Dexter Posted March 5, 2015 Share Posted March 5, 2015 Hello galls and guys, First off, it seems that this is THE place to be for information and reliving the TI-99/4A. Thanks for that! As a child, about 13 years young, I had a TI-99/4A, TI Extended BASIC and a portable cassette player / recorder. With that combination I had years of fun with only the standard documentation that came with it. Now that I saw this video which forces me to get back a TI-99/4A with TI Extended BASIC. https://www.youtube.com/watch?v=yAOlEImLGx0 I learned he’s also a member of this forum. Great video, and thanks for the nostalgia!!! Here in Europe / Netherlands, it’s rather expensive to get just a plain TI-99/4A. However, I’m in the process of obtaining a slightly defective TI-99/4A in a nice condition for €40,00 including shipping. In 1986, I bought a Commodore 64, on which I learned a lot about assembler and electronics. I’ve been a C64 fan and collector from 1996 till today, so the challenge of repairing the TI-99/4A is about the lack of knowledge about the machine and having no spare parts for it. I’m kind of hoping it’s just a memory chip which needs to be replaced. But firs, I’ll have to see if I can obtain the machine, and get it home safely. Regards, Marco 2 Quote Link to comment Share on other sites More sharing options...
TheMole Posted March 5, 2015 Share Posted March 5, 2015 (edited) It is, it's broken video ram. They can be replaced, if you can source the chips. Another alternative (albeit more expensive) is installing an F18A video chip. This gives you the ability to connect your TI to a VGA monitor, has some nice added features (more colors, more video modes, less sprite limitations, smooth scrolling backgrounds, ...). *edit* Oh, and welcome to the community, I'm sure you'll like it here! Edited March 5, 2015 by TheMole 1 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted March 5, 2015 Share Posted March 5, 2015 Interesting GROM 0 in that one too--the German "BITTE DRUECKEN SIE EINE TASTE" isn't one I've seen before (and I was in Germany for about 10 years right after TI pulled out of the market). You may just need to reseat the socketed ROM/GROM chips--or you may have a bad RAM chip, with the most likely cause (about 95% chance) of your problem being the RAM chip. They are relatively easy to obtain and if you are good at soldering, easy to replace too. Note also that the TIGG is still very active in Holland (and I think their spring regional meeting is pretty soon too), so you have a local support option too. 3 Quote Link to comment Share on other sites More sharing options...
CosmicBoy Posted March 5, 2015 Share Posted March 5, 2015 Note also that the TIGG is still very active in Holland (and I think their spring regional meeting is pretty soon too), so you have a local support option too. Their website can be found here http://www.ti-99.nl/ Quote Link to comment Share on other sites More sharing options...
Willsy Posted March 5, 2015 Share Posted March 5, 2015 Welcome to the group! Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 5, 2015 Share Posted March 5, 2015 Could it be that a German cartridge is plugged in, like "Schachmeister" (Video Chess, German edition)? These cartridges are able to replace the Master Title Screen. Another indication for that is that it calls itself "TI-99/4". Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 5, 2015 Author Share Posted March 5, 2015 @all Thanks for the warm welcome, I like it already here! The deal is on! I bought the TI-99/4A mentioned above. Here are some pictures what’s included. Are there some good schematics or service manuals for the TI-99/4A on the net? @TheMole It is, it's broken video ram. They can be replaced That sounds reassuring! I have a very bad low resolution schematic from the internet, but I can see they are 4116 16k x 1bit. Unfortunately, I don’t have them in stock. I have a few 41464 64k x 4bit DRAM’s, which can be found on old VGA cards. The F18A looks like a great add-on. @Ksarul I don’t know anything of the GROM concept yet. Indeed, I will reseat all socketed IC’s and probably replace some electrolytic capacitors. @mizapf Yes, it’s the module “Schachmeister”, it’s the only module included. A pitty that it isn’t TI Extended BASIC. Now I have to wait untill it arrives, and cross my fingers that it's just bat contacts. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted March 5, 2015 Share Posted March 5, 2015 The Schachmeister cartridge is what was changing the screen, so it would be a standard GROM 0 in the console. On the problem, it is almost guaranteed to be the RAM chips. There is a complete troubleshooting guide for the TI console out there (I just recently dug up my copy for the 99/4 console to help someone with a problem on a /4 (not the /4A you have)). I'm pretty sure it is up on the WHTech FTP site. This manual has some better schematics: Console and Peripheral Expansion System Technical Data.pdf Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 5, 2015 Share Posted March 5, 2015 Remember our tests some months ago? http://atariage.com/forums/topic/231506-having-problems-with-my-new-ti-99/?p=3108200 Try to start up the console without Schachmeister and compare it with those screenshots. Quote Link to comment Share on other sites More sharing options...
Stuart Posted March 5, 2015 Share Posted March 5, 2015 (edited) Looking at the colour bars, it's a perfect match for the first of those screenshots, Michael. There - I told you they would be useful. The screenshot name is "vram 7f" - so which bit is 'stuck'? Edited March 5, 2015 by Stuart Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 5, 2015 Share Posted March 5, 2015 Right, we don't need the original title screen. 7f means that the most significant bit is stuck to 0. From the schematics I would say this is U109; in the "Technical Data" document, this is the rightmost 4116 circuit; see http://www.mainbyte.com/ti99/hardware/chips/main_board_big.html Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 6, 2015 Author Share Posted March 6, 2015 This manual has some better schematics: Console and Peripheral Expansion System Technical Data.pdf Great! This is way better than the ones I had in gif format. Remember our tests some months ago? http://atariage.com/forums/topic/231506-having-problems-with-my-new-ti-99/?p=3108200 Try to start up the console without Schachmeister and compare it with those screenshots. Well, this makes it possible to determine the failure even before I have the console at home. :-) The picture named *7F* looks most like the failure my console has, which indicates a faulty MSB. That should correspond with U109 on page 19 from the manual above! What can I say, that's marvelous!!! I've looked on eBay to find some 4116 RAM's but I'm not sure if I should go for them. I have good experience with Utsource, however, it will take a while till they arrive. Does anyone has one or two in stock, which I could buy. Either I could buy them from Utsource and return some to you or whatever else. Anyway, I'm very happy that all turns out so well! Quote Link to comment Share on other sites More sharing options...
+Schmitzi Posted March 6, 2015 Share Posted March 6, 2015 I am not sure for the RAMs but a look is worth on arcadeshopper.com in the TI-99-section Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 6, 2015 Share Posted March 6, 2015 There are 16 of them on a 32K memory expansion card. Maybe it would be easier to look out for those. Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 6, 2015 Author Share Posted March 6, 2015 @schmitzi arcadeshopper.com rocks, super! @mizapf I’ll look into that, maybe I can use a 41464 somehow. I briefly looked at the UBERgrom board and video, I guess this will be the first “modern” device I’ll order for the TI. 1 Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 13, 2015 Author Share Posted March 13, 2015 Indeed, U109 was defective. I could feel that it was a bit warmer than the others. I replaced it with a commodore DRAM 64k x 1bit. The information can be found here: http://www.c64-wiki.com/index.php/RAM#DRAM 4116 16 K x 1 DRAM. Needs −5, +5 and +12 volt power supply. +---+--+---+ VEE |1 +--+ 16| GND D |2 15| CAS WE |3 14| Q RAS |4 4116 13| A6 A0 |5 12| A3 A2 |6 11| A4 A1 |7 10| A5 VDD |8 9| VCC +----------+ How to use a 4164 chip instead the original 4116: Bend pin 1 und 8 upwards so they no longer go into the socket's connectors. Connect Pin 8 and 9 with one another through a short piece of wire. Make sure pin 1 and 8 are not in contact with any other components nearby. Insert the chip like this into the socket. 4164 64 K x 1 DRAM. +---+--+---+ |1 +--+ 16| GND D |2 15| CAS WE |3 14| Q RAS |4 4164 13| A6 A0 |5 12| A3 A2 |6 11| A4 A1 |7 10| A5 VCC |8 9| A7 +----------+ If you need one of the 4164 chips, you can also use a 41256 instead. You have to solder a short piece of wire between pins 1 and 16 of that chip (these are the pins just left and right of the alignment notch on the chip). This mod will make the chip look just like a '64 chip to the system. 4464 64 K x 4 DRAM. +---+--+---+ OE |1 +--+ 18| GND D0 |2 17| D3 D1 |3 16| CAS WE |4 15| D2 RAS|5 4464 14| A0 A6 |6 13| A1 A5 |7 12| A2 A4 |8 11| A3 VCC |9 10| A7 +----------+ I also did the modulator mod from this page: http://www.ti99.com/ti99r1.htm Furthermore a · nanoPEB v1 is on its way, and I’ve ordered an · Extended Basic v2.7 Suite Cartridge, which looks lovely on the pictures. After cleaning: After repair: 2 Quote Link to comment Share on other sites More sharing options...
UKRetrogamer Posted March 13, 2015 Share Posted March 13, 2015 Well done. The Ti is a nice machine with a thriving community, here on AtariAge. And a nice restoration. How did you manage to change the language to English? Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 13, 2015 Author Share Posted March 13, 2015 Thanks, I didn’t realize that the TI community is growing. On the other hand, the Commodore scene does too now. I guess retro is in. The console on itself is always in English, when I plug in the Schachmeister module, it’s showing German text. On the picture I have plugged in an Extended BASIC cartridge, which was one of the reasons I wanted the machine back. A very nice member here on the forum made that happen. \o/ Quote Link to comment Share on other sites More sharing options...
UKRetrogamer Posted March 13, 2015 Share Posted March 13, 2015 (edited) Yeah, the XB 2.7 cart is a work of genius. If you have access to an EPROM programmer, you might also wish to get hold of some of the 512K cartridge boards and compatible EPROMs. There are 5 (soon to be 6) ROM images elsewhere in the forums containing the best of the Ti game library in menu format. Rasmus has released his excellent home-brew games in ROM format too, so an EPROM programmer is a good investment if you would like access to a growing catalog of software. Edited March 13, 2015 by UKRetrogamer Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 13, 2015 Author Share Posted March 13, 2015 Thanks for the tip. Indeed, I forgot to mention that I included a red board in my order. Yes, a not too expensive EPROM programmer would be a good idea. I have a few programmers for the C64, but the maximum I can burn is 64 KiB. It's a pretty nice job they did. Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted March 13, 2015 Share Posted March 13, 2015 What specific programmer would you suggest a newb purchase? Do you have a good source for reliable chips? What kind of startup expense would I be looking at? Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 13, 2015 Author Share Posted March 13, 2015 Personally I’d like to buy a china programmer. I can’t afford a Galep 5 Some time ago the TOP853 USB was popular, but I read it only works reliably under WinXP. I think now the most popular one is the MINI PRO USB TL866A. All at eBay of course. That’s my research so far. The chips I could buy in Germany, they are certainly reliable, but expensive. The prices vary on the accessories you would want. Quote Link to comment Share on other sites More sharing options...
UKRetrogamer Posted March 13, 2015 Share Posted March 13, 2015 I bought a Mini Pro TL866CS from eBay on Gazoo's recommendation and it's worked well for everything I've used it for so far. This includes Ti 512K carts, the 632K carts (which also requires a PLCC32 adaptor, included in the "kit" I bought). I've also used it with other micro/EPROM projects and for copying Arduino (Atmel ATMega328) boot-loaders, saving me the hassle of having to use one Arduino to program another. What it WON'T program, are the EPROMs required by Ksarul's new 2048K carts as the Mini Pro doesn't have a long enough ZIF socket to accept the longer IC of the 2048K EPROM Ksarul chose. Quote Link to comment Share on other sites More sharing options...
Dexter Posted March 13, 2015 Author Share Posted March 13, 2015 That looks good, even the price is right! Quote Link to comment Share on other sites More sharing options...
+Lee Stewart Posted March 13, 2015 Share Posted March 13, 2015 I bought a Mini Pro TL866CS ... This one is great for everything except ICSP (In Circuit Serial Programming). For that, you need the TL866A. That looks good, even the price is right! ...and, the TL866A is usually only a few bucks more than the TL866CS. I think mine was $5 more when I bought it last year. ...lee Quote Link to comment Share on other sites More sharing options...
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