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Saw some pictures of the TI-99/8 lately and it brings up some questions regarding its keyboard.

 

  • Manufacturer?
  • Do all 99/8 revisions use the exact same keyboard?
  • Typing experience compared to the TI-99/4a
  • Same ribbon cable approach as in the TI-99/4a ?
  • Was the keyboard used in other home computers of that era as well?

 

Perhaps some of the 99/8 owners can share their experience with the 99/8.

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http://www.ti99.eu/?attachment_id=123

http://www.ti99.eu/?attachment_id=87

 

My keyboards works fine.

Jens-Eike has problems with his, some keys don't react at all, some keys auto-repeat too often.

 

I know about many 99/2 having keyboard problems.

Not sure if Hex-Bus and its slave mode offers the possibility to come up with a Hex-Bus Keyboard to overcome the problems with the installed keyboards.

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1 hour ago, kl99 said:

http://www.ti99.eu/?attachment_id=123

http://www.ti99.eu/?attachment_id=87

 

My keyboards works fine.

Jens-Eike has problems with his, some keys don't react at all, some keys auto-repeat too often.

 

I know about many 99/2 having keyboard problems.

Not sure if Hex-Bus and its slave mode offers the possibility to come up with a Hex-Bus Keyboard to overcome the problems with the installed keyboards.

 

Klaus, from the pictures it was not clear if you are referring the 99/2 or 99/8. 

EDIT: It is the 99/8 from looking at some of the previous pictures.


I suppose you have both (quite sure about the 99/8 as I’ve seen your unboxing video). 

 

My question was specifically about the 99/8. But interested in the 99/2 keyboard as well.

 

Edited by retroclouds

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The keyboards were made by Mitsumi (or at least the two I have were). . .and many of them exhibit the same types of problems as the Mitsumi keyboards on the 99/4A, based on comments I've seen over the years. I know the keyboard was replaced on one of mine about 20 years ago using a spare the then-owner (Steve Eggers) received from somewhere, as it was having serious issues at the time.

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The keyboard of my 99/8 is an Alps (labeled 12KF062A). It works fine, the typing is quiet soft and precise. I already saw the Alps switch used in it, in the Toshiba T3200 laptop. The keyboard connector differs from the 99/4A one. It has 20 pins.

 

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I have three (99/8). Two of the keyboards will repeat keys. Haven't taken the time to remove them and clean the keyboards. 

 

I have two hexbus drives that have become unreliable. Any alternatives, I recall a hexbus drive before from, I think, Megatronic. 

 

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2 hours ago, TI 99/8 said:

I have three (99/8). Two of the keyboards will repeat keys. Haven't taken the time to remove them and clean the keyboards. 

 

I have two hexbus drives that have become unreliable. Any alternatives, I recall a hexbus drive before from, I think, Megatronic. 

 

The Mechatronic Hexbus drive is a 2.8 Inch Quick Disk. They are harder to find than the original hexbus drives are (I have two of the Hexbus drives and a Quick Disk). There is also a recent effort to make an SD Hexbus drive that is nearly feature complete. I also have a lot of the TI Hexbus chips which would make it possible to make new drives (Fabrice Montupet recently did this). What other things do you have for the 99/8? I also have two of them, a 128K RAM card, an Armadillo Interface (round cable), a 512K RAM card, and an RS-232 card with a 99/8 DSR. I also have to finish scanning the TI design spec for the 3.5 Inch TI Hexbus drive.

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have to ask this, without starting a copyright/patents war.

Would it be legit to do a replica (board) of the 99/8 and are all components used still available today?

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Wasn't there a wide grant of rights to user groups? I don't know whether this encompassed the hardware as well.

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7 minutes ago, retroclouds said:

have to ask this, without starting a copyright/patents war.

Would it be legit to do a replica (board) of the 99/8 and are all components used still available today?

A plain copy is probably impossible, too many custom chips. The TMS9995 is non-standard with internal RAM disabled.... It would be easier to emulate the internals with a CPLD or alike.

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There are five custom chips on the board that are not commercially available. That said, the complete internal logic for four of those chips (POLLO, OSO, MOFETTA, and VAQUERO) exists in the form of detailed gate schematics. The fifth one (AMIGO) is a bit trickier. We have the equations for the portions of it that do combinatorial logic, we have the complete functional pinout, and we have the detailed description of the portion that manages the overall system memory. That data should allow a replacement to be coded, but it hasn't been attempted by anyone yet. @jens-eike also hit upon another potential issue--the somewhat mutant TMS9995 used by the 99/8. The rest of the board is either standard, commercially-available chips or TI GROMs (which can probably be emulated using ATMEGA1284s programmed as UberGROMs).

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As for the AMIGO and the other chips, we may have a chance to re-engineer some things via my emulation in MAME, which proved to be functional (it works, it can't be too far from the real thing :) ). But that is certainly not enough, the CPU would need to be emulated by a FPGA and so on ...

 

And the 22 GROMs should be emulated by something more handy...

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