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 Post subject: Dexter and Data East boards?
PostPosted: Fri Nov 02, 2018 2:03 am 
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I've been waiting for any word that these would be supported (as getting a Road Blaster Laserdisc is quite hard) without any word. I was wondering, what exactly is preventing the data east board sets from being supported? Thanks!


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 Post subject: Re: Dexter and Data East boards?
PostPosted: Sat Nov 03, 2018 2:26 am 
DAPHNE Team
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Posts: 295
Hi!

The basic problem is that the Data East hardware for Begas/Cobra/Road Blaster requires the laserdisc player to sync its video to the graphics output of the main PCB, instead of the other way around as most games do. The video output from the Raspberry Pi can't be synced to an external source, so Dexter is unable to support these games.

There is still some hope, though. I have heard tell of a mod for these games that allows them to work with an LDP-1450 instead of the usual LDP-1000A. The 1450 doesn't have a sync input, so if the game can be changed to work with a 1450, it should work with Dexter as well.

Unfortunately, I have been trying for some time to get actual details about this mod, without success. I have a few theories about how it could be done, but I don't have complete Data East hardware, so I haven't been able to fully investigate this.

As a result, these games are still "unsupported". :(


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 Post subject: Re: Dexter and Data East boards?
PostPosted: Fri Jun 14, 2019 6:37 pm 
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Warren Ondras wrote:
Hi!

The basic problem is that the Data East hardware for Begas/Cobra/Road Blaster requires the laserdisc player to sync its video to the graphics output of the main PCB, instead of the other way around as most games do. The video output from the Raspberry Pi can't be synced to an external source, so Dexter is unable to support these games.

There is still some hope, though. I have heard tell of a mod for these games that allows them to work with an LDP-1450 instead of the usual LDP-1000A. The 1450 doesn't have a sync input, so if the game can be changed to work with a 1450, it should work with Dexter as well.

Unfortunately, I have been trying for some time to get actual details about this mod, without success. I have a few theories about how it could be done, but I don't have complete Data East hardware, so I haven't been able to fully investigate this.

As a result, these games are still "unsupported". :(


I don't know if this helps, but I have a Cobra Command board that is on the Data East dedicated set, but it has an unknown data east top board that most likely converts it to work on a different laserdisc player. Maybe there is a hint in the rom on the top of the board?

https://www.dropbox.com/s/k39as10506f13 ... .jpg?raw=1

The rom on the top board:
https://www.dropbox.com/s/7x0qziyp53tqt ... .bin?raw=1 (2764)

Maybe this could help?


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 Post subject: Re: Dexter and Data East boards?
PostPosted: Sun Jun 23, 2019 2:04 am 
DAPHNE Team
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Posts: 295
Wow, that's wild! I had never seen or heard of this board before.

The "CN5" port looks very much like an LD-V1000 connector. It's the same as the one on the single-board version of Cobra Command for conversions, and the 74LS374 chips next to it would be appropriate for interfacing with an LD-V1000. Interesting that it also has an unpopulated space for a DB25 port, which would presumably be RS232 (the two small unpopulated ICs next to it would be level translators).

The big question is what it does for video sync. I'm pretty sure the Sony chip is a CX773 sync generator. I can't find a datasheet for it, but I'm guessing it has the ability to lock to an incoming video signal, in which case it would be replacing/overriding the existing sync on the main PCB with one that is locked to the LD ideo. The board has a 50-pin connector to attach it to the main game PC; I guess the next step would be to figure out what it's connecting to and what signals it is affecting.

It's all still a bit of a mystery, but this is the first real clue we've had, so thanks for sharing!


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 Post subject: Re: Dexter and Data East boards?
PostPosted: Mon Jun 24, 2019 7:18 pm 
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Warren Ondras wrote:
Wow, that's wild! I had never seen or heard of this board before.

The "CN5" port looks very much like an LD-V1000 connector. It's the same as the one on the single-board version of Cobra Command for conversions, and the 74LS374 chips next to it would be appropriate for interfacing with an LD-V1000. Interesting that it also has an unpopulated space for a DB25 port, which would presumably be RS232 (the two small unpopulated ICs next to it would be level translators).

The big question is what it does for video sync. I'm pretty sure the Sony chip is a CX773 sync generator. I can't find a datasheet for it, but I'm guessing it has the ability to lock to an incoming video signal, in which case it would be replacing/overriding the existing sync on the main PCB with one that is locked to the LD ideo. The board has a 50-pin connector to attach it to the main game PC; I guess the next step would be to figure out what it's connecting to and what signals it is affecting.

It's all still a bit of a mystery, but this is the first real clue we've had, so thanks for sharing!


Let me know if you would like to borrow this...maybe it could help with supporting the data east boards in the future?


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