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shadowdoggie

How is it that all 3 of my Buck Rogers carts roll?

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I have three Buck Rogers carts, and all three of them roll on my TV as if they were PAL carts. The odds are really against this, since 99% of my other games are NTSC. Is there something about this game that I don't know? I've tried them on a Sears 6 switch, a Jr., and on a Vader system and they all roll.

 

Thoughts?

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The title screen for Buck Rogers is 240 lines. Most Atari games (NTSC) shoot for 262 lines. Your TV doesn't seem to like having too few scanlines, and that is why it is rolling.

 

 

Buck Rogers then jumps to 249 lines when it displays "Level 01" (after you press the firebutton). Finally, on the play screen it goes to a normal 262 scanlines.

 

 

See if your TV stops rolling when you get to the play screen.

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The title screen for Buck Rogers is 240 lines. Most Atari games (NTSC) shoot for 262 lines. Your TV doesn't seem to like having too few scanlines, and that is why it is rolling.

 

 

Buck Rogers then jumps to 249 lines when it displays "Level 01" (after you press the firebutton). Finally, on the play screen it goes to a normal 262 scanlines.

 

 

See if your TV stops rolling when you get to the play screen.

 

Wow! How in the world do you know these things? That's nutty. And by nutty, I mean impressive. Thanks for that info, they work fine once I get past "Level 01" (as you mentioned). Is there a list somewhere of other games where this may be an issue?

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If you use the Stella emulator, press ALT L to bring up a black info box. This will tell you the number of scanlines, type of bankswitching scheme, etc... To make it disappear just use ALT L again.

 

 

 

Off the top of my head I think Artillery Duel will give you problems. It suffers the same problem (too few scanlines).

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The title screen for Buck Rogers is 240 lines. Most Atari games (NTSC) shoot for 262 lines. Your TV doesn't seem to like having too few scanlines, and that is why it is rolling.

 

 

Buck Rogers then jumps to 249 lines when it displays "Level 01" (after you press the firebutton). Finally, on the play screen it goes to a normal 262 scanlines.

 

 

See if your TV stops rolling when you get to the play screen.

 

Wow! How in the world do you know these things? That's nutty. And by nutty, I mean impressive. Thanks for that info, they work fine once I get past "Level 01" (as you mentioned). Is there a list somewhere of other games where this may be an issue?

That's all Omega does all day - analyse Roms ;) :D

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Buck Rogers is hard to record to VCR as well. The playback is terrible.

 

I had issues with each of those games on my old Sony 34XBR960N set when I used my s-video modded system. Whereas my JVC 4:3 aspect ratio set runs everything great!

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Here's a hack I did that should run better on your TV's.

 

 

BuckRogers(BetterLineCount)NTSC.bin

 

 

It has a hiccup going from the title screen to the "level 01" screen, but otherwise it doesn't seem too bad.

 

 

If you are using Stella, make sure you highlight the rom, then go Options, Game Properties, Display, and change "Use Phosphor" to yes. Otherwise you'll have a bit of a flickerfest.

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Omega, is there a reason this cart does this? Was it sloppy programing on the part of Sega or a bug with writing it, contained in the code itself?

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Omega, is there a reason this cart does this? Was it sloppy programing on the part of Sega or a bug with writing it, contained in the code itself?

Just bad programming. The PAL version is short on scanlines too.

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While we're on the subject, why is level 10 displayed as 8C? That one has always bugged me since it should have been an easy bug to spot.

 

http://www.digitpress.com/eastereggs/26buckrogers.htm

 

8C is 140 decimal, but that doesn't make any sense.

 

Tempest

There was a bad compare instruction. If you look inside the rom with a hex editor you'll see digits for the left side, and the right side. These get OR'd together.

 

When the pointers get loaded for the level number, it wasn't getting compared to the right value. The pointers then point to the wrong area and you get "8C" instead of "10".

 

;loading pointers for level number
LF953:
   jsr    LF92F                 ; 6
   lda    $8F                   ; 3   get level number...
   lsr                          ; 2
   lsr                          ; 2
   cmp    #$0A                  ; 2   this should be #$09, #$09 will fix the bug.
   bcc    LF960                 ; 2³
   adc    #5                    ; 2   carry is set, so adding 6
LF960:
   clc                          ; 2
;code continues...

 

 

I also couldn't even get to level 2. I'm no great gamer. :( I noticed that the top bar bounces up and down on the black screen with the ships coming at you. This is like this in the original too. Just more bad programming.

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