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Here are some examples of my modified GRAM0...



This takes the place of the Rainbow opening screen. Note the year - That's when I did it.



Second screen "MENU".



This shows the lower case character set - it is in Console Basic and Extended Basic - Don't know about anything else - I assume so because it's in GRAM0.







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Based on the Description, what he had was probably one of the aluminum pizza-box GSIM devices. More questions--and a picture of one of the devices we already have within the community, would probably fully clarify the matter (or send us on a hunt for another new TI-Internal device).



Corrected tidbit from DC about the GSIM device:


Jon, I need to correct a factoid. I remembered that Craig borrowed the TI development set from someone (?) and we only had it for a brief period on time. It didn’t own it nor did he pass it on to one of us. I’ll do my best to give you as accurate accounts as I can but, the thirty years passing makes it hazy sometimes. As I go through things I do recall more and more.

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Good things come to those who wait. Enclosed are all the development notes (handwritten, mostly) on the Gram Kracker. Note what I included and did not include, below. There are still some other items to scan, and I apologize for it taking so long. I have a very painful arthritic condition that's making it very hard to function on a daily basis.



· Gram Kracker memory retention fix issue – note that most units have not had this done

· GK Logos

· General Development Notes

· Battery Backup Disabling Circuit

· Cartridge disconnect circuit

· RAM Bank Selection circuit

· GRAM Selection Circuit

· GRAM operation Logic

· Address Registers circuit

· Additional battery backup circuitry

· Mini memory schematic

· Battery Backup circuit

· Main circuit drawing draft (two pages – note one has a little info on the bottom left)

· Bank Switching update circuit

· Battery Drain information

· Battery Drain information sheet (front/back)

· NOT INCLUDED: Receipts (most were stapled)

· Parts list for the GK01

· Battery holder data sheet

· NOT INCLUDED: Article “Application of Static RAMs – Battery Backup” from Electronic Design, March 31, 1983

· NOT INCLUDED: Data sheet, transistors type 2N3903, 2N3904, ETC.

· Five tests for GRAM read/write (writing one byte to GRAM, and see which data was latched – both QI console and regular console)

· Component placement dated 10/02/85 of top PCB

· Component placement dated 10/2/85 for bottom PCB

· NOT INCLUDED: HM6264LP datasheet, HM27C64 datasheet, HM27256 datasheet, HM27C256 datasheet, Hitachi Representatives and Distributors datasheet

· Block diagram


Still to come:

  • Scans of draft of user manual
  • Scan of DC's printouts of the source code (both internal GPL code for the GK loader as well as all the subprograms)
  • Scan of the production checkout code (used to test the units as they were assembled)
  • Schematic diagrams! (woot!)
  • First run historical drafts of the mylars

As per above, all of these archives will be assembled into one archive when I am done and placed on WHTech.

GK Development Notes v1.00.zip

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One more for the day.


1) Gram Kracker binder copy of GPL loader program:

- Page 1-10 – GK Load
- Page 11-23 – Subroutine Data
- Page 24 – Aschex/Quit routine
- Page 25 – BASIC BIAS routine
- Page 26 – Color subroutine
- Page 27-30 – DBASE Routine
- Page 31-32 – DSRLNK Routine
- Page 33-37 – Field Editor (Stack Driven)
- Page 38-45 – Memory Editor
- Page 46-69 – Memory Dump
2)Gram Kracker module modifications – preliminary user manual

3)Gram Kracker Test program (GPL) – possibly a partial printout according to Doug Warren

This leaves:

  • Schematic diagrams! (woot!)
  • First run historical drafts of the mylars
  • Another potential surprise coming up soon (hopefully)


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  • 3 weeks later...



Coming soon. Working on restoring and stitching/making readable. If some of my crowd sourced requests don’t pan out and you want a 45MB file of images to stitch, straighten out, etc, to help me out, PM me.





Great Job, can you post the full schematic picture (or a link)?





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Great Job, can you post the full schematic picture (or a link)?







I have two people working on the schematic at present, and both are doing it in their spare time.


* Ksarul is going to be authoring a modern version

* Sinphaltimus is trying to rebuild the above schematic by overlaying it with new text/graphics


Please be patient. :)

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Next batch is up...this is a hard drive image (usable with TI Image Tool, TI99Dir, and MAME).


Note, this is not a complete dump of the hard drive, but has a lot of great nuggets in it. Corcomp DSR source, MG Explorer source, DiskAssembler source, Triton Turbo XT source, etc. Please note I'm looking for someone to really dig into this to help enhance the README before I put it on WHTech. As soon as Fred and Michael get the Myarc backup format for DC's drive fixed so we can extract, we will have a lot of the remainder of the files that are not in this archive.
Please read the README in the archive for more information and enjoy.
  • BXP Directory – Backup of the MG Explorer Source and object code
  • CCP – Corcomp Disk Controller DSR Source Code
  • DSK1 – Misc utilities Doug utilized
  • DSKASM – This is the final version of DiskAssembler source and object code
  • EXP – MG Explorer – another source code directory
  • FMT – Copyright protection source code for formatting disks?
  • GAME – Task Force by Douglas Warren – 12/25/82
  • GKED – Gram Kracker Editor source code
  • GKLS – Gram Kracker source code
  • GKTST – Gram Kracker production testing/burnin source/object code
  • LDRS – Possibly MG Explorer copyright protection loader code?
  • MDM5 – Ignore. Myarc Disk Manager 5 if using disk image with MAME.
  • PCTI – Triton Turbo XT sidecar source code
  • PCTST – Triton Turbo XT sidecar test code?
  • PEXP – Subroutines to protect MG Explorer?
  • PROD – Appears to be the executables to create production copy protected MG Explorer disks
  • RT – Appears to be many different type of GK Module dumps
  • TI232CC – TI RS232 DSR source code
  • TISYSTST – TI diagnostic tests for different peripherals
  • XBK – Assembly routines/libraries, possibly from MG Smart Programmer?

Warren_Source_Code_Part A_1.00.zip

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The last bit for right now: The GK Draft mylars. These are not production; do not use them. Several of them are partial pages that you will have to reassemble if you choose to print them.



  1. Heiner Cartridge Board information/schematics
  2. Original set of GK disks sent to me/readme
  3. Production Mylars
  4. GK Development Notes
  5. Development/Binder notes
  6. Source Code - what we have recovered so far/Hard Drive Image usable with TIMT
  7. First run Mylars (drafts)
  8. Release


  1. Schematic (master) - large is in bad shape, cannot bring through a blueprint scanner. Ksarul is going to recreate and Sinphaltimus is trying an overlay on the original
  2. Schematics (drafts) - might try to get these scanned, as most are in good shape. Local computer club member has access to one in Norcross, not too far from me.
  3. Remaining hard drive contents - Most are trapped in a Myarc Disk Manager for the Personality card backup format.

I will work with Don and Greg to try to get these all posted on WHTech.





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I have not had the pleasure of going through all these files you've posted yet (though I plan to do so soon). Is there, by any chance, a copy of the MSAVE and MSAVE6 source code included in any of these documents?

No, none of the utility program source code has been added. I don’t think DC had it, looking at his hard drive image. Only possible place he might have it on is floppy. I will ask.

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For all you Krack Heads - I mean Gram Kracker Heads. :)

OK, I feel I've made enough progress to show what I've been doing. Not so much a preservation effort as it is a recreation effort. I'm no engineer but I'm glad to help. I hope to have this completed within a week or two tops. It will at the very least end up ultra Hi-Res (not super low res for this preview) but my intent is to keep it vector for file size and zooming - as long as I can combine the two different programs I'm using to complete this. Sure it needs some clean up (slightly crooked lines and some components not lined up 100% accurately) but I think it's coming along nicely. Hope ya'll think so as well. Still have all those text labels to add. Whew. :)

I've done my best to preserve the integrity of the layout and work done on the original.


Edited by Sinphaltimus
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Thank you Sinphaltimus for taking on the restoration! The original was crusty old and water damaged.

I don't have many ways to "give back" to such an awesome community. When I find a way, I make it happen because, "thank you" to everyone here for making this hobby one of the best. I don't own a GramKracker, I wouldn't know what to do with one if I did, but this, this I can do. :)

You're welcome. I'm feeling confident I'll be completed by this coming Sunday sometime. At that time I will submit it privately to several with access to the original and full blown knowledge to check over my work and ensure accuracy. I find some mistakes along the way and correct as i go so another set of eyes or two or three can't hurt. Once approved, I'll release everything including the dia files. I started with photoshop but will be transferring the photoshop work over to dia before completion as dia will be the final output retaining the super hi res and printability since it is vector based.

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