Tektronix 4051: How did it work? - Page 1
Forum section: electronics / general

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 08, 2017, 12:15:53 am
content: Whilst trawling the Vintage Computing ads on ebay a thought came into my head...... Tektronix 4051I remember seeing the Tektronix 4051 as a demo in a trailer somewhere in the UK during the late 70s... it was the most amazing thing I had ever seen and probably one of the reasons I ended up doing what I've been doing for a rather long time now.... but it got me to wondering.How does the screen actually work? The drawing is quite slow but the parts of the screen that have already drawn stay drawn beyond what you would think is a reasonable persistence time.Here's a similar display as an examplePSNo sign of any Tektronix on EBAY. Just too niche I guess.

author: rfeecs
author_rank: Frequent Contributor
timestamp: March 08, 2017, 12:25:11 am
content: They used storage tubes:https://en.wikipedia.org/wiki/Storage_tubeThe same type of tube used for analog storage oscilloscopes.I remember seeing those terminals back in the 1970s. Tektronix had a whole line of graphics terminals and crts:https://en.wikipedia.org/wiki/Tektronix_4010They were basically vector graphics displays, but they had a "flood gun" that would keep the image visible.One problem was no scrolling. When you got to the end of the screen it would wrap around back to the top. You had to clear the screen for every page displayed. It was sort of like an electronic etch-a-sketch.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 08, 2017, 12:29:39 am
content: Thanks.I should really have googled a bit harder.... but it's interesting stuff.I also foundhttps://en.wikipedia.org/wiki/Tektronix_4050

author: TerraHertz
author_rank: Super Contributor
timestamp: March 08, 2017, 12:21:33 pm
content: Ah memories.Back in my 1st year of uni (Elec eng), the architecture faculty bought a Tek 4014. Which was the biggest storage tube vector display Tek made. The uni had just recently bought a CDC Cyber 6000 mainframe. The only real computer on campus. They had to knock a wall out of the side of the elec eng building, several floors up, to install it.Anyway, I managed to wangle some time on the Arch. Dept. 4014 display terminal. Was only a beginner programmer, in FORTRAN, so the demo I did was very simple - a simulated rubber sheet, (mesh) you could grab points on, stretch, then release and watch it bounce. With quite slow screen redraw! But it was fun.So even after personal computers came out, and I'd been using them for years, that old 4014 was one of those 'childhood dreams' of owning one. Despite being quite useless.Much later, I was working for a company in Redfern that did CAD software and hardware for commercial embroidery. One day one of the company owners mentioned they had an old Tek 4014 in a nearby storage space, that they used to use for the embroidery stuff, years ago. They were about to throw it out, did I want it?Ha ha... I still have it.The sad part is, it was working then but isn't now. That was before I had a real workshop or big house. So it got stored in a small fibro garage that pretended to be my workshop at the time. And... one time I'd left the front panel off the circuit card frame for a few days. Then noticed an odd thing on some cards - sort of wet looking. Yep, a cat had pissed on it.I washed them very well, dried out, seemed like they would be OK. And then.... a few days later, after I was sure it was well dried, I turned it on. But forgot I hadn't pushed all the cards in. The so-called workshop had poor lighting, so it wasn't obvious.The result was 2 or 3 fuse resistors in the upper section (screen drivers, analog amps) blew.Partly this stupidity was due to being so busy those days. Family, work, part time uni course, and some other dramas. Then we started on a new house project. I never got time to look at the 4014 again. Now it's just an artefact in my museum (junk) room.Also dammit. I had the service manual, and used to keep it inside the unit. That was before I had a real workshop, discovered ebay, and started buying other Tel & HP gear, and the manuals. Now I have a considerable library of manuals... but I can't find the 4014 one. I remember one day (years ago) taking it out of the machine, thinking I should keep it somewhere better than that. No idea where that was, and I just spent an hour searching. Oh well, hopefully it will turn up.Hey, guess what processor it uses?(Those who know the answer immediately, don't spoil it.)Edit: PS. This is definitely the 2nd-most nicest piece of equipment I've blown up through carelessness. The best one was a Tek 7104 1GHz scope. Fumbled the EHT lead while disconnecting an in-line HV plug, to discharge CRT to the frame. Result - discharged the CRT to the deflection amps board. Fzzzt! The one covered in unobtainium GHz Tektronix unique ICs.

author: Howardlong
author_rank: Super Contributor
timestamp: March 08, 2017, 12:41:10 pm
content: I used the dumb terminal version, the 4010 series, of these in the early 80s, with a Prime backend I think, although it might've been an ICL 1904, it was a long time ago and it was during a switch from the ICL to the newer Prime.I spent hours making 3D XYZ plots of functions, with the 3D to 2D perspective conversion and hidden line removal done in my software (Fortran 77). I remember the resolution seemed breathtaking to me at the time even though it was monochrome.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: March 08, 2017, 12:49:32 pm
content: These threads make me wish I was older than I amI rather like the principle of the Tektronix vector displays. When I was going through The Art of Electronics Student Manual many years ago in the 1990s, I built the whole 68008 based SBC in it with two D/A converters. This was used to crudely draw some shapes on the screen of my scope in X-Y mode. I LONGED for persistence on that rather than having redraw loops and the associated overshoot, scan speed and timing problems. It wasn't until over a decade later I even became aware of the existence of storage tubes.

author: David Hess
author_rank: Super Contributor
timestamp: March 08, 2017, 01:50:40 pm
content: Check out Tektronix Circuit Concepts - Storage Cathode-Ray Tubes and Circuits which isavailable herefor details on how direct view storage CRTs work.Quote from: Howardlong on March 08, 2017, 12:41:10 pmThe resolution in lines is limited by the CRT spot size which is not great on a storage CRT but in practice, monochrome vector CRTs were often driven at much higher resolutions in a useful way than their spot size will support; the various early Tektronix DSOs with vector displays operated at almost 300dpi (10 bits) and look very smooth compared to later DSOs which used raster CRTs and modern LCDs when used with high resolution data.

author: coppice
author_rank: Super Contributor
timestamp: March 08, 2017, 02:08:14 pm
content: Quote from: Howardlong on March 08, 2017, 12:41:10 pmI used these 4k resolution Tek screens in the 70s, and finally I am finally back to using a 4k screen today. In between was a long sad period of tolerating rather poor resolutions.

author: nfmax
author_rank: Super Contributor
timestamp: March 08, 2017, 02:56:10 pm
content: I used Tek 4051 and later 4052 'personal computers' with storage screen graphics in my postgrad years 1978-1981. One of my fellow researchers was Japanese, and managed to program the thing (in BASIC!) to display Japanese (Kana?) characters, which was totally mind-blowing at the time. A few years later I was using a 4010 graphics terminal hooked up to a PDP 11/45 running DATS signal analysis software, and then using an HP modular storage-tube display monitor (same idea, different patents) built into a boatanchor thing including an LSI-11/2 and data acquisition hardware. Anyone out ther know what an MSDA was?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 08, 2017, 03:40:02 pm
content: Quote from: SingedFingers on March 08, 2017, 12:49:32 pmNever wish that. There are wonders to come!

author: iainwhite
author_rank: Unknown
timestamp: March 08, 2017, 03:58:56 pm
content: When I was at university (1979-82) I remember writing a Fortran program to plot wire-frame models on a Tek 4010 terminal.Edit: a bit like this:https://en.wikipedia.org/wiki/Tesseract

author: rstofer
author_rank: Super Contributor
timestamp: March 08, 2017, 04:00:43 pm
content: I still have my 4006 - the junior model, all I could afford at the time. I haven't taken it out of the box in 30 years but I still have it!It was a great display to use with UCSD Pascal Turtle Graphics back around '80.

author: David Hess
author_rank: Super Contributor
timestamp: March 08, 2017, 04:31:43 pm
content: Quote from: coppice on March 08, 2017, 02:08:14 pmIt took LCD monitors 10 years to catch up to my last CRT monitors and they still do not look as good. LCD DSOs have not caught up to my 300dpi vector CRT DSOs yet.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 17, 2017, 08:15:24 pm
content: Only the dumb terminal...eBay auction: #122387748065I must resist.... I must resist.... I must resist....

author: coppice
author_rank: Super Contributor
timestamp: March 17, 2017, 08:19:36 pm
content: Quote from: NivagSwerdna on March 17, 2017, 08:15:24 pmOh, don't get one of those. It has the small screen. Wait for a 19" 4014, or the 26" one.

author: james_s
author_rank: Super Contributor
timestamp: March 17, 2017, 09:45:37 pm
content: Those things are amazing!I love CRTs, especially vector displays, and the analog storage is even cooler. Great space age styling too.

author: mike40
author_rank: Newbie
timestamp: March 22, 2017, 12:58:14 am
content: . . .I couldn't resist! . . . .its sitting in my living room now . . . when powered on just gives a green glow on the Screen, I think the tube is OK - It will hopefully be some fun trying to fix it, I got a technical manual online which is quite detailed . . I think £112 was a good price, it belongs in a Museum really!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 22, 2017, 01:32:48 am
content: If I'm ever in, I'd like to see it!

author: TerraHertz
author_rank: Super Contributor
timestamp: March 22, 2017, 04:25:44 am
content: Quote from: mike40 on March 22, 2017, 12:58:14 amCool. The tube is much like a storage scope tube. There's a 'persistence/brightness' control (turn it up too high and the 'on' areas bloom out so the entire screen glows), and an 'erase flood' gun (that also makes the entire screen glow when it's active.) I suppose faults in either circuit could make the screen permanently glow.Do try sending it some serial text, and seeing if there's any sign of it drawing anything. It should reset at power on to draw received characters at screen top left. There's no microprocessor at all, just discrete logic. Baud rate will be clock selection jumpers.

author: boffin
author_rank: Unknown
timestamp: March 22, 2017, 05:15:25 am
content: we had a 4010 (or maybe 4012) hooked up to a VAX11-780 in college. I wrote a library to make it work with some textbook about computer graphics for it.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 22, 2017, 11:30:03 am
content: Quote from: mike40 on March 22, 2017, 12:58:14 amWell done! It give me a warm feeling that someone is looking after it. I might have to come and visit sometime if you get it working.

author: mike40
author_rank: Newbie
timestamp: March 22, 2017, 01:11:04 pm
content: Thanks all - Yep the previous owner tried to send serial data but to no avail - The Keyboard LEDs don't light up either - Yep if the earlier poster who repaired one has any of those repair documents it would be great if you could post them . . .

author: Brad-4051
author_rank: Newbie
timestamp: November 03, 2017, 12:05:05 am
content: Hi - for anyone following this thread interested in "playing" with a Tektronix 4051, I have written an extensive simulator for it. Runs about 40 of the BASIC commands and simulates the graphics reasonably well. It runs on Windows as a standalone application. There is a demo of it on youtube, and a sample of some graphics is attached. Contact me to get a copy. I also have a Tek 4051 BASIC facebook page - feel free to ask to join.