(Topic ID: 200522)

Granny and the Gators vidiot deluxe issue

By cooke

4 years ago


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  • 12 posts
  • 5 Pinsiders participating
  • Latest reply 4 months ago by jk
  • Topic is favorited by 1 Pinsider

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20180208_163240 (resized).jpg
2017-10-19_15h49_32 (resized).png
2017-10-19_15h53_15 (resized).png
2017-10-19_15h55_11 (resized).png
Granny screen (resized).png
VD (resized).jpg

#1 4 years ago

I've been working on a Granny and the Gators with Vidiot deluxe board issues (among other problems), but my primary concern is the vidiot board. I've managed to get the board to boot and enter the communications screen and the color bar screen, but the communications screen isn't showing me what I expect to see. Instead I only get what looks like the left-hand sidebar graphics all scrunched up at the bottom of the screen. See here:

VD (resized).jpg

I've verified all of the roms and tested the 6119 and the 74139 at U14. I've also replaced the pots, although I doubt that's related. I'm relatively certain that the TMS9928's are fine, or else I don't think I'd see anything on the screen at all. i also have a working vidiot board from a Baby Pac and swapping the TMS9928 from that board into either spot on the VD board changes nothing.

It looks to me like a rom issue or addressing problem or something, but I'm clueless with this sort of thing and hate working on video game boards, which is basically what this is.

If anyone can help, I would be very grateful. Please let me know if there's suggestions on where I can look next.

Corey

#2 4 years ago

I've found this image via google and wonder if someone can confirm that this is what the communications page should look like when it's not connected to any other boards:

Granny screen (resized).png

#3 4 years ago

Anyone out there have one of these machines that can do some testing for me?

#4 4 years ago
Quoted from cooke:

I've found this image via google and wonder if someone can confirm that this is what the communications page should look like when it's not connected to any other boards:

Working Granny here. The screen looks like your picture, blank columns under RCV and XMIT, when the Vidiot Deluxe test button is pressed (no cables pulled). The coin door test button will show numbers in the transmit and receive column. Pulling J1 & J2 from the Vidiot and pressing the Vidiot test button results in the same screen you posted two days back, ok up top and a jumble of characters down below.

#5 4 years ago

No Granny (nor Baby PM) here ! but I know the vidiot (and deluxe boards).
Indeed, without board connected you should have a screen like this one (left side is not empty): 2017-10-19_15h53_15 (resized).png
With connected board, you can see the XMIT/RCV datas:2017-10-19_15h49_32 (resized).png
And if you press again the TEST button, you get the color bar: 2017-10-19_15h55_11 (resized).png

If you get a partial video image, you can be quite sure that the TMS9928 (slave and master) works, but there is some default in the video RAM chips.
At the power up, there is a self test procedure (read the Vidiot dlx Theory of operation document - available at ipdb). The led flash depending on the test achieved. There is a video RAM test in this sequence, so it can be helpful to identify the issue.

As all chip are on socket, you can first test an interchange between the two TMS9928 - if this change nothing, this means that the video CPU are not faulty). You can also try to remove one or more RAM chip (U19..U24 and U29..U34) to try to identify which of them are deffective.

#6 4 years ago

Thanks for your messages. Biffbar, are you sure the jumble of characters down below is normal? noflip95 seems to say otherwise.

I'm thinking I should try swapping the video ram chips with the baby pac vidiot board I have here, one at a time. That could net some results. Thanks for the suggestion.

#7 4 years ago
Quoted from cooke:

Thanks for your messages. biffbar, are you sure the jumble of characters down below is normal? noflip95 seems to say otherwise.

No, no... Myself, I don't have tested with a real board. May be the garbage characters are normal ! it's strange, as the inputs from J1/J2 goes to 6821 and should normaly not interfer with the video. But may be, there is a bug in the test mode of the board (something wrongly initialized when inputs are not connected (only with pull-up resistors). - Can't confirm, as I don't have the board anymore.

1 week later
#8 4 years ago
Quoted from Biffbar:

Working Granny here. The screen looks like your picture, blank columns under RCV and XMIT, when the Vidiot Deluxe test button is pressed (no cables pulled). The coin door test button will show numbers in the transmit and receive column. Pulling J1 & J2 from the Vidiot and pressing the Vidiot test button results in the same screen you posted two days back, ok up top and a jumble of characters down below.

This reply set me in the right direction. Thanks so much!

Once I realized the VD board was working properly, I set about checking the MPU. It had a 6821 PIA that was working well enough to get the board to boot, but testing it in my tester showed it was partly bad. Replacing this chip resolved the issue and allowed the game to boot and play. I also managed to use a CGA to VGA converter board and get the game playing on a LCD monitor.

The last issue to resolve is what appears to be EMF interfering with the monitor image whenever the flippers are engaged. I've confirmed that it's not the result of vibration because the issue occurs when the flipper button is pressed even if the flipper is physically held in the up position. I'm going to attempt placing a 10k resistor in series with the sync line to see if it makes a difference.

#9 4 years ago
Quoted from cooke:

The last issue to resolve is what appears to be EMF interfering with the monitor image whenever the flippers are engaged. I've confirmed that it's not the result of vibration because the issue occurs when the flipper button is pressed even if the flipper is physically held in the up position. I'm going to attempt placing a 10k resistor in series with the sync line to see if it makes a difference.

Adding the resistor fixed this problem. And now it's a perfect Granny! Thanks for the assistance with this project.

3 months later
#10 4 years ago

I know this post is 3 months old. Hoping I can get some replys. I have the same issue with my Granny and the Gators I am working on. The thing is i have a new Ultimate Bally/Stern CPU in it. The CPU works fine in 2 other Bally machines I have. So i don't think the CPU is at fault. I have replaced the 4 connectors completely on the CPU. I have not replaced connectors J1 or J2 on the Vidiot Deluxe board yet. Waiting on more supplies. Do you think this could be the problem that could be causing this. Any other ideas that you could throw out there would be great also. Thanks

20180208_163240 (resized).jpg

#11 4 years ago

I got a new CPU in today. No change at all. So i am waiting on the new connectors. Just wandering if the J1 and J2 connectors could cause this. If it's not them what else could it be?

3 years later
#12 4 months ago

I just had this same issue and it ended up being bad fuse clips on the power supply.

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