SoundGammon Posted April 26, 2019 Share Posted April 26, 2019 I have a 7800 OS with Asteroids built in that I pulled from a 7800 I got from Australia, PAL, a while back and I want to put it in my custom 7800. What I need is the diagram of the change, jumper and wiring for the support chip that needs to be installed! Thanks. Rob Quote Link to comment Share on other sites More sharing options...
+Mitch Posted April 26, 2019 Share Posted April 26, 2019 Are you putting it in an NTSC 7800? Mitch Quote Link to comment Share on other sites More sharing options...
SoundGammon Posted April 26, 2019 Author Share Posted April 26, 2019 Yep! It'll work! Quote Link to comment Share on other sites More sharing options...
Shawn Posted April 26, 2019 Share Posted April 26, 2019 Move the jumper from W0 to W1 and you are good to go. Quote Link to comment Share on other sites More sharing options...
SoundGammon Posted April 27, 2019 Author Share Posted April 27, 2019 Thanks! Now I have to order some sockets! Quote Link to comment Share on other sites More sharing options...
PacManPlus Posted April 27, 2019 Share Posted April 27, 2019 Is there an NTSC version of the BIOS that contains Asteroids... and doesn't do the initial check? Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted April 27, 2019 Share Posted April 27, 2019 PMP I believe the standard Euro bios still still work on NTSC and it doesn't do the encryption check. Best I think even sells it as a kit with instructions for doing it. 1 Quote Link to comment Share on other sites More sharing options...
+Mitch Posted April 27, 2019 Share Posted April 27, 2019 The Asteroids BIOS is universal and was designed to work in either PAL or NTSC 7800s. Apparently Atari was planning on shipping it in NTSC 7800s at one point but it never happened. There is a prototype ROM of the Asteroids BIOS that is NTSC only. Mitch 3 Quote Link to comment Share on other sites More sharing options...
Trebor Posted April 27, 2019 Share Posted April 27, 2019 The prototype ROM of the Asteroids BIOS that is NTSC only is included as part of the bulk BIOS archive for the A7800 emulator. It is the file"c300558-001a.u7" highlighted below: 3 Quote Link to comment Share on other sites More sharing options...
CPUWIZ Posted April 27, 2019 Share Posted April 27, 2019 Ha, speed_bios.bin. 2 Quote Link to comment Share on other sites More sharing options...
PacManPlus Posted April 28, 2019 Share Posted April 28, 2019 *does searches, looks at pictures of installation instructions... I may attempt this, but my 7800 board looks NOTHING like the pictures I've seen, especially the one above. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted April 28, 2019 Share Posted April 28, 2019 The prototype ROM of the Asteroids BIOS that is NTSC only is included as part of the bulk BIOS archive for the A7800 emulator. It is the file "c300558-001a.u7" highlighted below: A7800BIOS.PNG Looks like you are missing the Pole Position BIOS, the proto NTSC BIOS and the alternate highscore ROM. Mitch 1 Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted April 28, 2019 Share Posted April 28, 2019 *does searches, looks at pictures of installation instructions... I may attempt this, but my 7800 board looks NOTHING like the pictures I've seen, especially the one above. Then what does your 7800 board look like?! Because all the NTSC boards basically look the same layout wise. Only the extra timing stuff on the right middle changes as those are either populated or not in some cases. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted April 28, 2019 Share Posted April 28, 2019 Does it look more like this one? Quote Link to comment Share on other sites More sharing options...
Trebor Posted April 28, 2019 Share Posted April 28, 2019 Looks like you are missing the Pole Position BIOS, the proto NTSC BIOS and the alternate highscore ROM. Mitch Sorry, I didn't mean to imply the "bulk" BIOS archive for the A7800 emulator is all-inclusive. I believe the folder capture below covers the additional BIOS files you mentioned and some others. I think it has all the HSC ROM files also, or there might be a third one not in the folder. A couple of other files may be 'scattered' elsewhere too. I might have to snoop around in my folders and files. *Edit: Looking over that list, I spelled Asteroids incorrectly, or was that intentional. *Edit2: Nope...just a typo on my part. Quote Link to comment Share on other sites More sharing options...
fluxit Posted April 29, 2019 Share Posted April 29, 2019 Asterioids. Isn't the scientific name for 'Atari thumb?' Quote Link to comment Share on other sites More sharing options...
PacManPlus Posted April 29, 2019 Share Posted April 29, 2019 (edited) Does it look more like this one? Kind of, but still different. Mine has W3, W4, and W5 jumpers above and to the left of the color wheels. Give me a minute, I'll open it up again and take a picture. Edited April 29, 2019 by PacManPlus Quote Link to comment Share on other sites More sharing options...
PacManPlus Posted April 29, 2019 Share Posted April 29, 2019 Here's a close up of the section I was talking about. Notice the 'W3', 'W4', 'W5, & 'W6' jumpers left & above the color wheel. Haven't seen a picture with this one in it... Quote Link to comment Share on other sites More sharing options...
+Mitch Posted April 29, 2019 Share Posted April 29, 2019 Interesting, can you post a pic of the whole board? Mitch Quote Link to comment Share on other sites More sharing options...
TailChao Posted April 29, 2019 Share Posted April 29, 2019 Interesting, can you post a pic of the whole board?Seconded, I've never seen a board revision where a RAM chip's footprint supports 24 or 28 pin devices like this. Might be a really late one. Quote Link to comment Share on other sites More sharing options...
PacManPlus Posted April 29, 2019 Share Posted April 29, 2019 Sorry I didn't see this sooner... I'll post a pic when I get home. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted April 29, 2019 Share Posted April 29, 2019 Now, I need to dig though my pile of 7800s to see if I have one with this board. Mitch Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted April 29, 2019 Share Posted April 29, 2019 I think I've seen these boards before with the Goldstar ram chips in them but never really looked that closely. I do know I've seen them where that main ground rail in the middle cuts off at that cap at C22 instead of running further down the board. I guess since I've only ever had to focus on the video section of these, I've never noticed the extra jumpers etc. It is also doesn't have the silkscreen for the rarely installed 2nd 3904 tranny under the crystal that usually has a resistor shoved in there instead. Quote Link to comment Share on other sites More sharing options...
Shawn Posted April 29, 2019 Share Posted April 29, 2019 If I'm reading that board right it looks like it could handle a 28 pin SRAM on the bottom socket closest to the BIOS. I'm gonna guess that is what the other jumpers are for. Maybe W4 is the equal to W1 on the other board? I can't see all the traces to see if that goes to the high address on the 24 or 28 pin BIOS chip to know for sure. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted April 29, 2019 Share Posted April 29, 2019 Here's a close up of the section I was talking about. Notice the 'W3', 'W4', 'W5, & 'W6' jumpers left & above the color wheel. 20190428_220000.jpg Haven't seen a picture with this one in it... Interesting how many variants there are for such an "unsuccessful" system, eh? My second 7800 (and daily player) is an A1 serial number machine with an Expansion Port that has a similar layout, but not at all identical. Quote Link to comment Share on other sites More sharing options...
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