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BIOS for Toshiba T2100

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria
Hi there,

I managed to burn my bios chip on my Toshiba T2100.

I would really appreciate if anyone can make a dump of it's BIOS and send it to me.

My BIOS version is 004B, but I am happy to try any other version of the T2100.

My T2100 model is PA7031E

Thanks,
Branko
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
Hi Branko

I have an 8086 T2100 & could probably dump the BIOS, but I'm away from home for 2 weeks so it would have to happen after that. Perhaps someone else can do it sooner for you? The T2100 are super-rare (well, online at least). What status is yours in? Do you have the Technical Manual (Repair) for it by any chance?

Mine is an early unit with 2 x floppy drives. Their operation is a bit intermittent & 1 column of gas-plasma pixels is out, but otherwise works fine.

Philip
 

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria
Hi Philip,

Thanks for info. I would really appreciate if you can do it for me. If anyone else can do it in mean time it is also good :)

My version is also with two floppy drives. So far screen is ok, no dead spots. Hinge plastics were broken but I will fix them. It worked fine...I opened it for cleaning...and accidentally put chip back in opposite direction and I burned it :(

For now, I only have image of original DOS (in German) and image of Toshiba Test/setup tools. I don't have manual, and it is impossible to find online :)

I ordered new chip from e-bay and if I find BIOS hopefully I can bring it back to life :)
Branko
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
OK, I'll also need to get a 3.5" drive connected up to my XP box, it currently only has 5.25" capability. You see 8086 & MSDOS are at the "modern" end of my collection, my specialty is 8-bit TRS-80. I haven't had the T2100 long & have barely used it, but as I'll need 3.5" disk capability to move programs from the internet to the T2100, then that job needs to be done anyway.

Also, how do I dump the BIOS? Have you got a program that will do this? Perhaps you could send it to me?

Philip
 

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
Hi Branko. I'm home now so can dump BIOS contents. Have you devised a software method yet?

Philip
 

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria
Hi Pavery,

I managed to get BIOS dump, and burned it into chip. It is newer version then my was, but it did work :) This one is version 004C and it is probably dumped by some ROM reader.

Anyway, I played little bit with DEBUG after that. Both commands are here:

C:\> DEBUG
-N MYF000.BIN (resulting file will be named MYF000.BIN)
-R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K)
BX 0000
:0000
-R CX
CX 0000
:8000
-M F000:0 8000 0100 (copy 32K bytes from F000:0 to offset 0100 in local segment)
-W 0100 (write from offset 0100 in local segment)
Writing 8000 bytes
-Q


C:\> DEBUG
-N MYF800.BIN (resulting file will be named MYF000.BIN)
-R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K)
BX 0000
:0000
-R CX
CX 0000
:8000
-M F800:0 FFFF 0100 (copy 32K bytes from F800:0 to offset 0100 in local segment)
-W 0100 (write from offset 0100 in local segment)
Writing 8000 bytes
-Q

My T2100 has only one BIOS ROM. And content of BIOS rom is identical with export of second command (F800 - FFFF).

I guess that first command is for other rom chip which I don't have. Also not sure what it would be...maybe some testing tools, etc.

If you have time, you can try execute both commands and see how it looks like. Would be also good if you can open your computer and see which BIOS version do you have. It is on the sticker on top of BIOS chip.

Cheers,
Branko
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
Great that you got yourself a BIOS. I'll try this weekend to open up my T2100 & see what BIOS version I have.

Philip
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
OK, I've opened up my T2100 but... the display cabling is all shrink-wrapped shut. I don't really want to open all that up as there's a lot of it. Is there a way of glimpsing the BIOS chip without fully dismantling the machine? Where is the BIOS on the motherboard?

I did the above Debug & the first variant worked fine & wrote a file to disk. The second declared an error at: -M F800:0 FFFF 0100. Shouldn't FFFF be 8000?

My disk drives are flaky and it takes multiple attempts to get a write, but hopefully I'll get two files written, then I can see about reading them on a later PC & send them to you.

Philip
 

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria
Hi Philip,

In order to open it, you have to disassemble display first. I don't have Maintainence Manual for it, but yoi can download one for T3100 and the procedure is the same.
Anyway, it is a little bit time consuming :)

The BIOS chip is located bellow keyboard middle-left.

If it is complicated for you, just do not open it..BIOS export will be enough...I can compare it with the one I have and see if it is different.

For the BIOS export, second command should be ok, but I will double check. It should be address space between F800 and FFFF, so the last 32K from address space.

When you export file...you should check it if it is only have FF in it, or different values. When I export file using first command it was exported successfully but all file was filled with FF.

Good luck with FDDs :)

Branko
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
The BIOS chip is located bellow keyboard middle-left.
Just the info I was looking for as with the top lifted up but with the display still attached, it was easy to lift the keyboard & reveal the BIOS chip. See photo showing I have ver 4B:

Philip

20211003_174358[1].jpg
 

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria
Hey, that is pretty cool. This was version of BIOS in my original chip. Could you maybe send me "bin" file produced by first and second command?
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
20211009_092914[1].jpg
Hi Branko. You were going to double check that second Debug command. As it's written, I just get an error.
 
Last edited:

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
Thanks modem7. That appears to work. Is there a Debug command, or otherwise, by which I can verify I actually have the BIOS contents please?
 
Last edited:

modem7

Veteran Member
Joined
May 29, 2006
Messages
7,785
Location
Melbourne, Australia
Thanks modem7. That appears to work. Is there a Debug command, or otherwise, by which I can verify I actually have the BIOS contents please?
The photo in your post #12 shows that the motherboard BIOS chip is a Toshiba TC57256. Because I know that that can be replaced by a 27C256, I know that the BIOS chip is 32 KB in size. The motherboard BIOS normally resides at the end of the upper memory area, so for 32 KB, that corresponds to address range F8000 to FFFFF.

If you post your MYF800.BIN, we can look at it, and make an educated opinion.

The only real way to fully verify the content of MYF800.BIN would be to burn it to a 27C256 chip (speed rated at 200 ns [or faster] like your TC57256), then use that chip to replace your TC57256 chip.
 

pavery

Experienced Member
Joined
Dec 29, 2008
Messages
146
Location
New Zealand
Thanks modem7. I'm just skeptical of the .BIN file created as whilst the directory shows it is 32KB in size, it took a whole lot of Retries and Ignores to get it saved down on to floppy. What I'm thinking is... is there a way in Debug to show the first few bytes of the BIOS chip in hex and maybe the last few bytes? The disk drives: while I'm familiar with 5.25" 360KB repairs, I've never worked on 3.5" Is it likely they just need a head clean & rails/mechanism cleaned/freed up?

In any case I shall attempt to get a 3.5" drive fitted to my 98SE PC so I can get this .BIN file to you & Branko.

Many thanks
Philip
 

silence012

Member
Joined
Oct 21, 2020
Messages
32
Location
Austria
pavery
I use simple command "fc.exe /b file1 file2" to compare two binary files but it is useful only if you have second file to compare with. We can try it with the bios dump I have, but it is different version.

As modem7 mentioned, the best would be to burn these in into some chip and try. Send me your bin files on btrenkoski (at) penluchi.com and I will give it a try. I didn't know that there is a cheap replacement 27C256 :) I paid 20EUR for original EPROM :)
 
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