fluxit

After sitting unused for a week, the Gemini's verboten Grand Prix cart shows only a black screen(like an empty slot) on the Gemini. Shimming the offending cart gives me varying color combinations of vertical stripes, but the game never loads beyond stripes. Meanwhile, an Ebay Stampede cart that I repaired recently, works every time. It has a chunk taken out of the cart case, and had a broken alignment peg and screw boss.

Try turning up the sensitivity on Food Fight arcade.

As was suggested elsewhere, using a .pro file compatible with the included version of Stella is probably the most likely way to successfully apply a configuration to a single rom. I just discovered a couple of potentially useless pieces of info while playing around with a keyboard plugged into the GsP. It runs miniGUI on Linux, you can pop up the task switcher with Ctrl-Esc while in the normal main game menu. You can also logout to the "Loading..." screen with Ctrl-Alt-Backspace, but the system doesn't reload the menu unless you power off and back on. Stella seems to have keyboard input completely disabled. No hotkeys work that I could find.

It looks like a homemade analog multimeter, with a digital multimeter glued to it. There probably aren't any 2600 guts in that case.

What type of controller isn't working? Is it just an Atari 2600 compatible stick in the right front port? Does the controller work for other games as the stick for player 2? Both players in Cannonhead Clash(NTSC) work fine here on my R77(Stella 6.6) with a Flashback 2600 stick and a Trooper stick.

Having acquired one of those 'half-priced' GsP(used,) I can confirm that controllers shipped with one unit will automatically pair wirelessly with another unit. However, a GsP will apparently only wirelessly pair with 2 joysticks simultaneously. The others will just endlessly blink their sync lights until you turn off a controller that has already paired. 4 player Warlords arcade does work with 2 GsP sticks wireless, and 2 wired. I don't normally consider myself lucky when I receive a used product with alkaline batteries already installed, but in this case, it saved me having to buy or scrounge up those 8 extra AAs.🙂

Do you have anything specific in mind? Overall compatibility seems to be pretty good from what I've seen so far.

What I don't understand is the consistency. I've measured with a caliper. Both carts are 11mm from the cart edge to the pcb. 1 mm from the pcb edge to the contacts. Those are the same measurements that I get for Atari, and Spectravision carts as well. Activision contacts do seem to be of worse quality, however, and do not tend to clean as easily as other carts. FWIW, I have tried backing the carts off by about a millimeter when inserted, and it seems to either make no difference, or make the problem worse(black screen.) Again, Grand Prix is the *only* cart that does this.

I just tested this here, and agree that there seems to be no difference. With the joystick held to the right, it takes ~3 seconds to collide with an object after it enters the screen from the right. With the joystick held left, collision takes ~6 seconds. Centered is ~4 seconds till collision. This is true regardless of difficulty switch settings. The second course(hard) seems to increase the speed overall, but once again- it does this with no obvious effect from the switch settings. I wonder if there's a prototype out there somewhere that does use the second switch for speed.

Grand Prix. A simple, but entertaining racing game by Activision for the Atari 2600. It boasts convincingly detailed, brightly colored cars, and a sense of speed that seems almost excessive for the amount of track that is visible. So much as a gentle bump to another car results in one of the most violent displays that can be found in any game. Without learning the non-random patterns of cars, a few minutes of fun can be had by a single player by determining how much speed is safe before one ends up smacking into the rear of that slower car that you couldn't have seen in time. Competition between friends for best times can be quite enjoyable as you learn the patterns by heart, and go for that elusive perfect race. Where's the mystery? Well, I'd never actually had a personal copy of Grand Prix back in the day. I'd only ever played it with friends up until having mislayed one of my favorites by Activision- Megamania, about 10 years ago. Checking on Ebay, I found that the cheapest deal for an okay quality Megamania was in a listing that included 4 loose Activision carts, including Grand Prix. After a thorough cleaning, all four cartridges played just fine on my 7800. Moving forward in time to 2 weeks ago, I was missing my original Coleco Gemini from my youth, which I had reduced to components some 20 years past after a modification gone wrong. I found a good looking "for parts or repair" Gemini on Ebay for a nice price, and after a good cleaning and a small amount of adjustment, the Gemini was working well at scratching that nostalgia itch. It played virtually every cart the first time, every time. That is, until I tried Grand Prix. A pinkish red screen with greyish bars was the result on the Gemini with Grand Prix. Very occasionally, I'd have a black, rolling screen with grey shaded, moving blips. I cleaned the cart's contacts again... no change. After several cleanings with still no proper display from Grand Prix on the Gemini, I began to think that perhaps the cart was due for repair, or perhaps the ROM had died in the years since it had last been played successfully. I switched back to my 7800, and Grand Prix fired right up, and played perfectly. Reinserting the cart in the 7800, it again started properly with no special care. Had the cart fixed itself? Switching back to the Gemini, there was still just a pinkish red screen with greyish bars instead of the race track. No amount of reinsertions(switching off the power, of course) would ever load the game properly. In spite of the fact that *every* other cart I have out of storage at the moment, some 27 carts, including other Activision carts will load properly, and usually with a single insertion, the Gemini's contacts did have a very gentle grip on the carts, so I decided to remedy that. Removing the rivets holding the cart guide to the board freed the guide, so that I could easily(gently, and carefully) increase the tension applied by the Gemini's contacts. I replaced the rivets with low profile hex head M3 screws, loctite, nuts, and fiber washers to protect the PCB. Trying a few of the games that had previously worked on the Gemini showed good results. They still played fine, and now the console had a positive grip on the cart that offered some resistance when removing them from the slot. The moment of truth had come. I inserted Grand Prix, and turned the power switch to on. The result was unchanged. I was greeted by yet another pinkish red screen with greyish bars. It couldn't be true. Was this cart actually incompatible with my Gemini? A couple of web and Atariage searches turned up no definitive results regarding Gemini game compatibility problems. I decided to try another Grand Prix cart, as another similar quality cart could be had for $7 shipped. A week later the filthy new cart arrived, and after a good cleaning, I inserted it into the Gemini and flipped the switch, to be greeted by... a proper Grand Prix game screen. Switching back to the 7800 with the newly acquired Grand Prix cartridge, there was to be found... a pinkish red screen, with grey bars. A reinsertion on the 7800 showed the same. I switched back to the original cart on the 7800, and the game fired right up. TLDR; the mystery is that I have 2 Grand Prix carts. For my real consoles, one cart only works on the 7800. The other cart only works on the Gemini. Seemingly, no amount of cleaning or reinsertions will ever change this. Both carts work perfectly on my Retron 77, and checked out as having the same ROM on the R77.

Unfortunately not. When Space Rocks is set to gamepad mode, it acts as though the second button is triggered continuously. Scramble acts as though you have a 1 button controller, so Stella is not configured for the extra buttons. The console switches are mapped to start and select on the controller, with the rest being accessible through the pause menu.

Are you sure that the cart slot is in good shape? Dirty, lose or damaged contacts can cause those symptoms.

I've seen something similar on the Retron 77 with a bad HDMI cable.

Out of curiosity, and considering the current situation with the 2600+ regarding PAL 7800 cart compatibility, I tried the PAL 7800 original releases on the GsP. The GsP must be using a similar build of the ProSystem emulator, because it has the same issues with PAL roms that the 2600+ has with PAL carts.

Oops. It must have been a glitch when I couldn't page back and forth with left and right. I know I tried it at least once when it didn't work, probably twice. I glad that it *does* actually work already- at least some of the time.😁

I was surprised with how well 4-way joystick games work on the GsP's joystick. Frogger is great on it. Speaking of great games to play on the GsP, Amoeba Jump works perfectly.

The demos of Elevator Agent and Turbo Arcade didn't work. Hopefully the promised firmware update will give us paging support in the SD card browser using left and right on the stick. An attached keyboard works for directional inputs, but unfortunately pageup and pagedown don't work.

Actually, it's apparently running a relatively recent build. Space Rocks works. Scramble works.

By accident today, I discovered that if you want to return to the built-in games list from the SD cart games list, you just have to press the home button on the console. The controller home button only returns you to the SD card list, if you have selected it after booting, it will not return you to the built in games.

I was going try this next, but it turns out that the GsP just doesn't like .zip files created using the gui archive tool of Linux Mint Cinnamon. A freshly rezipped from the gui, known working Zaxxon art pack was ignored by the GsP. When I created the zip from the command line instead, it works fine on the GsP. Thanks for the help in ruling things out. It should be smooth sailing from here.

2600-acid drop.a26, though I'm not sure if the GsP likes for there to be spaces in file names.

I appreciate the details. Yeah, I considered and tested for all of those possibilities. I even compared a working .art file to one of my non-working edits with a hex editor to make sure that something strange wasn't being added that I didn't see, and that the proper carriage returns were in there(if necessary.) There were no differences, other than my edits. At this point I'm thinking it probably actually is something .zip related that the GsP's MAME doesn't like. I'm going to try freshly zipping from the command line, as previously I was using my OS's gui zip tools to update the files in the zip I was working on. The resulting files *look* and test fine on my computer, and I've never had a problem like this before, but I don't have any other ideas at this point. I guess to rule out the .zip being the problem, I can take a working set and just rezip it, to see if I can cause it to fail with no actual edits having been done to the included files.

I'm stumped. I tried to down-convert some art from my current MAME. I thought that by creating the 2 color mask PNG + RGB PNG, and using a known working .art file, altered to point to the new images, that the game would at least show *something*, but I was wrong. It just ignores the art. I tried different resolutions. I tried just tweaking the .art file of a working set, without altering the original(to the download set) images at all, but even if I just alter the last digit of a couple of numbers in the .art, the GsP refuses to load the resulting set.

Those are the gates in the n7404a ic. The one with the blue dot.

Having just retensioned the slot contacts on my 'new' Coleco Gemini, I've come to the conclusion that the Activision cart problem is more than just thinner PCBs(though some are definitely thinner than Atari's.) I believe that Activision carts tend to have inferior contacts on them as well.