xabin Posted March 24, 2019 Author Share Posted March 24, 2019 (edited) We don't have the tools to replace that chip, if it's soldered, but that seems to be the problem spot we're guessing, if we're getting no signal from the computer. We just took another look at the motherboard, and the video chip has a silver bar with 2 sockets glued into place on top of it with white stuff. We dunno why, but could that be causing part of the problem? Ours is this kind of motherboard: Edited March 25, 2019 by xabin Quote Link to comment Share on other sites More sharing options...
xabin Posted March 25, 2019 Author Share Posted March 25, 2019 One more thing: even after fixing a break in the connection to our RF modulator, when it's all plugged up and turned on, the light on the RF isn't coming on. I'm assuming that means that no signal is going through it? Quote Link to comment Share on other sites More sharing options...
Tursi Posted March 25, 2019 Share Posted March 25, 2019 We don't have the tools to replace that chip, if it's soldered, but that seems to be the problem spot we're guessing, if we're getting no signal from the computer. We just took another look at the motherboard, and the video chip has a silver bar with 2 sockets glued into place on top of it with white stuff. We dunno why, but could that be causing part of the problem? Ours is this kind of motherboard: The VDP is not soldered, so it's replaceable. The bar you are seeing is a heat sink, and the white stuff is heat sink compound. It's normal by now for that to be dried out, and overheated VDP chips do die. A replacement 9918A should not be too hard to come by, and you can use any modern heat sink compound on it. (Eventually the F18A replacement will be available again, which will allow an update to VGA output.) Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted March 25, 2019 Share Posted March 25, 2019 Definitely looking at the VDP at this point,but I also though that I would mention that Omega was very conservative in his estimate on the number of consoles some of us have. . .as I think I may have waaaay more than that, something like 50 of them. . .and that may be a serious underestimate. I may have a few spare 9918A chips lurking about that I received from one of the former TI managers a few years ago. Let me make some checks. 1 Quote Link to comment Share on other sites More sharing options...
xabin Posted March 25, 2019 Author Share Posted March 25, 2019 Definitely looking at the VDP at this point,but I also though that I would mention that Omega was very conservative in his estimate on the number of consoles some of us have. . .as I think I may have waaaay more than that, something like 50 of them. . .and that may be a serious underestimate. I may have a few spare 9918A chips lurking about that I received from one of the former TI managers a few years ago. Let me make some checks. Okay, thanks. If you find any that work, let us know, and we can negotiate a price for them. One more question: since we don't want to haul around an old CRT, we're wondering if we can use our flatscreen for the computer's display; it's an older style Vizio with composite and cable/antenna plugins as well as the standard HDMI and whatnot. 1 Quote Link to comment Share on other sites More sharing options...
Tursi Posted March 25, 2019 Share Posted March 25, 2019 Okay, thanks. If you find any that work, let us know, and we can negotiate a price for them. One more question: since we don't want to haul around an old CRT, we're wondering if we can use our flatscreen for the computer's display; it's an older style Vizio with composite and cable/antenna plugins as well as the standard HDMI and whatnot. Yes, the TI outputs composite video and audio through the rear port - have a look here: http://atariage.com/forums/topic/267621-ti99-4a-video-question/page-1?do=findComment&comment=3817130 If you don't want to build a cable, I think a few people here sell them. Quote Link to comment Share on other sites More sharing options...
xabin Posted March 25, 2019 Author Share Posted March 25, 2019 We bought a cable online, and we've got it sorted out, mostly, so we just need the chip and hope it works. Quote Link to comment Share on other sites More sharing options...
xabin Posted March 26, 2019 Author Share Posted March 26, 2019 Definitely looking at the VDP at this point,but I also though that I would mention that Omega was very conservative in his estimate on the number of consoles some of us have. . .as I think I may have waaaay more than that, something like 50 of them. . .and that may be a serious underestimate. I may have a few spare 9918A chips lurking about that I received from one of the former TI managers a few years ago. Let me make some checks. Hey. Were you able to find the chips? If so, how much would you want for them? Quote Link to comment Share on other sites More sharing options...
RickyDean Posted March 26, 2019 Share Posted March 26, 2019 Hey Xabin, I can do a swap, a good board for a bad, for 10.00 + shipping, will guarantee that it will work with your new PS, if the PS is good and will fit into the black and silver case. Let me know if this is acceptable. I can either repair the bad board or use it for parts, have a box full, that need to be fixed. PM me if interested. 1 Quote Link to comment Share on other sites More sharing options...
xabin Posted March 26, 2019 Author Share Posted March 26, 2019 Hey Xabin, I can do a swap, a good board for a bad, for 10.00 + shipping, will guarantee that it will work with your new PS, if the PS is good and will fit into the black and silver case. Let me know if this is acceptable. I can either repair the bad board or use it for parts, have a box full, that need to be fixed. PM me if interested. That doesn't sound bad. We'll discuss it, and let you know in a day or two. Thanks. 3 Quote Link to comment Share on other sites More sharing options...
xabin Posted March 27, 2019 Author Share Posted March 27, 2019 According to the article Flottmann1 linked, it looks like there's a possibility I'd need to replace one of the ROM chips, as well as the Video chip. I hope that's not the case; if it is, then we're likely going to take up RickyDean's offer for a replacement board, but we want to try just getting the video chip switched out and see if that has a difference. 2 Quote Link to comment Share on other sites More sharing options...
xabin Posted March 31, 2019 Author Share Posted March 31, 2019 if it were so easy, here's what https://www.nightfallcrew.com/22/06/2013/texas-instruments-ti-994a-diagnosing-and-fixing-motherboard-faults/ Well, thanks to FarmerPotato, we got a new chip, but it still isn't working. According to this, we'll also need to replace the ROM CD2156NL, but we don't want to take anyone else's generosity for granted, and since it's been in a barn for decades, we dunno if that's even going to fix it. Quote Link to comment Share on other sites More sharing options...
AwkwardPotato Posted March 31, 2019 Share Posted March 31, 2019 (edited) Just to be clear, you're getting static instead of video and no beep? The first thing I'd do is pull out the sound chip (should be labeled SN76489, SN94624, or similar) along with GROMs 1 & 2 (labeled CD2156 and CD2157 respectively). On your revision of the board these should all be socketed, and none of them are required to boot to the title screen. However, if any one of these fails, they can prevent the TI from starting correctly. Also, are you sure your replacement VDP is oriented in the socket correctly? Edited March 31, 2019 by AwkwardPotato Quote Link to comment Share on other sites More sharing options...
xabin Posted March 31, 2019 Author Share Posted March 31, 2019 Just to be clear, you're getting static instead of video and no beep? The first thing I'd do is pull out the sound chip (should be labeled SN76489, SN94624, or similar) along with GROMs 1 & 2 (labeled CD2156 and CD2157 respectively). On your revision of the board these should all be socketed, and none of them are required to boot to the title screen. However, if any one of these fails, they can prevent the TI from starting correctly. Also, are you sure your replacement VDP is oriented in the socket correctly? Sometimes it's black screen no beep, sometimes it's static, but we'll try your suggestion for the chips. And we made sure the VDP was inserted correctly, so that isn't it. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted March 31, 2019 Share Posted March 31, 2019 I may have a bare board that you can use to swap out the entire mother board. I got it as part of a lot of things I bought a few weeks ago. It was supposed to be a working machine, but the seller just threw everything into a box and shipped it with everything rattling around. It damaged the case and the keyboard beyond repair, but the board wasn't impacted. Let me know and I can put it into a box and mail it to you. That will get you past the random issues on that defective board. . . Quote Link to comment Share on other sites More sharing options...
xabin Posted March 31, 2019 Author Share Posted March 31, 2019 I may have a bare board that you can use to swap out the entire mother board. I got it as part of a lot of things I bought a few weeks ago. It was supposed to be a working machine, but the seller just threw everything into a box and shipped it with everything rattling around. It damaged the case and the keyboard beyond repair, but the board wasn't impacted. Let me know and I can put it into a box and mail it to you. That will get you past the random issues on that defective board. . . Erf, yoiu guys are just helping us make a refurbished TI, at this point, you know that, right? What would you like in exchange for it? Does it have the chips in it, or do we need to put the chips in? You said that the keyboard that came with it is damaged beyond repair; we could send you the one we had to replace on ours, since it's just a few keys that are sticking, and we dunno if it's still working or not. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted March 31, 2019 Share Posted March 31, 2019 I don't need anything for it. My wife will be happy because one of the 70 or so spare consoles I have in the house will be gone to a good home. . .she's trying to reclaim some of my hobby space for her own nefarious purposes. 1 Quote Link to comment Share on other sites More sharing options...
xabin Posted March 31, 2019 Author Share Posted March 31, 2019 (edited) I don't need anything for it. My wife will be happy because one of the 70 or so spare consoles I have in the house will be gone to a good home. . .she's trying to reclaim some of my hobby space for her own nefarious purposes. Okay... If you say so. I'll PM you with our address. Thanks for the offer, btw. I really wish we could repay everyone who helped us get the parts to repair this thing; we are now dedicated to getting it working, come hell or high water, to make sure your generosity isn't wasted. EDIT: Seems like you can't accept any new PMs. Thanks again for the offer. We're not sure what you mean by "bare board"; my boyfriend's dad has a soldering iron, but he doesn't really have the time or other equipment needed for soldering chips into a board. If it's ready to go, and just need a new VCD chip in it, we have that we can use. Our address is: Jeremy and David 3100 Frontage Road Apt. 38 Warsaw, IN 46580 Edited March 31, 2019 by xabin 1 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted March 31, 2019 Share Posted March 31, 2019 EDIT: Seems like you can't accept any new PMs. That happens. The fix is to either subscribe for more storage, or do some mailbox cleaning. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted March 31, 2019 Share Posted March 31, 2019 I'll have to clear out my mailbox again. . .and I'll get the board into the mail this week. Bare board is more to indicate that it is a fully-populated motherboard (no soldering or additional chips required) that is known to be working when I pop it into the mail. I want to see your machine up and working again too! Your location makes it a nice day trip to the Chicago Faire too (looks like a 2-3 hour drive each way). You'll meet quite a few of us in person if you do make it this fall, and there are always wonderful bargains to be had. . .in addition to all of the fun we have as a group doing hobby-related things. Everyone is welcome at da Faire! Quote Link to comment Share on other sites More sharing options...
xabin Posted March 31, 2019 Author Share Posted March 31, 2019 Thanks. We tried what AwkwardPotato suggested, just now, making sure to take out and reinsert the chips one at a time to test them by themselves, and we still got nowhere, so we're thinking the whole motherboard is fried, somehow (though we didn't plug in the keyboard, during the tests; should we have?), so the motherboard should work. We're grateful for this, and wish we could repay you guys. Quote Link to comment Share on other sites More sharing options...
xabin Posted April 1, 2019 Author Share Posted April 1, 2019 I'll have to clear out my mailbox again. . .and I'll get the board into the mail this week. Bare board is more to indicate that it is a fully-populated motherboard (no soldering or additional chips required) that is known to be working when I pop it into the mail. I want to see your machine up and working again too! Your location makes it a nice day trip to the Chicago Faire too (looks like a 2-3 hour drive each way). You'll meet quite a few of us in person if you do make it this fall, and there are always wonderful bargains to be had. . .in addition to all of the fun we have as a group doing hobby-related things. Everyone is welcome at da Faire! We have something similar to that in Fort Wayne; it's called Hamfest, and it's mainly for ham radio operators, but it also has (or had, it's gone downhill for a while) lots of old electronics for sale at good deals. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted April 1, 2019 Share Posted April 1, 2019 To give an idea how much fun Da Faire is for us, I drive there from the general vicinity of DC, others come from Florida and other somewhat distant parts of the US, and still others show up from Europe and even Australia. . .we are a global group of dedicated TI users. Hanfests can be a lot of fun too--there was even a sideport cartridge for the TI that let you connect it to a HAM radio. . .two hobbies in one! Quote Link to comment Share on other sites More sharing options...
atrax27407 Posted April 1, 2019 Share Posted April 1, 2019 Hamfests used to be a good source of electronics bits and pieces, Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted April 1, 2019 Share Posted April 1, 2019 To give an idea how much fun Da Faire is for us, I drive there from the general vicinity of DC, others come from Florida and other somewhat distant parts of the US, and still others show up from Europe and even Australia. . .we are a global group of dedicated TI users. 850 in da house, yo. Quote Link to comment Share on other sites More sharing options...
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