Tempest Posted January 2, 2010 Author Share Posted January 2, 2010 Hmm... Now I'm starting to wonder if it's the SIO mod that's the culprit. Remowilliams, does your system have the SIO mod? The SIO power mod? Yes. I would tend to think that wouldn't have much effect unless you were using an SIO powered device though. Note that the biggest change in higher cart reliability on mine is pulling out the 32in1... True, but who the heck knows? I'm just trying to narrow down the possible cause. So you think the 32 in 1 is the main problem? That's interesting, but if it's true then we have a problem since I need the 32 in 1. Does your system work with Congo Bongo on a cart? Tempest Quote Link to comment Share on other sites More sharing options...
Tempest Posted January 2, 2010 Author Share Posted January 2, 2010 Steve suggested that I try replacing the MMU he put in my 1200XL with a real Atari one from an 800XL (C061618). It sounds like he may have used a generic one which could be the problem. He says: The only chips involved with the cartridge select logic are the MMU and 74138 at U18, and only the MMU is replaced in your upgraded XL Anyone want to try this? I'll give it a shot later when I have time, but I need to open up my 800XL first. Tempest Quote Link to comment Share on other sites More sharing options...
+remowilliams Posted January 3, 2010 Share Posted January 3, 2010 Hmm, I don't have an extra 800XL MMU. On mine, the main memory, expansion memory, U18, CPU, PS voltage regulators were replaced and a new large filter cap installed. Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted March 30, 2012 Share Posted March 30, 2012 Bump, Okay I have a 1200XL that hates different cartridges as well.... something is afoot... I hadn't realized it as I loaded mostly everything thru disk and just started using carts with is.... steps taken replaced ram chips, replaced the IC's, sprayed the cart port with contact cleaner... it had the sio power done as well Quote Link to comment Share on other sites More sharing options...
Ransom Posted March 31, 2012 Share Posted March 31, 2012 Bob1200xl solved this problem a while back. I'm on my iPad so I don't have the link handy, but it involved the link to ground being too long for some carts. He ran a short wire from the ground pin on a chip to the ground line on the cartridge port and that fixed it. The problem can also occur if you stack carts on an 800xl, 130xe, and perhaps others. With the 1200xl it can happen with just one cart inserted, though. 1 Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted March 31, 2012 Share Posted March 31, 2012 There are two known failures with carts on 1200XLs - one is the ground path and the other is address glitches. In addition, there are a few more problems that have just come to my attention. Bob Quote Link to comment Share on other sites More sharing options...
Ransom Posted March 31, 2012 Share Posted March 31, 2012 More problems, eh? Sheesh. I sometimes wish I hadn't fallen in love with the 1200XL back when it was released. D'oh! For those interested, here's the thread I was thinking about. The specific post about the ground wire is post #89. Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted March 31, 2012 Share Posted March 31, 2012 Karateka and Summer Games carts are reported to fail, but I do not have (cannot find...) them on cart. I would guess that they are a sub-set of the grounding problem, but I can't test them. Bob Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted April 1, 2012 Share Posted April 1, 2012 wow, my buddy put a scope on it and that long ground path acts like an antenna for everything, lots of random looking dirty noise from everything in and around the Atari, some shielding helped it (aluminumfoil), but I am definately adding the shortened 22 ga. wire from pin 8 of the MMU and pin 1 of the CPU to pin B of the cart connector as suggested by Bob. We scoped the XE just for giggles and putting the shields back on helped clean up the XE a little. I remember a spirited debate about shielding being useless and to be thrown out not too many years ago, Now it seems I will be putting them back on my Ataris as I clearly see the difference on a scope. Truely amazing it worked as well as it did! Monday approaches... What fixes exist for address glitches? I figure since I am knee deep into It I might as well knock out whatever known problems there are while it's apart. I am interested in locating the shielding for the 1200xl if anyone has it.....seeing is believing so for me it's probably best to have it on. _Doc Quote Link to comment Share on other sites More sharing options...
Gunstar Posted April 1, 2012 Share Posted April 1, 2012 (edited) This is an interesting thread. I've no idea if my modded 1200XL has thes cartridge problems becuase I only have a few carts, and they are all 16K or less, which seem to be the ones that work ok. I had kept my shielding on my 1200XL, with just cutting out a couple of areas for the 32-n-1 and ram upgrades, but after my last mods I just left it off. I'll go ahead and refit the shield and put it back in place and also do this ground mod now, even though I don't have cartridges that don't work yet. I'm planning on getting a flashcart and some of the other new releases like Xenophobe, Space Harrier and Tempest Xtreem; does anyone have these and a modded 1200XL that can confirm if they work ok or not? I've got the ground mod covered on the MMU/CPU end, but can someone tell me which pin is "pin B" on the cartridge port? Edited April 1, 2012 by Gunstar Quote Link to comment Share on other sites More sharing options...
bandit Posted April 1, 2012 Share Posted April 1, 2012 This is an interesting thread. I've no idea if my modded 1200XL has thes cartridge problems becuase I only have a few carts, and they are all 16K or less, which seem to be the ones that work ok. I had kept my shielding on my 1200XL, with just cutting out a couple of areas for the 32-n-1 and ram upgrades, but after my last mods I just left it off. I'll go ahead and refit the shield and put it back in place and also do this ground mod now, even though I don't have cartridges that don't work yet. I'm planning on getting a flashcart and some of the other new releases like Xenophobe, Space Harrier and Tempest Xtreem; does anyone have these and a modded 1200XL that can confirm if they work ok or not? I've got the ground mod covered on the MMU/CPU end, but can someone tell me which pin is "pin B" on the cartridge port? Yes, the 2 games both work on my moded 1200XL 8meg cart for Space harrier and The Tempest extreem. Quote Link to comment Share on other sites More sharing options...
sloopy Posted April 1, 2012 Share Posted April 1, 2012 This is an interesting thread. I've no idea if my modded 1200XL has thes cartridge problems becuase I only have a few carts, and they are all 16K or less, which seem to be the ones that work ok. I had kept my shielding on my 1200XL, with just cutting out a couple of areas for the 32-n-1 and ram upgrades, but after my last mods I just left it off. I'll go ahead and refit the shield and put it back in place and also do this ground mod now, even though I don't have cartridges that don't work yet. I'm planning on getting a flashcart and some of the other new releases like Xenophobe, Space Harrier and Tempest Xtreem; does anyone have these and a modded 1200XL that can confirm if they work ok or not? I've got the ground mod covered on the MMU/CPU end, but can someone tell me which pin is "pin B" on the cartridge port? Pin 'B' is second one in from the back, on the top... when you are looking at a cart face it will be the second from the right facing you... lettered pins are on the front, numbered on the back, and are inc'd via socket reference... sloopy. Quote Link to comment Share on other sites More sharing options...
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