Category Archives: Retro Tech

Amstrad NC100


The Amstrad NC100 was released in 1992 by Amstrad as an all rounder for word processing, spreadsheets etc. The kind of run of the mill tasks most professional people wanted.

It is about the size of an A4 page with a good sized keyboard with a nice action. The screen is a small LCD that doesn’t have a backlight and if my unit didn’t have an intermittent fault it would be splendid!

The Wikipedia article is a good source of information here.

Thorn EMI Liberator

c6fcf7c869428cc478bd4e24cd345e56The Thorn EMI Liberator was developed in the UK in the 1980s for use by the British Civil Service. The idea was to give the civil servants a portable text processor that they could carry around with them for taking notes. It’s an unsung machine and has dropped off the radar for many. In fact it never made it onto the radar for most of us.

The Register have done a series of well written and researched articles that you can read here, here and here and so I won’t go over the old ground. I couldn’t hope to do as nice a job as Tony Smith.

My Liberator looks a little weary. It has no badges, the handle/stand is missing and the battery pack was decidedly fluffy. However it’s nearly thirty years old an I forgive it.

It’s an interesting little machine. About the size of an A4 piece of paper and around an inch thick it’s slightly bigger than a Sinclair Z88 or an Amstrad NC100.

I read that it runs CP/M-80 though I think the text editor is all encompassing and so you can’t see the OS. I say “I think” because mine just beeps but there is no screen output. The keyboard has a nice feel and the keys are a good size. This should make typing easy. Time will tell.

One thing worth noting is that instead of the standard RS-232 ports common at that time, the Liberator comes with a pair of S5/8 ports. These were intended to be a simpler version of RS-232 but they didn’t catch on. Nice try though.

6fd0a457b2a93975c2b956869ecab35bCuriously my machine came with an Epson PF-10 serial floppy disk drive. There is a Dymo label on the back of the Liberator identifying which port to connect it to and a cable to convert from the large S5/8 port to the smaller socket on the back of the PF-10.

Files and Documents

Here you can find the technical reference manual scanned and converted into PDF format.

For practical reasons it’s in several parts.

 Telefunken Reference Manual (German) Part1

 Telefunken Reference Manual (German) Part2

 Telefunken Reference Manual (German) Part3

 Telefunken Reference Manual (German) Part4

 Telefunken Reference Manual (German) Part5

 Telefunken Reference Manual (German) Part6

 Telefunken Reference Manual (German) Part7

 Telefunken Reference Manual (German) Part8

 Telefunken Reference Manual (German) Part9

 Telefunken Reference Manual (German) Part10

 Telefunken Reference Manual (German) Part11

 Telefunken Reference Manual (German) Part12

 Telefunken Reference Manual (German) Part13

Osborne 1

89aab638ca04b67e9f6e3ba51b25e337The Osborne 1 is reportedly the first commercially successful portable computer.

Portable is a relative term. Today it seems enormous, it weighs 23.5 lb and despite it having a carrying handle it would be an ambitious person who walked more than a few tens of meters with it but in 1981, when it was released, computers were either three box affairs such as the IBM PC 5150 or large all-in-ones such as the Superbrain. So this was quite an improvement.

If has the popular Z80 processor, the mainstay of the non Apple business computers of the day, a pair of full-height 5.25″ single sided, single density floppy disk drives and a built in 5″ screen.

I got this example in 2008. It is one of the earlier models as you can see it has a the flat ribbon from the keyboard to the main unit and the clips that hold the keyboard in place when travelling are on the side of this unit rather than on the top and bottom as on the later 1A model.

When I first got it there was a sticky return key a sticky floppy drive and a couple of burnt out capacitors, one on the main board and another in the power supply but they were quickly dealt with and now it’s working quite happily.

It’s a nice machine and very capable for the period. The only real drawback in my mind is the disk capacity, at around 80kb it’s really not enough. There is a lot of information on the web about this machine and it’s very easy to get to know.


Telefunken Telecomp 5200

1e25690a7dd68b8a1e763f4bfa7e33c5I recently picked up what was said to be a Telefunken Telecomp5200 machine in an unknown state. I drew a complete blank when it came to finding out about this machine but the price was right and I though worth a punt. First of all there is a big 70s/80s style terminal but the vendor said that this was the system itself – curious. Then a pair of 8 inch disk drives in an enormous box and an analogue joy stick.

There were also some disks and manuals. My fist suspicion was that there was a computer in the disk drive cabinet and the terminal was just that. The disk cab has a 25 way D-type connector often used as a serial connector on systems of this vintage so it could be possible. However, a quick look inside the case shows that it just contains disk drives and a PSU. Hmmm. At this point I should point out that there is a technical manual but it is in German and I am not.5240fe0baaf8218c503b0f734eb295a9

Next I removed the front cover on the Terminal (labelled Terminal-52 on the back – a VT-52 emulator perhaps?) and revealed a large card cage stuffed with cards, CPU RAM, disk controller etc. A big clue is the name Ontel on most of the cards. Haha, Ontel made 8080 based business computers in the ’80s and ’90s and did OEM deals with the likes of Telefunken. So this is most likely a Telefunken badged Ontel OP-1 but which model? I’ll work it out soon.

Next, time to try powering it up. At this point I didn’t have a cable for the disk drive so that wasn’t in the picture yet, so just the main unit to try. I know that these old systems can get eggy over the years and the capacitors in the PSUs go skywards when pressed so I wasn’t taking any chances.
I put the unit on a stool in the garden before giving it some power. I wasn’t scared of physical harm, I just don’t want my kitchen smelling like someone has died. Anyway, flick a switch, there’s a beep and the fan starts. Whoopee – it’s alive-ish. So far I just get a raster and some vertical lines suggesting the size of the character cell. Not a bad start for kit that’s not been on for 20 years. Having read through a few hastily translated bits of the technical reference manual I felt that I knew enough to try and get the floppy drives connected. I wasn’t given an original cable but looking around the back of the card cage and at the drives themselves it looked likely that they needed a 25 Way cable (the manual didn’t say). What about disk drives? Fingers crossed.

Powering up the drives without the cable seemed OK though they did sit spinning. 5 1/4 drives don’t start until they are needed (usually) but I don’t know what 8 inch drives generally do. Switched everything off. Plugged in a cable. Disks on. Main unit on…. Drive light comes on for a bit and then goes off. Whoopee. This is repeatable 🙂 I have since tried a floopy in the drive and get the same behaviour. I can’t get it to boot but I’m delighted to have got it this far.

Changed the caps.

07a86922c133688605321f2f8799bbd8Next I worked my way through the boards in the card cage replacing the electrolytic capacitors on all of the boards, twenty five in all. It’s quite common for old age to get to them and it won’t do any harm to change them. A little more progress. took a closer look at the Telefunken and noticed a burnt track on the logic board. As it goes under one of the logic chips (4 to 16 line decoder) that chip is going to have to come off in order to repair the track.

I’ve been wondering whether or not the machine should put up a short message on boot up. Mine doesn’t and I don’t know if it’s because its broken or because I don’t have the drives attached. An entry at shows the BIOS as only
occupying 256 bytes or memory, enough to boot from floppy. Would they waste some on “Hello and welcome”?. The Amstrad PCW series doesn’t say anything until it has booted so it is a possibility. Scanning in the manual I have started scanning in the German technical manual. I really need some clues and that seems to be the place to start. The plan is to scan it, OCR it and then translate it into English. So far I have about two thirds scanned. The scanner is part of a Brother MFC-J8250 multi-function scanner/printer/copier. It can scan to PDF file on a memory key and works really well.
I’ve found OCRTools on the Apple App Store which can OCR from a PDF file but not only that. It can also translate from German to English at the same time. An amazing little piece of code. Not only does it work really well but it’s incredibly cheap at just £1.99. Amazing.

Retro Tech

I am old enough to remember most of the computer revolution. Back at the end of the 1970s and into the early 1980s computing was interesting. IBM hadn’t won and lost and lots of computer manufactures were trying to make the best set of compromises and steal the high ground.

I have developed quite a soft-spot this old computing technology and have collected a small amount over the years.