the data guys...Not sure, I may 'just' need a new DMD...Havent had time to try a swap. Thanks....

In the meantime, curious about the lights on top of the pin. I dont have a topper so I dont think about them much. I sat and watched a couple cycles of the attract mode and they didnt light up once....Is this a setting? If you end up paying good money for a topper wouldnt you want it lit up? just curious...

 

[tomdotcom]

Rgp quote from the man himself...

"The topper mounts towards the rear of the cabinet so the lights flash and
illuminate the front of the sign. There should be a shinny metal strip near
the front of the cabinet to reflect the light back towards the topper. LTG "

 

[stangbat]

Thanks for all the data guys...Not sure, I may 'just' need a new DMD...Havent had time to try a swap. Thanks....

In the meantime, curious about the lights on top of the pin. I dont have a topper so I dont think about them much. I sat and watched a couple cycles of the attract mode and they didnt light up once....Is this a setting? If you end up paying good money for a topper wouldnt you want it lit up? just curious...

I'd definitely try a swap before you spend any money on a PS or DMD. Hopefully we can get you all the info you need.

The topper's GI stays on constantly, so check the connector for it at the top of the backbox. It is 6.3v AC, the green wire goes to connector CN8 on the PS. The white/green wire goes to the fused output on the PPB, connector J5, and then back to CN8 on the PS. In other words, several places to check for a problem although any repairs you did to J5 on the PPB should have taken care of that portion of potential problem areas.

 

[stangbat]

Okay, GameMcGame, thanks to RGP I may have found the answer. Some displays don't use the -98v line and when it is unloaded, you'll read around -87v. It was stated that newer Vishay and some older Babcock -01 DMDs do not use the -98v. I have a new Vishay and this is why my -98 is reading -87. If you have a Babcock -01 model, this is probably your situation too and your PS would be fine. Everything seems to be pointing more towards the DMD being the culprit.

Edit: I installed a 10k ohm resistor between -110 and -98 to load the line and the -98 voltage came right up to -98.2v. So I'd bet that GameyMcGame's -98v being low is the same issue and there are no problems with your PS.

 

[GameyMcGame]

Wow, thanks for all the data guys!! I'm going to try and track down the top light issues today.