acadiel

Thermal Printer block diagram and schematic - Feb (?) 1979 thermal_printer_1979.pdf

AtariAge might not like this one. It's gigantic. It's the TI-99/3B documentation from late 1980 (according to the dates on one of the later pages). This was a Z80 CPU Card to replace the TMS9900 on a cost reduced system. There are many timing diagrams, schematics, and more in this set. The date (early 1980) appears before the 99/4A came out, so like @Ksarul said - it was likely a contender for a cost reduced 99/4. ti993B-z80-documents-1980.pdf

We need to put the Hexbus sidecar ones on here too as soon as we figure them out.

Here ya go. I can scan the rest later, but here’s the cover.

Check this out, @iliketurtles

I have our GoFundMe up for the CB Wilson Document preservation that Ksarul and I have invested in. If you have the time or money, please consider donating - every bit counts. Regardless of what we raise, all of this will be scanned and placed on AtariAge and WHTech. Thanks so much!!! Go Fund Me Link

One more. This appears to be the final 99/4 schematics - January 1980. Next up - a huge collection of schematics dated August 1980 for the "99/3B" - no idea what they are, so will need the community to chime in. They're all in one huge set of docs, including a 99/3B Z80 CPU Card. ti99-4-jan-1980.pdf

Last one for the day... the second set of Feb 1979 documents. Again, stapled together and scanned in the order in which they were presented. tms9900_02-1979-second-prelim-set.pdf

This was a set dated 02-1979 that was stapled together. Note that there isn't a page 1-2-3-4 - they were scanned in the order that they were in the set. (The 2/79 is the date initialed on most of the pages in the lower right corner) tms9900_02-1979-prelim-set.pdf

And here we are back to Prod 156 (were they running two projects for the 99/4?) - January 1979. tms9900_prod156_01-1979.pdf

Here is the next schematic for the 99/4, dated 17 Oct 1978, although there are markings of other dates on it. This is marked as a 'preliminary' schematic. tms9900_prod227_10-1978-prelim.pdf

Here's the next schematic for the 99/4. @Ksarul - note this is now product 227, dated 13 September 1978. tms9900_prod227_09-1978.pdf

In also noticing that the schematic number stays the same too (for the most part.) It looks the schematic number is also a TI part number, just like the part numbers on the cart shells, etc.

Um, the UberGROM was in development for years before it was released. It was not built to be a multicart. Different hardware, different feature set, different audience, and the two devices shouldn’t be compared. signed, one of the three UberGROM designers

Yeah, it's large. It's a 1200 DPI A3 (11x17) scan. Even my i7 laptop chokes up a little when saving the PDF.

Both of them? Wonder if AA is doing something to the uploads. Grr...

It opens in Chrome for me fine - and on my Mac in Preview. Which program are you trying? Edit: Try this - it's a PDF/A instead of a PDF. See if it works. I'll try it on all my systems too. Schematic dated 5/8/1978. tms9985_1978_model_pdfa.pdf

I'll put all the TI-99/4(A) related documentation as I scan it in this thread. Working with @Ksarul to see how to best compile it, name it, upload it, etc. Some of these, I can't tell the dates. Some, I can, and some are bundled with others (folded together - so I guess I'll leave them scanned together.) Anyway, here's an image (and associated PDF) from my large format 11x17 A3 scanner (bought just to scan all this stuff). I give you the first test scan - early 1978, before it was called anything other than the "Home Computer Mainframe" - the TMS9985 8-bit home computer - the only such schematic in this entire collection about it. The whole PDF is below. Schematic dated 5/8/1978. Product 156.

I need one too, I don’t think I can deal with this membrane keyboard. Lol

Here's a test scan of the first (that I can tell) "Home Computer" schematic. May 1978, uses the TMS9985. Please download it and give me feedback on how readable it is, etc. (It's an 11x17 scan, so it's ginormous.) Edit: Tried attaching a PDF/A formatted one as well. Let me know what works in what and what doesn't work. tms9985_1978_model.pdf tms9985_1978_model_pdfa.pdf

I’ve done a rough sort. This is what I have so far in the file cabinet. I also have the following in binders: - TI-88 development Notes - Several Printouts of Wafertape DSR source code (2.5MHz and 3.58MHz - there is a third copy too in the development folder) - The TI-99/4 Morse Code Interface Box, TI Bug and GROM testing hardware schematics - A 1981 study commissioned to determine the market for an ALC (advanced language calculator) - CB’s notes binder

Thanks!! I’m splitting this with Jim too as it comes in. I have the file folders, file cabinet and large format scanner now - I’m just waiting on the scanner table and then I will get started.

Just in case people what to know which VRAM is which bit.... L is LSB (top right) and M is MSB (lower left.)

Yep, we figured out on Facebook that pin 25 RD7 goes to the upper right most chip. That’s our bad one. We probably want to make the same troubleshooting guide to show which chip is which bit.

Got my Pyuuta in today. Screen looks funny, reminds me of a TI VRAM issue. Might also try reseating the rom if it’s socketed. All the letters are off by one ASCII character, so maybe the LSB?