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 old-computers.com 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.

Random Orbit 4 – Spindizzy

716aa4a3c46345cd7fbf08f91640a668Progress was slow on Random Orbit 3. This was a big build and was taking too long.

I decided a change was going to have to be made. My Son was fast approaching eleven and here in the UK junior racing starts at eleven.

I though RO3 was going to be a bit too powerful and gnarly for Jack and so I decided to shelve this build and start another, simpler, craft that we could both race.

Now, I am not one to waste a good name and so this one is Spindizzy.

As I now had the moulds and because I really liked the design, it made sense to go with another Outlaw.

A temporary halt

Things have been going very slowly on this build as you can tell.

The plan was to build a gnarly F3 shaft drive and see what I could do in that. However, it has taken too long to get this far and my Son is now 11 and old enough to race. The problem is that I don’t want to put him in a big heavy F3 that he will struggle to control.

So, I’ve decided to put this build on hold a make something he and I can both drive.

Here’s to Spin Dizzy.

Flow straighteners

After fitting the duct to the hull it is time to fit some flow straightener vanes. There are some basic rules here.

  • You need a different number of flow straightener to the number of blades you have. This avoids a nasty beat frequency as all of the blades pass in front of all of the straighters at the same time.
  • They need to have some shape to guide the air from its swirling path off the blade to a flow parallel to the sides of the duct.

I borrowed some moulds to make a set and all was going well unitl I tried filling them with foam for strength and the deformed beyonr recognition 🙁 My old freind Dan came to the rescue wth various vanes he had lurking in his collection. Not only that but he came rounod to help me fit then and also had a pair of rudders. Top man.

The duct

VLUU L200  / Samsung L200The duct is 1M in diameter, quite large for an F3 but I figured it would be about right for this craft. The duct was made by my old friend Dan  who was doing it as a plug for a duct he was building and it was no longer required.

I collected it on a filthy night, strapped to the roof of the car as you can see. You can make out the Kevlar containment area that should hold everything together if a blade lets go and tries to leave through the side.

There is also a flat “plate” running all round the duct. This is to help to keep it circular, particularly where the blades run. It’s quite hard to stop a duct from flexing and as long as the part with the blades in stays circular, the rest can move around a little.

The planing surface

074456a094d63b73f15a88acce6a5b13The Outlaw mould was made ready to take part

Next the various layers of Chopped Strand Matting (CSM), Diolen and Kevlar are cut/torn and laid out on a ground sheet until needed.

36f33050fbe0ffb8392f327294b95707The finished part was popped out of the mould after a few days…

But took an amount of mould with it.


Random orbit 3 – Outline and hull


By now I had a new mould for a top deck/hull and a polished mould for a planing surface that I thought would give me one piece from which I could take another mould.

But, we’re getting a little ahead of ourselves here. I mentioned in the introduction to the Outlaws that I had formed a plan. the plan was to build a new craft on a light, interesting hull. It also involved twin ducts because I like twin ducts and a four stroke engine because I like four stroke engines. I’d still go shaft drive because otherwise engine choice is a bit limited.


The hull.

We’ve seen how the top deck plug was mounted, buffed and a mould taken. The next step was to take a part from that mould.

For reasons unknown I don’t have any pictures of the new mould. Suffice it to say that the plug was pulled of the frame and the mould put onto it. Now I have a mould on a nice frame that can be rocked over at a jaunty angle to make laying up easier.

The layup.

First up, after waxing and polishing comes a couple of layers of gelcoat. I chose a letterbox red. Then a mix of CSM and Diolen. I think I put down one layer of CSM followed by Diolen followed be CSM. It’s been a while, cut me some slack.


The front duct.

The plan was to use two fans, one for thrust, another for lift. The list fan duct is made from GRP as to be expected and was given to me by a freind who has moulds for this kind of thing and a spare duct.

df645fbb4f2efb1831e98d187fc2fd45It was quite a simple matter of finding the centre of the front section of the hull, cutting a big hole and using glue and rivets to hold it in place.

Refurbishing the moulds

Making a new top mould.

85ffe21bfadbd70eecb52846a680a80aFirst, I built a frame to hold the plug. Waxed it well and put on two coats of gelcoat in a colour I was unlikely to use for a hull (this makes things easier later)

9919be69f430d92dcdb01d17403cbe98Next the matting goes on. If I remember correctly 6 layers of CSM but the job is so boring I may have mis-remembered.


The mould for the planing surface.

The mould for the planing surface was made from a plywood frame with a hardboard surface and was in a very sorry state. After several attempts at restoring it I decided to make it good enough to get one part out of it and make a new mould from that.

074456a094d63b73f15a88acce6a5b13The mould above has been filled with pounds of car body filler, painted and waxed.