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Toshiba T3200 portable PC, 286 from 1987

PostPosted: Thu Mar 05, 2015 2:30 pm
by AlexC
This isn't a laptop. It's a portable 12MHz 286 PC from 1987 with 1MB RAM, 40MB hard drive, 3.5-inch floppy drive, an orange plasma screen and two expansion slots in the base.

Info here: http://www.computinghistory.org.uk/det/4435/Toshiba-T3200/

Photos of someone else's here: https://www.flickr.com/photos/anachrocomputer/8572852576/

I bought this via Trade Me based on the previous seller's description and thinking that the problem might just be a CMOS battery error. But it's not - I've removed the CMOS battery (no leakage). There's something else wrong. I'm not sure what, but I do have a theory.

Sometimes when switching it on the screen will stay blank but all the LEDs will stay on. Other times the screen will work and the machine will complain 'ERROR CMOS CHECKSUM' and go no further. Sometimes it will get past that point and give a keyboard error, sometimes a memory error...

But at other times it will boot through to the BIOS screen, complain about checksums, allow me to 'Press F1 to continue' and then start the boot process. The furthest I've managed to get so far is 'Starting MS-DOS...' (so I guess that's MS-DOS 6.xx?) before it locked up, but that may have been due to the wrong hard drive being defined in the BIOS (i.e. it read the MBR but didn't get much further).

So I think the screen, the hard drive, floppy drive, RAM, keyboard, etc. are actually all fine. What's wrong is at the system level.

I have the PDF for the service manual and it talks about checking the output voltages from the PSU. I don't really feel like dismantling this to find out, but my theory is that the voltage to the motherboard is a bit low, which leads to random logic errors. Depending on when in the boot cycle those errors occur, the boot process fails at a different point. Maybe a damaged capacitor or something? I don't know enough to be sure, so I'd probably do more harm than good if I pulled it apart.

It's a lovely, clean machine complete with original Toshiba carry case and I dearly want it to work because the orange plasma screen is great and the keyboard is a delight. The only missing part is a plastic wheel for the brightness control, but the contrast one is still there and the screen works fine.

The previous seller said the PC was working recently, so this is apparently a new problem. There are no funny smells, no smoke, no burning. I don't think the problem is a terminal one.

I paid $100, i.e. too much, though these go for more than that on eBay in a broken state and considerably more when working. It's probably worth more in parts.

My preference would be to get it working and keep it. My second choice would be to sell it and get at least some of the purchase cost back (and take this as a lesson to test things in person before buying).

Any ideas, thoughts, offers?

Re: Toshiba T3200 portable PC, 286 from 1987

PostPosted: Thu Mar 05, 2015 4:00 pm
by SpidersWeb
Is this the one that got pulled from trademe last week? If it is, I had a $50 autobid on it after the bid cancelling/repricing but then it got canned.

If I had it with me I'd be doing these things (stopping with the list as soon as it was running)
- replacing that CMOS battery
- giving the PSU some "on" time and seeing if anything changes, possibly checking the outputs on a scope
- attempt to boot from 720KB system diskette - DOS 3.2 or 3.3 - (to see if it makes a difference, probably not)
- open system unit and reseat anything that's reseatable
- if no luck with that - then looking for broken solder joins
- if no luck with that - making a sad face and keeping it for parts to help with a future unit

Re: Toshiba T3200 portable PC, 286 from 1987

PostPosted: Thu Mar 05, 2015 4:05 pm
by AlexC
Yes, that's the one. He relisted it with a Buy Now and I did. Buy in haste, repent at leisure...

It is a nice machine, though. Just now it booted twice to a DOS prompt before spontaneously rebooting while I was typing. I took some photos during the boot process with a Post-It note with today's date, so at least I can prove it gets that far - sometimes!

I think your points are all valid, especially about leaving the PSU on for a while.

As for parts, I don't think anything would fit! Everything in this seems to be Toshiba-specific. I don't recognise the interface for the hard drive at all, nor the floppy. So it might be great for spares, but only for another T3200.

Re: Toshiba T3200 portable PC, 286 from 1987

PostPosted: Fri Mar 06, 2015 7:57 am
by SpidersWeb
haha, yeah I meant parts for other 286 era Toshiba's :) there is a few of them around - seem to be popular machines here.
Parts like the 26 pin MFM hard drive, plasma display, 26 pin DD floppy drive etc are quite tricky to come across when you need them.

But since it boots, I think there is a good chance that reseating cables and/or giving it more power time may clear it up.

Re: Toshiba T3200 portable PC, 286 from 1987

PostPosted: Sun Mar 08, 2015 7:08 pm
by AlexC
Progress is being made, though with little input from me...

I've been leaving it switched on for a while to see what happens. Now it boots more often than not, to some kind of menu system. There's Xtree Gold Pro, a few games including Lemmings, and I've managed to get into Windows 3.0 on a few occasions too.

The machine still hangs or reboots after a few minutes, but seems to be getting better with time. And it also seems to work slightly better once it's warmed up, so maybe there's a problem with some component or other that needs a bit of heat to work properly, or expand to make a better electrical contact.

Seems to have a 120MB hard drive instead of a 40MB one, partitioned as 70MB and 50MB-ish. Definitely 1MB RAM.

I've never heard of fixing things by leaving them alone before, but I like the concept!