Microwriter MW4

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jonb
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Microwriter MW4

Post by jonb » Fri Dec 15, 2017 2:30 pm

Found this little machine while rummaging about in the loft for some speaker cable. It's an old Microwriter MW4 with a chorded keyboard. I believe it dates back to 1980 and I found it in an electronics junk store in Hove. It came with a full set of documentation, a zip up bag and a TV interface (which lets you see what you are typing on a screen, like a contemporary word processor.

Anyway.. attached to the underside is a post-it note indicating its power requirements - 12v / 200mA with a standard power plug, annoyingly having reverse polarity. The Sinclair Spectrum Plus 48k adapter seems to fit the bill, but it didn't fire up. Bother... so I took it apart and fed 5v direct to the battery terminals from another PSU I had lying around.
IMG_1041.JPG
Well whaddya know?
..and there it is.

Look closely where the -ve lead connects to the back of the power socket. A component is bridged by a link wire. I did this last time I played with it (long time ago) and there is a message on the post it note saying "remove link on PCB". However, the link is making up for the fact that the fuse is blown, at least that is what I think is underneath the link wire and on testing it appears to be open circuit. The silkscreen says "F1 .500 A" underneath, so I consider that a dead giveaway.

There is a tiny amount of corrosion to the PCB from the 37 year old NiCad cells. I'll order some more in due course.

The main thing is I'm not sure if it really is powered by 12v or not. I can't see a voltage regulator on the board although those two transistor-like units might be doing something with the power. They are marked "10KM 8412" - anyone know?

johnkenyon
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Re: Microwriter MW4

Post by johnkenyon » Fri Dec 15, 2017 9:06 pm

jonb wrote: The main thing is I'm not sure if it really is powered by 12v or not. I can't see a voltage regulator on the board although those two transistor-like units might be doing something with the power. They are marked "10KM 8412" - anyone know?
VN10KM MOSFET manufactured week 12 1984?

/John

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jonb
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Re: Microwriter MW4

Post by jonb » Sat Dec 16, 2017 7:28 pm

Interesting. There is another IC on the board with a date code 8407, so perhaps this one is not as old as I had previously assumed. Looks like a very late model.

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topcat96
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My name is Microwriter MW4 ...

Post by topcat96 » Sun Dec 17, 2017 10:58 pm

The following is from http://www.binarydinosaurs.co.uk/Museum ... /index.php
The Microwriter has an interesting history if only because of who invented it - a bloke called Cy Enfield who's better known for directing the 1964 classic 'Zulu' starring Michael Caine amongst others. After moving to England (Mitcham, Surrey no less) he came up with the idea of a one-handed keyboard and this was the result. Letters were entered using a mnemonic scheme similar to the chord-key set that Doug Engelbart and team came up with when they co-invented the mouse back in 1964-ish. It was claimed it only took a month to learn all the key sequences needed, and it could be twice as fast as writing!
Interesting potted history there.
Image

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jonb
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Re: Microwriter MW4

Post by jonb » Mon Dec 18, 2017 8:09 am

Yes. I did try to learn Microwriting when I first got it way back in the early '90s but I didn't persevere. Might have another go; it's an arcane skill that could be useful, if I ever get one that can be plugged into a real computer. The MW4 was difficult to use thanks to its tiny screen, although the video box makes it friendlier (slow though). You still need to understand the command set, though..

What I would really like is one of those BBC connectable versions, "Quinkey" was it called? I believe it plugged into the user port and acted like a second keyboard using the Microwriter key scheme. It was probably just the case plus keys connected directly to the UP with a ROM to interpret the switch settings.

I often wondered if the MW4 could connect to a machine and be used directly like a terminal. Might make an interesting project.

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Richard Russell
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Re: Microwriter MW4

Post by Richard Russell » Tue Dec 19, 2017 9:23 am

jonb wrote:What I would really like is one of those BBC connectable versions, "Quinkey" was it called?
I've still got mine somewhere; I was never proficient with it but could remember the patterns for the letters. I think I did interface it with a PC in the dim distant past, just for amusement.

Richard.

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jonb
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Re: Microwriter MW4

Post by jonb » Wed Dec 20, 2017 2:38 pm

Well let me know if you want to dispose of it.. :)

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