Toshiba T5200 mods and upgrades

Discussion about old PC hardware.

Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-06 @ 22:53

Hi Ian ..
Would you mind checking my wiring and connections before I attempt reassembly ?
Have I left anything out ? etc.
cheers buddy
VS
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Last edited by Vipersan on 2018-4-06 @ 23:01, edited 1 time in total.
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-06 @ 22:54

more..
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Re: Toshiba T5200 mods and upgrades

Postby REFCODES.ORG » 2018-4-07 @ 15:40

jaZz_KCS wrote:@REFCODES.ORG
Although I don't personally like to see a Gotek FDE inside one of these series (:P), I am still happy to see as many of these machines still in use/working condition/restored as possible. :)


I aggree, it was a hard descision, though after the old 3.5 drive was broke I tried out to refurbish it without any mechanical parts (fearing that the floppy and HDD will break again some day), though unfortunately suffering now from being an accurate vintage artifact :-( I was really lucky to find this thread, all of your discussions were of great help! :-)
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Re: Toshiba T5200 mods and upgrades

Postby jaZz_KCS » 2018-4-07 @ 16:38

Indeed, and you always have the option to rip the emulator out and substitute it with a generic floppy drive, now that you found the safe haven of Toshiba T Series information :) The amount of modifications IanB and Vipersan are undergoing is staggering. I am just happy to have a unit with everything working. So much so that I even storaged teh original working floppy drive and am using a generic Sony one instead. The original drive in working condition is becoming a rare sight these days, so I want to be extra careful.
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Re: Toshiba T5200 mods and upgrades

Postby IanB » 2018-4-08 @ 14:54

Vipersan wrote:Hi Ian ..
Would you mind checking my wiring and connections before I attempt reassembly ?
Have I left anything out ? etc.

Looks OK as far as I can tell. After partial re-assembly, confirm you can still boot from a floppy as that's the time the flush circuit is needed. Also run cachechk.exe to confirm it's seeing an 8K level 1 and 32K level 2 cache (post a screenshot if possible).

I'll see if I can find the Cyrix software that does a formal test on the cache flush.
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-08 @ 15:17

Thanks Ian ..
Btw ..anythoughts on my earlier postings ..re math co processors ...and more importantly to me ..the odd boot behaviour I see with 16 bit ISA cards ?
rgds
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-09 @ 16:17

Not started the reassembly yet..
A rare thing here but the sun was out today ..and little wind..so took the opportunity to get rid of most of that tacky rubber coating on the lower case ...followed by a respray in black and a coat of clear laquer/varnish.
Dont suppose it will ever look genuine again ..but after I'd cut the case already ..why not.
At least it can be handled now without a sticky deposit gluing my hands to the case.
rgds
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Re: Toshiba T5200 mods and upgrades

Postby Auzner » 2018-4-09 @ 20:22

I'm interested in details about the plasma display signalling and power. Does anyone know how it works or have photos?
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-09 @ 21:33

Well Ian ..
The good news is that I have it reassembled ..and I can boot from floppy .
I'll try further tests tomorrow..
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Re: Toshiba T5200 mods and upgrades

Postby ziggystar12 » 2018-4-10 @ 02:14

One thing I've done to mine that I don't see here. I installed a sound blaster pro (with a volume control wheel) and attached a tiny 5v audio amplifier circuit and speaker. This is installed internally with the card in the 16 bit slot and the speaker in the area above the graphics card. Works great! Quick question, on the video bios rom. My chip says 198A. I didn't see many other options, this is a US unit so any benefit to installing the 32k rom? No upgraded rom beyond this one? From time to time I notice random snow in the display. Could it be the graphics card?
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Re: Toshiba T5200 mods and upgrades

Postby ziggystar12 » 2018-4-10 @ 02:23

Looks like replacing the graphics card eliminated the snow so it must be a bad chip. Also, looking for a ram chip or two. I have none, stock 2mb. Would like 4mb if anyone has some to sell!
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-10 @ 09:16

Morning Ian ..
Cant run cachechk.exe ..
presumably not installed with win95 ..and I didn't preinstall DOS ..
If it is a short program ..perhaps you could upload it so I can run it from floppy ?
rgds
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Re: Toshiba T5200 mods and upgrades

Postby IanB » 2018-4-10 @ 10:48

Vipersan wrote:Btw ..anythoughts on my earlier postings ..re math co processors ...and more importantly to me ..the odd boot behaviour I see with 16 bit ISA cards ?

You can fit any 387 compatible maths co-processor (They were made by many companies including Intel, IIT and Cyrix). The original Intel 387 was slow compared with some of the other versions although they are only really useful if you run something that uses the floating point instructions.
I don't know what the problem is with your plug and play config although as I mentioned, plug and play gets confused if some of the signals are missing. Also there is no support for it in the Toshiba BIOS which might contibute to the problem.
If there are any DOS config programs for your hardware, you could try installing those in Config.sys / Autoexec.bat to force a manual configuration before windows starts and it may pick up that config and use it (that works with my audio card).

Vipersan wrote:Cant run cachechk.exe ..


You can download cachechk from here:
http://minuszerodegrees.net/software/CACHCHK4.zip
Run it at a DOS prompt (not in windows) and post a screenshot.

Also download this Cyrix config program:
http://ohlandl.ipv7.net/8570_Tim_OConnor/CYRIX100.ZIP
Extract cyrix.exe and then run:
CYRIX -q
at the command prompt and post a screen shot (This will display the current config of the chip)
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-10 @ 11:03

Thanks Ian ...
got the keyboard stripped down for clean and service atm..
So I'll get on those checks asap..
rgds
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Re: Toshiba T5200 mods and upgrades

Postby IanB » 2018-4-10 @ 16:52

Auzner wrote:I'm interested in details about the plasma display signalling and power. Does anyone know how it works or have photos?

There is a pinout for the display cable connector on the motherboard in the maintenance manual on page B-3
http://www.minuszerodegrees.net/manuals ... Manual.pdf

Apart from power etc it looks like the display needs a pixel clock, 4 bits of data for 16 levels of luminance and H/V sync.
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Re: Toshiba T5200 mods and upgrades

Postby Hamby » 2018-4-10 @ 17:23

Vipersan wrote:Thanks Ian ...
got the keyboard stripped down for clean and service atm..
So I'll get on those checks asap..
rgds
VS


Would love to hear details on the keyboard cleaning, with pix if possible :)
I got some contact cleaner in anticipation of cleaning my keyboard (if you recall, I have problems with the enter key registering).
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Re: Toshiba T5200 mods and upgrades

Postby Hamby » 2018-4-10 @ 17:27

IanB wrote:
Auzner wrote:I'm interested in details about the plasma display signalling and power. Does anyone know how it works or have photos?

There is a pinout for the display cable connector on the motherboard in the maintenance manual on page B-3
http://www.minuszerodegrees.net/manuals ... Manual.pdf

Apart from power etc it looks like the display needs a pixel clock, 4 bits of data for 16 levels of luminance and H/V sync.


Ian, would it be possible to connect any other vga display adapter to the plasma screen of the T5200?

(have in the back of my mind a notion to get a second, non-functioning T5200 or T3200 with a working plasma display and installing an itx motherboard in it, or possibly an intel based Raspberry Pi competitor SBC).
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-10 @ 18:43

Hi Ian I did manage to run Cachechk from a directory in C: root ..using a bootable floppy in A:
The result is attached..
Sadly ..still having keyboard issues even after service..
Some keys still double bounce ..
Some keys dont respond at all ..
for example ..I cant go backwards from a directory in C:
I guess the slash key is junked.
OR ..the T5200 simply doesn't fully accept the T3200 keyboard..??
rgds
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-10 @ 19:07

Curious ..
the backslash key prints the correct character in win95 notepad ...but no response at all when in DOS ?
now I _AM_ confused..??
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Re: Toshiba T5200 mods and upgrades

Postby Vipersan » 2018-4-10 @ 19:37

So ..not a keyboard issue ?
The same behaviour with the original T5200 KB installed (damaged but partially functional)
a bios issue perhaps ?
This will be difficult to explain ..but I'll try.
OK I boot with a floppy in A:
I then type C:
I arrive at the root of C I can then DIR and see the root ..
I can then CD 5200 ..
The directory 5200 is where I placed Cachechk ..
I can run the exe ..
on completion I wish to return to the root of C ..
I cannot ?
I can delete anything I type after the > prompt but cannot C:
In other words it behaves as though 5200 is the root ??and I cannot go back futher..
I remain in the directory 5200 ?
I can A: and see that directory ..
ie the floppy root
I type C: ..but return to the directory 5200 ....and not the root C:
this is most confusing ???
help!
the only way I can get back to the root of C ...is to power down and reboot into A: ..then forward to C:

If I move forward in nested directories ..
the last directory I enter becomes my go back limit..?
ie ..I can move forwards NOT backwards

This odd restriction is only in DOS ..
I can move freely between directories once in windows using explorer and mouse.
..which is why I wasn't aware of it until today
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