The T5200 has 2MB of memory soldered on board and an expansion SIMM board with 6 and a half SIMM slots but uses proprietary 40 pin SIMMs.
Here are details on a mod to add 8MB of RAM using a standard 72 pin 8MB Parity SIMM. (Requires at least 2MB of proprietary SIMMs already fitted)
Use this info at your own risk, don't blame me if you damage your T5200!

The above shows both empty and fully populated boards with the proprietary SIMMs
The SIMM slots are numbered from left to right IS17 (A & B), IS16 (A & B), IS15 (A & B) and IS14 (parity)
SIMMs must be fitted in pairs as they are only 16 bits wide and the processor is 32 bits wide. Each pair of SIMMs gives a 2MB expansion so the memory can be expanded by 2, 4 & 6MB (2 + 2 + 2) however the centre pair of SIMMs can take a larger SIMM pair of 8MB giving a total of 14MB memory (2 + 8 + 2 of SIMMs plus 2MB on board). The RAM chips on the 8MB SIMMs are larger than those on the 2MB SIMMs and there was insufficient room for the Parity chips so they are fitted separately on the 30pin SIMM (IS14). Note although this is a 30pin SIMM it is a proprietary pinout.

The memory size is detected in order left to right, so you must have a 2MB pair of SIMMs fitted before you can fit the 8MB pair + parity.
This means you must already have 2MB of standard SIMMs fitted in order to do the 8MB mod described below.
If you don't have any additional memory you can still mod your system but it will be more complicated and will be discussed in another post.

First you need to obtain a standard 72 pin 8MB Parity Fast Page Mode (FPM) SIMM and some 40 way ribbon cable (e.g. an old IDE cable)
Then use hot melt glue to stick this SIMM to the edge of the parity socket (IS14) making sure no electrical contact is made:

Note the above board already has the required 2MB of standard SIMMs fitted as mentioned above. (You could optionally fit another 2MB in IS15 as well to give the maximum 14MB after this mod.)

Before proceeding any further, make sure there is enough clearance to fit the board back in the T5200. (You will almost certainly need to dismantle the T5200 completely to fit it back in)

Rip the ribbon cable back to 36 ways and cut into two strips approx 15cm (6in) long. Then using a ruler and sharp knife, score a line about 2mm from the end of one of the ribbon cables and do the same on the other side (not the other end) then pull the 2mm strip of insulation off using a pair of blunt nosed pliers. This should leave 36 wires exposed on the end of the ribbon.
Solder the exposed wires to pins 1-36 of the SIMM and then repeat this for the other ribbon, soldering to pins 37-72.

Then turn the board over and solder the ribbon wires to the centre connector (IS16) according to the following table:
(I suggest wiring all the data lines first as they are all straight with no wires crossing)

Wire 1 to Pin 8 (Ground)
Wire 2 to Pin 2B (Data 0)
Wire 3 to Pin 2A (Data 16)
Wire 4 to Pin 3B (Data 1)
Wire 5 to Pin 3A (Data 17)
Wire 6 to Pin 4B (Data 2)
Wire 7 to Pin 4A (Data 18)
Wire 8 to Pin 5B (Data 3)
Wire 9 to Pin 5A (Data 19)
Wire 10 to Pin 1 (+5 VDC)
Wire 11 Not connected
Wire 12 to Pin 6 (Address 0)
Wire 13 to Pin 7 (Address 1)
Wire 14 to Pin 13 (Address 2)
Wire 15 to Pin 14 (Address 3)
Wire 16 to Pin 24 (Address 4)
Wire 17 to Pin 25 (Address 5)
Wire 18 to Pin 31 (Address 6)
Wire 19 Not connected
Wire 20 to Pin 9B (Data 4)
Wire 21 to Pin 9A (Data 20)
Wire 22 to Pin 10B (Data 5)
Wire 23 to Pin 10A (Data 21)
Wire 24 to Pin 11B (Data 6)
Wire 25 to Pin 11A (Data 22)
Wire 26 to Pin 12B (Data 7)
Wire 27 to Pin 12A (Data 23)
Wire 28 to Pin 32 (Address 7)
Wire 29 Not connected
Wire 30 to Pin 1 (+5 VDC)
Wire 31 to Pin 33 (Address 8 )
Wire 32 to Pin 34 (Address 9)
Wire 33 to Pin 20B (Row Address Strobe 3)
Wire 34 to Pin 17B (Row Address Strobe 2)
Wire 35 to Pin 22A (Parity bit 3 - bits 16-23)
Wire 36 to Pin 22B (Parity bit 1 - bits 0-7)

Wire 37 to Pin 18B (Parity bit 2 - bits 8-15)
Wire 38 to Pin 18A (Parity bit 4 - bits 24-31)
Wire 39 to Pin 23 (Ground)
Wire 40 to Pin 16B (Column Address Strobe 0)
Wire 41 to Pin 16A (Column Address Strobe 2)
Wire 42 to Pin 21A (Column Address Strobe 3)
Wire 43 to Pin 21B (Column Address Strobe 1)
Wire 44 to Pin 17A (Row Address Strobe 0)
Wire 45 to Pin 20A (Row Address Strobe 1)
Wire 46 Not connected
Wire 47 to Pin 19 (Read/Write)
Wire 48 Not connected
Wire 49 to Pin 26B (Data 8 )
Wire 50 to Pin 26A (Data 24)
Wire 51 to Pin 27B (Data 9)
Wire 52 to Pin 27A (Data 25)
Wire 53 to Pin 28B (Data 10)
Wire 54 to Pin 28A (Data 26)
Wire 55 to Pin 29B (Data 11)
Wire 56 to Pin 29A (Data 27)
Wire 57 to Pin 36B (Data 12)
Wire 58 to Pin 36A (Data 28)
Wire 59 to Pin 40 (+5 VDC)
Wire 60 to Pin 37A (Data 29)
Wire 61 to Pin 37B (Data 13)
Wire 62 to Pin 38A (Data 30)
Wire 63 to Pin 38B (Data 14)
Wire 64 to Pin 39A (Data 31)
Wire 65 to Pin 39B (Data 15)
Wire 66 Not connected
Wire 67 Not connected
Wire 68 Not connected
Wire 69 Not connected
Wire 70 Not connected
Wire 71 Not connected
Wire 72 to Pin 35 (Ground)

Note if a pin has "A" on the end it has to be soldered to the "A" side of IS16 and "B" means soldered to the "B" side of IS16
If no "A" or "B" is mentioned then either side can be used as they have the same signals, however note that the "A" and "B" sides have independent drivers so they are not connected together electrically. (The "A" side is the one closest to PJ1 - see second photo below)

Note that wires 1 & 72 in this picture are connected to alternate ground points, not the pins detailed above.

Another view showing "A" and "B" rows :

After finishing, double check your wiring and if you have a multimeter, do the following tests:
First make sure +5v and ground aren't shorted together, then check continuity between +5v on the pcb (e.g. the + side of the electrolytic capacitor) and the wires going to the 8MB SIMM listed above as +5v. Do the same for the ground lines.
Finally connect the board up, power up and hopefully your BIOS will detect the extra RAM.

Hi,

nice job integrating the XTIDE BIOS,
i have a Sanyo Notebook with very similar BIOS, which seems to have lot of freespace on its 27C1024 ROM.
But i have no clue where to insert the XTIDE Stuff.

How did you managed this ?

The Device is a Sanyo 18NB Computer. (added BIOS File)

You can use 29C1024 for 27C1024. its Flash ROM.

matze79 wrote:

i have a Sanyo Notebook with very similar BIOS, which seems to have lot of freespace on its 27C1024 ROM.
But i have no clue where to insert the XTIDE Stuff.
How did you managed this ?

You put the XTIDE image in the free space and then make a small patch to the BIOS extension ROM scanning code so that it initialises XTIDE in it's new location.

Try this:

I put a standard build of the 386 version of XTIDE in the ROM image.
Note this won't work with Windows 2/386 or Windows 3.0 due to workspace conflicts. It should work OK with Windows 3.1 or later.
I made a patched version of XTIDE for the T5200 which used some different workspace so I could run all versions of Windows in a multiboot setup but those changes may conflict with your BIOS so I used the standard version for now.
It might not work with an existing small drive unless that drive is repartioned and reformatted so test with a new larger drive if there is a problem.

Use at your own risk, it's completely untested.

If it works, you can replace the XTIDE part with any new or alternate build by overwriting the data at 0x15000 in the file and then updating the checksum byte at the end of the file.

Thanks unfortunaly i'm not fit in x86 asm, patching a bios is beyond my abilities.

i will try it when i get a "Empty ROM" 😀

i don't run Windows, the Machine only has 1mb RAM and even Windows 3.0 is no Fun with less then 2megs 😀
It seems Toshiba and Sanyo has also Similar Floppy Drive, i have a 26 Pin Drive inside too.
Seems your Floppy Cable mod should work here too 😀

Hey, IanB, could you share what was involved in your processor upgrade? I know Cyrix/TI 386/486 upgrade CPUs are rare, but in case I can get one, I'd like to know... I see the 40mhz ones on ebay once in awhile... never see 20mhz, so I assume that's the hardware mods you had to make...

Also, what is the cause of the 528mb HD partition limit? I once partitioned a 6gb HD under DOS 6.22 into 3, 2gb partitions on my DOS desktop. if you replace the T5200's 100mb drive with a 4gb CF card, with the modified BIOS, would you still have to have a 528mb partition? Or could you have two, 2 gb partitions using drive overlay software?

Hamby wrote:

Hey, IanB, could you share what was involved in your processor upgrade? I know Cyrix/TI 386/486 upgrade CPUs are rare, but in case I can get one, I'd like to know... I see the 40mhz ones on ebay once in awhile... never see 20mhz, so I assume that's the hardware mods you had to make...

No, you can fit a 33Mhz or 40Mhz upgrade CPU in the T5200, it will just run at 20Mhz unless it has built in clock doubling. The hardware mods improve the performance of some of the upgrade CPUs but aren't essential and the CPUs will work if you plug them in without any mods albeit with reduced performance.
I'll go into more detail when I do a post describing the hardware mods

Hamby wrote:

Also, what is the cause of the 528mb HD partition limit? I once partitioned a 6gb HD under DOS 6.22 into 3, 2gb partitions on my DOS desktop. if you replace the T5200's 100mb drive with a 4gb CF card, with the modified BIOS, would you still have to have a 528mb partition? Or could you have two, 2 gb partitions using drive overlay software?

The 528MB limit was caused by a screwup in the design of the BIOS int13 interface which resticted the range of cylinders, heads & sectors and affected all systems of that era. An updated translating BIOS like XTIDE or a drive overlay program allows operating systems to access the rest of the drive.
DOS itself can access 8GB maximum although the FAT16 format is limited to 2GB so you can create a 2GB primary partition and a 6GB extended partition with three 2GB logical partitions in it giving four 2GB partitions max on an 8GB CF card. You don't need drive overlay software as XTIDE performs the same function.

Hi Ian ..
The simm arrived saturday ...and so I decided to make a start on the memory mod ..
It is double sided and quite thick so figured probably best to fit it flat ..
There is just enough room inside the last 40 pin simm slot to superglue 2x nylon M1 bolts though these have to be eased apart slightly to mate with the holes in the simm stick ..
It looks as though it might provide a good mount and thus I can mount the memory flat- ish
See pics ..
Let me know if you foresee any problems before I make this permanent ..
rgds
VS

Vipersan wrote:

Let me know if you foresee any problems before I make this permanent ..

Don't see any significant issue with that mounting, although the cable length will be slightly longer. The only issue I can see is that the superglued nylon bolts will easily break off the PCB surface if stressed, perhaps hot melt glue or a combination of both would be better.
I only mounted mine the way I did because I already had the extra 2MB of proprietary SIMMs to go from 12MB to 14MB so I have them plugged into IS15:

That type of mounting could be the answer for someone who doesn't have the first 2MB of proprietary SIMMs as they could mount a second SIMM in a similar way and daisy chain all the wires from the first simm except the RAS lines.

BTW if you want to shorten the ribbon cable you could connect all the lines to the same pin numbers on the IS15 pair instead of the IS16 pair as they all have the same signals except the four RAS lines which have to go to the pins on IS16. (I know using the signals from other slots is OK because thats how my triple SIMM mod works).
It's also probably a good idea to take some photos while you are wiring in the ribbon cable so that layers of wiring can be checked if you have a problem. It's easy to make an "off by one " error when doing this mod.

Also, before wrapping the cable around you might want to fit a couple of 100uF low ESR electrolytic caps across C22 and C15 (negative sides pointing to each other) which I found fixed an occasional freezing issue with Windows NT (didn't affect DOS or Windows 95). This problem only happened when one of the high performance upgrade processors was fitted and even affected the machine with only original proprietary SIMMs so wasn't being caused by the RAM mod itself. Win NT stresses the PSU and introduces ripple on the +5v line by using the HLT instruction to stop the processor when idle and this was causing instability that this cap mod seems to have fixed.
You have to wrap the caps around the board leaving enough room for the ribbon cable and might need to cover the long exposed wires with sleeving to avoid shorts.

I will indeed add re-enforcement with hot melt glue ...
It can only help ..
Also ...I'm going to use multicoloured ribbon that follows the resistor colour code ..which may help me make less errors ..
my eyes are not good.
rgds
VS

Ian, have I told you that you're the man?

You're the man!!!

Had a friend visit today with his EPROM programmer and UV eraser. The patched '90 award BIOS worked flawlessly at once! I can finally run every type of HDD and boot from every floppy I want 😎

Many, many thanks!

Hi,
This is the topic i was looking for!
I have two T5200/100 which are fine except on both machines the floppy does not work.
At first i have no intention to upgrade other things like RAM, CPU or different harddisk, just want to be able to get software onto the toshiba.
So i guess to make an adapter cable like Ian described should make it possible to get a normal floppy drive working without further modifications ?

My first T5200 was built in Japan in 1988 according to the date codes on the ICs.
There is no actual BIOS, i can only start setup via the test3.exe from the DOS path and it shows no time or date in it and is just plain text, without ascii graphics.
Does not look like any i saw here as a screenshot. Seems to be a very old bios. It runs DOS 4.11.
Second one was built in the US in 1992. It has a more modern BIOS (Award ?) and runs DOS 6.22 with Win 3.1 installed.

Because the case and keyboard of the older one is better and has less screws to open it i swapped the mainboard from newer one and it still works fine but the floppy.

So, first thing would be get a floppy working and then install Win 3.11 and some other software, that would be great.
If i would like to change the BIOS to swap the Conner disk against something else... would it be possible to use any newer patched BIOS or would i need to stick with the version which is installed now ?

Regards,
Olaf

Hi Olaf ..and welcome..
Some amazing work being done here by Ian and others..
Yes you should be able to replace the bios chip with one programmed to allow drives other than the Conor to be used ...
as to the floppy ..
Ian has provided details to make a new IDC lead which allows a standard 1.44 floppy drive to be used in place of the proprietory Toshiba drive ..
All the info you need is in this thread ..so really it is just down to your abilities to implemement the mods..
rgds
VS

@Vipersan:
Yes, Ian pointed me to this thread here within a different forum.
I already tried to make my own adapter cable but it did not work but i was not aware of some of those toshiba specialities 😉
Hopefully i will get the floppy working with the cable layout from this thread.

I have no equipment to burn the bios by myself... have to check if my local electronics store can do that for me...

Thanks so far!

Regards,
Olaf

kultakala wrote:

@Vipersan: Yes, Ian pointed me to this thread here within a different forum. I already tried to make my own adapter cable but it […]
Show full quote

@Vipersan:
Yes, Ian pointed me to this thread here within a different forum.
I already tried to make my own adapter cable but it did not work but i was not aware of some of those toshiba specialities 😉
Hopefully i will get the floppy working with the cable layout from this thread.

I have no equipment to burn the bios by myself... have to check if my local electronics store can do that for me...

Thanks so far!

Regards,
Olaf

Hi again Olaf ..
All I can say is that Ians adapter cable definately works ...
I can confirm this as I'm using one on my 5200 atm ..
rgds
VS

I went the way and ordered a 34->26 pin FDD converter, which should arrive shortly and should work out of the box.

Welcome to the world of old Toshibas 😀

kultakala wrote:

So i guess to make an adapter cable like Ian described should make it possible to get a normal floppy drive working without further modifications ?

Hi kultakala,
Yes, both myself and vipersan have made up the cable and got standard floppy drives working with the T5200.

kultakala wrote:

My first T5200 was built in Japan in 1988 according to the date codes on the ICs. There is no actual BIOS, i can only start setu […]
Show full quote

My first T5200 was built in Japan in 1988 according to the date codes on the ICs.
There is no actual BIOS, i can only start setup via the test3.exe from the DOS path and it shows no time or date in it and is just plain text, without ascii graphics.
Does not look like any i saw here as a screenshot. Seems to be a very old bios. It runs DOS 4.11.
Second one was built in the US in 1992. It has a more modern BIOS (Award ?) and runs DOS 6.22 with Win 3.1 installed.

Sounds like your machines might have earlier and later bios versions to the ones we have so far.
If you get your floppy drive working, perhaps you could dump your BIOS and maybe your VGA BIOS as well to floppy and post them here for me to look at.
To dump the main BIOS, download the following zip file:
http://www.bockelkamp.de/software/discontinued/bios1351.zip
Extract the file BIOS.EXE from the above downloaded zip file and copy it to a bootable floppy.
Also copy DEBUG.EXE from a standard MSDOS install to the floppy

Boot the T5200 using the floppy and at the A:\> command prompt type:

BIOS D A:\BIOS.BIN

which should create a 64K file called BIOS.BIN on the floppy
To dump the VGA BIOS type the following followed by enter after each line at the A:\ prompt:

DEBUG
N VGA.BIN
M C000:0 FFFF 8000:0
R BX
1
R CX
0
W 8000:0

You should end up with a file VGA.BIN on the floppy

I think files from your newest board would be most useful, but you can post both sets if you want.

kultakala wrote:

If i would like to change the BIOS to swap the Conner disk against something else... would it be possible to use any newer patched BIOS or would i need to stick with the version which is installed now ?

I would recommend the 5.30 Award 1990 BIOS as that is the most recent we have so far (file on first page of this thread) but if your one is more recent I will look at patching that one as well.

I hope my cable will work... still have 26 pin ribbon cable and 26 pin headers but need to get 34 pin ones...
If its working i will make the Bios dumps of course.

Btw, this is the setup screen of the newer mainboard:

The chips containing the bios are on the lower left under the keyboard, right ?
These are the ones with the newer bios:

And these are the old ones:

The 5200 with the older bios is not starting after i changed some lines in the config.sys.
After booting it halts with "internal stack error".
I can fix it when the floppy works again... or i can swap the hard disk, then i can start it up.

The bios is in the 1024 Eprom chip AM27C1024
and the Toshiba 1024D
IC30

Paper labels 002A & 006A
rgds
VS
If you can get access to an Eprom programmer these chips are easily read ..

kultakala wrote:

The chips containing the bios are on the lower left under the keyboard, right ?
These are the ones with the newer bios:

Yes, as vipersan says the 002A and 006A ones are the BIOS chips. The other similar chip (012A) is the keyboard controller.
The VGA BIOS is on a separate EPROM on the video board which is accessed via the ISA slots panel on the back of the machine
Based on those labels and the screen grab, this is probably what you have:
002A is Award 1988 V1.20 which was the original ROM in my machine and won't recognise 8MB RAM SIMMs.
006A is Phoenix 1989 V3.00 (This is the same as the original ROM in vipersan's machine).
But I can confirm that if you post the dumps.

We are both now running the Award 1990 V5.30 BIOS so that will likely work for you as well.

IanB wrote:

We are both now running the Award 1990 V5.30 BIOS so that will likely work for you as well.

You aren't running my bios?