frdarryl Posted March 26, 2022 Share Posted March 26, 2022 Hi everyone, I've been having a strange, somewhat intermittent issue with my INTV System III unit. It was having graphics glitches, and swapping out the STIC fixed that. But I'm also having a strange, intermittent crashing problem. It seems that in certain (mainly old Mattel) games, when either I am about to enter the "game over" state (e.g. the enemies reach the bottom in Space Armada, or if I finish the ski hill in Skiing), the console will, randomly, completely freeze up. Sometimes the crowd sounds at the end of a ski run will continue while the screen goes blank. Other times it doesn't go blank or the sound turns garbled. And other times these games work completely as expected. But as far as I can tell, when these games crash, it seems that the game is about to jump from the end-state to a game-over-state, and that is interrupted somehow. So... I don't know much about the General Instruments architecture, but is it possible that perhaps there's a glitch when the code is jumping to a different memory vector somehow? Would that possibly be a RAM error? Or something with the glue logic on the bus? Or a CPU issue? For example, does Skiing jump to a certain vector at the bottom of the ski hill and somehow a certain bit on the bus is getting corrupted? (I'm trying to put on my EE hat but it's been a while!) I do have an extra (non-functional) Sears Super Video Arcade so I can try swapping chips, but I'm curious if anyone else has encountered this sort of problem or has ideas of what to try. Thanks! Quote Link to comment Share on other sites More sharing options...
walldog1 Posted March 26, 2022 Share Posted March 26, 2022 A person can actually finish a game? I have yet to accomplish this. I have never heard of this type of problem. I'll follow to see what feedback you get as this is very strange. If it is a programming thing, this rules out all the RAM chips I would think. Possibly one of the ROM chips? Or a problem that heat is bringing out (like a poor solder joint) since you would be playing quite a while I would think? FYI: You need to follow this thread to get email alerts. I learned this out the hard way. Quote Link to comment Share on other sites More sharing options...
frdarryl Posted March 26, 2022 Author Share Posted March 26, 2022 Thanks! I'm not sure if it's a programming thing so much as the program is possibly intersecting with a bad part of RAM (scratchpad RAM maybe, since the sound remains enabled??). I also saw an order of recommended chip replacement in the official Mattel repair manual that has the CPU as the first thing to try. So I'll probably do that first. However, I've possibly identified another pattern: If I complete a ski run in Skiing without crashing my player, it ends normally. But if I crash my player on the way down, then at the end of the hill the game crashes to a black screen and the crowd audio remains stuck. It's almost like some instruction is called at the end of the hill which is crashing. Or something is calling upon a certain part of RAM/ROM and is crashing. Or... who knows? I have another Skiing cartridge arriving in the coming days so I will test that one also. But since I'm having crashing with multiple games I don't hold out much hope for that. This might almost be enough to make me want to dive into learning more about the GI architecture! Quote Link to comment Share on other sites More sharing options...
mr_me Posted March 26, 2022 Share Posted March 26, 2022 The game does freeze when the Space Armada reaches the bottom, that's normal. Does the score appear? Other cartridges, besides Skiing, are also showing problems? Quote Link to comment Share on other sites More sharing options...
frdarryl Posted March 26, 2022 Author Share Posted March 26, 2022 39 minutes ago, mr_me said: The game does freeze when the Space Armada reaches the bottom, that's normal. Does the score appear? Other cartridges, besides Skiing, are also showing problems? Unfortunately there was no score shown, so Space Armada seems to have frozen just before that point. I've also experienced NHL Hockey freezing just after a goal was scored. So it seems pretty random, except for the case with the pattern I've seen in Skiing (which I will be able to test with a different cartridge next week). I've also tested with Auto Racing, Masters of the Universe, and Beauty and the Beast (for the sake of testing a non-Mattel game), and those appear to work flawlessly so far. Ahh, intermittent troubles: the most "fun" type of thing to troubleshoot! I suppose that trying to track this down is almost as much fun as playing the games... Part of me wonders if I should just break down and get a cheap oscilloscope so I can see what the bus is doing when it crashes. Quote Link to comment Share on other sites More sharing options...
IMBerzerk Posted March 27, 2022 Share Posted March 27, 2022 (edited) Did you try the easy stuff like cleaning everything? These things are 40+ years old and very sensitive to any kind of oxidation on the contacts. I just did the same for my Up N' Down arcade machine. Was having all sorts of graphic and sound issues. I just pushed in all the chips and it cleared the issues. Start there... re-seat any chips you can and make sure all the contacts to the connectors as well as the cart and cart port are as clean as you can get them. Edited March 27, 2022 by IMBerzerk Quote Link to comment Share on other sites More sharing options...
frdarryl Posted March 27, 2022 Author Share Posted March 27, 2022 16 hours ago, IMBerzerk said: Did you try the easy stuff like cleaning everything? These things are 40+ years old and very sensitive to any kind of oxidation on the contacts. I just did the same for my Up N' Down arcade machine. Was having all sorts of graphic and sound issues. I just pushed in all the chips and it cleared the issues. Start there... re-seat any chips you can and make sure all the contacts to the connectors as well as the cart and cart port are as clean as you can get them. Thanks! Yeah, I did clean the contacts, re-seated the socketed chips, and also re-flowed the solder on the board, as it looked like some of those joints may have not been all that great. I guess several decades can do a number on old electronics... Quote Link to comment Share on other sites More sharing options...
walldog1 Posted March 27, 2022 Share Posted March 27, 2022 3 minutes ago, frdarryl said: and also re-flowed the solder on the board, as it looked like some of those joints may have not been all that great. I guess several decades can do a number on old electronics... So you are telling us all is well now? If yes, great! I have actually been able to tell what angle the console was stored at (especially hot places) by the resin trails running from solder joint. And gravity also pulls on the solder over time.... I have held up many Logic Boards to a light and see a host of stars shining thru. Especially ground and power pins. And jumper wires. If a board's solder joints have a lot of bad ones, I will touch up every joint even though this is very tedious. I don't want a console I resell to fail for a "simple" thing. However, there are a few non accessible joints unless you were to pull every IC Chip off the LB. That was the fix for one of my boards..... I added sockets, tested continuity and for shorts on all tracings, reused same parts and it finally worked. I would also test and carefully look at PS board. It may also be close to causing future problems. Quote Link to comment Share on other sites More sharing options...
frdarryl Posted March 27, 2022 Author Share Posted March 27, 2022 Huzzah! I think I figured it out! I swapped the CPU for the one from a non-functioning Sears Super Video Arcade and the INTV seems to be running stably now! I'm going to have to play it a lot more to put it through it's paces (tough job, I know ??), but so far, so good. Along with the reflowed-solder and the cleaned contacts, hopefully this INTV runs for a long time to come. I also replaced the rapidly-disintegrating power supply ribbon cable with a wire-based ribbon cable. So far the caps all look fine on that board and the voltages are stable. Thanks for your suggestions, everyone! 2 Quote Link to comment Share on other sites More sharing options...
IMBerzerk Posted March 27, 2022 Share Posted March 27, 2022 Glad we can help! Nothing better than heard yet another Inty saved from the bone yard! Enjoy! Quote Link to comment Share on other sites More sharing options...
walldog1 Posted March 28, 2022 Share Posted March 28, 2022 3 hours ago, IMBerzerk said: Nothing better than heard yet another Inty saved from the bone yard! I have 5 INTV headed for scrap due to lack of 9600's. I need 6 currently. Rest of these units are all rebuilt. I know of someone who has 5, but they were are pushed into those static loaded Styrofoam board. The type where a small piece of the Stryrofoam is almost impossible to get off your body. I suspect static has killed these, but he wants $25 a piece untested! Quote Link to comment Share on other sites More sharing options...
frdarryl Posted March 29, 2022 Author Share Posted March 29, 2022 If anyone is interested (or in case it helps anyone with troubleshooting), I've written a blog post detailing my repair of this INTV unit. https://saskapriest.com/2022/03/29/repairing-the-intellivision-vintage-gaming-console/ 3 Quote Link to comment Share on other sites More sharing options...
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