The price disappeared after I bought the MC600 from the Pulsterā¦ I seemed to me that it was the last one availableā¦
I still enjoying using it. But it is the DOS model (without the GUI).
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davidb
For that reason Iād love to see an MC400 emulator 
The user interface is clean and simple and I would love to see it preserved for posterity in some sort of emulation environment.
Iāve imaged the ROM of one of my dead machinesā¦ 
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Edit: Ah, I see youāve already started! I didnāt see initially that the post below is yoursā¦
I found an interesting recent post about an adventure which may yet bear fruit:
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Yeah, thatās me - Iāve started but my skills run out at:
I have the ROM image, I have the HDK/SDK from Alex Brownās Psion Documentation Project (via his Hackaday page āThe Last Psionā) and thatās about it :-d
And by the way, these machine do not use the 8088 as the title suggests. In common with the Series 3/3a, HC & Workabout ranges they utilise the 80C86.
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Looks like an emulator might be starting to come together - watch the action over on stardot with Pernod and @zedstarr finding their wayā¦
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Looked promising:
but brick wall now hit with lack of documentation for the custom ASICs 
Iām contemplating whether itās worth trying twitter/LinkedIn/Facebook groups to see if any ex-Psion/Symbian engineers can help. But itās ~30 years ago this stuff was current
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This is great!
I think it might worth to tryā¦
Perhaps slightly OT, but as Iād somehow missed that the MC line was a precursor to the whole palmtop adventure, as penance I offer this history:
3-Lib History of Psion
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I remember picking up a glossy promotional brochure for the MC line - it was A4 sized and when you opened it up it looked just like the MC400, full-page pictures of the screen on the left page/keyboard on the right. This must have been 1989/1990 ish. I was instantly hooked 
At that time having a truly portable computer this size blew me away! Iād used āluggableā PCs at work (something like this luggable Compaq 386 ) and knew smaller was better 
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Finally got round to re-purposing the keyboard from the dead MC400 as a USB keyboard - thanks to Frank Adamsā Teensy LC sketch I worked out the matrix and managed to hack it around into actually working as a USB keyboard [Apologies for the slow one-handed typing - not easy when holding the phone in the other hand ]
My Teensy LC code is here
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A little more progress:
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My MC400 collection is now up to 4! ā¦but all 4 have LCD faults:
2 of them have serious āscreen rotā (or LCD ācancerā or ābleedā depending on who you ask!) - looks like mechanical failure of the frontmost layer (polariser?)
1 has a screen that is completely off/dead - I havenāt looked but surely thatās just a cable/connector fault.
1 has a 2 or 3 pixel wide line of dead pixels halfway up the screen - I think is again a connection issue between the PCB and the glass substrate (I remember these little jelly pads with carbon conductors in the when taking apart LCD screens in my youth )
1 of the machineās keyboards had been battered, it looks concave in the middle and another machine has a really quiet speaker.
Surely I can piece together 1 good machine from the 4ā¦ but I need t set aside a couple of days maybe to do it properly.
For central creeping blackness, one suggested solution is warmth - face down in sunlight, on a radiator, or in an oven on a very low heat - see the final two minutes of this video:
the success recipe seems to be 90min @ 85C, where small temperature changes made a huge difference
(via)
Dead rows or columns are of course something else - perhaps a failed flexible connector?
And any creeping blackness from the edges of an LCD could be a leak or a seal failure.
Thanks, Iāll try that.
Someone also sent me a link to this - https://www.youtube.com/watch?v=RyspNW3G-yE
Which is basically rubbing with a cotton bud, I wonder if the friction causes enough localised heat to do a similar thing? I tried rubbing my screen with a cotton bud but it only seems to have redistributed the splodges, not got rid of them.
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after a 90 min session at 85C, then a 90 min session at 95C:
All that seems to have happened so far is the blotches have coalesced
I baked the whole assembly - there are 8 x 3.3uF 50V electrolytics on the PCB - if the baking fixes the screen theyāll definitely need replacing.
Hmm. I wouldnāt go any hotter, but it might be worth one or two more cycles? Comparing photos will tell you whether itās making progress in the right direction.
Is it a bit smaller? It looks like it might beā¦
Iād say so, as well. But not as much that it would be really encouragingā¦
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Last week I was on a work trip in Central London and couldnāt resist visiting Psionās old London HQā¦
Some updates on the emulation effort:
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