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Author Topic: "Odyssey 3" on Philips G7401  (Read 3619 times)
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Post Axe Pete!
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« on: October 26, 2017, 11:57:30 AM »

When testing the assembled Robot City cartridges, I discovered something funny.

My G7401 usually shows "Quel jeu?" after pressing the reset button. Sometimes, when I removed a cartridge and inserted another one, before pressing reset, the console showed "Odyssey 3" - see enclosed screenshot.

Maybe René can explain how this happens?
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« Reply #1 on: October 26, 2017, 01:18:39 PM »

Wow maybe I have an O3 after all  Cheesy
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« Reply #2 on: October 26, 2017, 01:27:34 PM »

 Cheesy
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Rene_G7400
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« Reply #3 on: October 27, 2017, 10:04:48 AM »

Maybe my Odyssey3 console contains a virus and copied it to the Eproms.
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« Reply #4 on: October 31, 2017, 09:17:24 AM »

So it seems nobody knows. A mystery ...

Could it be that the "Odyssey 3" text is in the G7400 BIOS because they ported it from the Odyssey 3 prototypes?
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Rene_G7400
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« Reply #5 on: October 31, 2017, 10:26:30 AM »

So it seems nobody knows. A mystery ...

Could it be that the "Odyssey 3" text is in the G7400 BIOS because they ported it from the Odyssey 3 prototypes?

I'm sure that the text "Odyssey 3" is not present in the BIOS of the G7400. Even on an Odyssey 3 console the '3' is not on the start-up screen.
But I did find the text "Odyssey 3" in the rom file of Robot City at address 1B60 !!!
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« Reply #6 on: October 31, 2017, 01:07:22 PM »

That is even more interesting!  Shocked

Why would they do that? Wasn't the game programmed in the UK?

When you play the demo on a G7000, the game enters "G7000" as high score holder.
When you play the demo on a G740x, the game enters "G7400" as high score holder.
So the game seems to check on which machine it runs on (Plus or not plus).

Would be interesting what happens when you play the demo on an Odyssey3 ...  Huh?
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« Reply #7 on: October 31, 2017, 01:42:57 PM »

G7400
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« Reply #8 on: October 31, 2017, 04:10:28 PM »

Thanks for checking!

Still weird why there is the "Odyssey 3" phrase in the game's code ...
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« Reply #9 on: October 31, 2017, 09:21:16 PM »


But I did find the text "Odyssey 3" in the rom file of Robot City at address 1B60 !!!

Wow. This is very interesting. Teria a Philips Norte Americana encomendado jogos da Europa Huh? Huh?
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Rene_G7400
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« Reply #10 on: November 03, 2017, 05:38:09 PM »

OK, I've been digging in the disassembly of this game, and I think I've found it: apparently you can stop the game by pressing the ENTER key. If you play this game on a console with Plus graphics you should see the Odyssey 3 screen then, except that they've forgotten to enable the Plus graphics access before writing the text to the screen. I know that in an earlier version of the Odyssey 3 console the access to the Plus graphics chip was done in a different way, so it might have worked then. (Technical detail: in an earlier version of the Odyssey 3 console the access to the Plus graphics chip was not done by enabling P15, but by disabling P12, P13 and P14.)
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« Reply #11 on: November 03, 2017, 08:48:53 PM »

OK, I've been digging in the disassembly of this game, and I think I've found it: apparently you can stop the game by pressing the ENTER key.

Great info. I tested it, so pressing enter you go to Select Game screen, but you´ll keep the highscore even if you chose another maze.
Pressing reset you clean the highscore!
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« Reply #12 on: November 03, 2017, 11:30:50 PM »

Great discovery, thanks for looking René!

And now I know that I was not drunken at Eurocon (well at least not in this particular situation) - Stephan Freundorfer played Robot City and had a high score, Matt Allen entered "Stephen" as high score holder for him. Some minutes later I saw the Select Game screen from the distance and thought "What a pity, now Stephan's high score is gone". Again some minutes later I saw Matt playing and suddenly Stephan's high score was back - after the Game Select screen! This was weird, and I kept thinking about it over the next days. Now I know why - after entering Stephan's name, Matt pressed the Enter key!!  Cheesy
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« Reply #13 on: November 04, 2017, 10:53:00 AM »

 Cheesy

Shame that it is discovered too late to put it in the manual. Oh well, let's consider it an easter egg  Wink
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