Model 200 RAM: Difference between revisions

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The model 200 supports up to 4 banks of 24k each.
The model 200 comes with 24k built in, and supports up to 2 more banks of 24k in the form of ceramic dip modules that plug into the Option RAM #1 & #2 sockets.


There are several ways to add ram.
=TANDY 26-3866=
The original 24K module was Catalog Number 26-3866.<br>
This is a ceramic DIP carrier with 3 8k sram chips and a 40H138 to decode A13 & A14 into 3 different /CS for the individual SRAM chips.


Steven Adolph designed this module to provide all 4 possible banks at once.
[[File:TANDY_26-3866_top.jpg|200px|link={{filepath:TANDY_26-3866_top.jpg}}]]
[[File:TANDY_26-3866_bottom.jpg|200px|link={{filepath:TANDY_26-3866_bottom.jpg}}]]


[[File:TANDY_26-3866.svg|frameless|link={{filepath:TANDY_26-3866.svg}}]]
=Modern Replacements=
https://github.com/bkw777/TANDY_200_RAM
<gallery>
File:TANDY_200_RAM.jpg
File:TANDY_200_Dual_RAM.jpg
File:TANDY_200_Dual_RAM_tsop_14mm.jpg
</gallery>
<!--  -- all dead links now --
This module, designed by Steven Adolph, adds both possible optional 24K banks, for a total of 3 banks when installed.
UPDATE: The pcb and parts below have been replaced by this updated design:
*[https://oshpark.com/shared_projects/o1iXGzr1 PCB]
*[http://www.digikey.com/short/jmq927 Parts]
This is parts to build a single board, although OSHPark will ship you 3 boards. You only need one board for one Model 200 computer. If you want to build all 3 boards, then triple all the part quantities on the digikey cart.
OLD VERSION:
*[https://oshpark.com/shared_projects/tepuH2VQ PCB]
*[https://oshpark.com/shared_projects/tepuH2VQ PCB]
*[http://www.digikey.com/short/q71vcp Parts]
*[http://www.digikey.com/short/q71vcp Parts]
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[[File:200_ram_sa_11.jpg|200px]]
[[File:200_ram_sa_11.jpg|200px]]
[[File:200_ram_sa_12.jpg|200px]]
[[File:200_ram_sa_12.jpg|200px]]
[[File:200_ram_sa_13.jpg|200px]]


[https://photos.app.goo.gl/g1G4bo6FbjJSgcqU2 More Pics]


[https://photos.app.goo.gl/g1G4bo6FbjJSgcqU2 More Pics]
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=More info=
 
https://archive.org/details/Model_200_Portable_Computer_Service_Manual_19xx_Tandy/page/n75/mode/2up
 
http://bitchin100.com/wiki/index.php?title=Tandy_200_RAM
 
http://club100.org/memfiles/index.php?&direction=0&order=&directory=Steve%20Adolph/T200%20Ram%20module
 
http://club100.org/memfiles/index.php?action=downloadfile&filename=m200ram.txt&directory=Steve%20Adolph/mods_to_upgrade_ram

Latest revision as of 19:38, 18 September 2022

The model 200 comes with 24k built in, and supports up to 2 more banks of 24k in the form of ceramic dip modules that plug into the Option RAM #1 & #2 sockets.

TANDY 26-3866

The original 24K module was Catalog Number 26-3866.
This is a ceramic DIP carrier with 3 8k sram chips and a 40H138 to decode A13 & A14 into 3 different /CS for the individual SRAM chips.

Modern Replacements

https://github.com/bkw777/TANDY_200_RAM


More info

https://archive.org/details/Model_200_Portable_Computer_Service_Manual_19xx_Tandy/page/n75/mode/2up

http://bitchin100.com/wiki/index.php?title=Tandy_200_RAM

http://club100.org/memfiles/index.php?&direction=0&order=&directory=Steve%20Adolph/T200%20Ram%20module

http://club100.org/memfiles/index.php?action=downloadfile&filename=m200ram.txt&directory=Steve%20Adolph/mods_to_upgrade_ram