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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 28th Jul 2021, 10:13 pm   #1
AngelaD
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Question Hazeltine 1421. Now offered FOC.

Hi all. I work.in a school and I'm sorry to say I know nothing about computers, old or new. Whilst having a clearout in IT we have found a very old computer and don't know what to do with it. The screen is cracked sadly and I've no idea if it still works. I'm curious for any info about it (age, etc.) and suggestions of what to do with it. I have picture but not sure how to.post it on here.
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Old 28th Jul 2021, 11:51 pm   #2
paulsherwin
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Default Re: Hazeltine 1421

It's an early 80s computer terminal, not a standalone computer. These were normally used with minicomputers. It was very unusual for even very well endowed schools to own minicomputers (they cost 6 figure sums, and that's 1980s pounds) so it may have been acquired following a clearout by a commercial company at a later date.

If it's significantly damaged it's pretty much WEEE I'm afraid.
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Old 29th Jul 2021, 12:06 am   #3
SiriusHardware
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Default Re: Hazeltine 1421

Hi Angela - we are always curious about such things, so to post a picture:

-Hit the 'Go Advanced' button below the post editor box, that will open an editor with more features including the facility to attach images.

-Compose your message explaining what the image is of,

-In the icons above the advanced message editor, top row, left of centre, find a paper clip (attachment) icon and click that.

-In the 'Manage Attachments' box which opens up, click one of the 'Choose File' buttons and browse to the file you want to attach, click on its thumbnail in the browser and click 'open'. This puts the image in the upload queue.

-Click the 'upload' button in the lower right of the 'Choose File' box. There will be a delay of a few seconds while the image uploads and is processed by the forum.

-Return to the message editor window and click 'Preview Post'. If you have successfully attached the image it will be shown attached to the preview.

-Remember to click 'Submit Reply' to actually submit the post.
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Old 29th Jul 2021, 12:30 am   #4
JohnBHanson
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Default Re: Hazeltine 1421

Just to be more helpful - this would have been a computer terminal with 24 lines of 80 characters wide of text on the display. It has two 25 pin connectors
on the rear one of which is for connecting to a computer either directly or via a modem. The other is for capturing or printing text called aux.

It would use a slightly unusual set of codes based around either tilde(~) or
esc as a lead in.

The 25 pin connectors are either rs232 which is a standard still in use or 20mA which is an older standard that teletypes used.

You can get the manual from the network if interested (try bitsavers). It
could be used with a liunx system via a 9 pin rs232 interface with the correct lead.

It would have a white screen.

If damaged be careful it has very high voltages inside (eg 25000 volts).
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Old 29th Jul 2021, 5:11 pm   #5
TonyDuell
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Default Re: Hazeltine 1421

There are a fair number of statements made so far that I disagree with.

Yes it's a computer terminal, rather than a complete computer. Such terminals were used with some microcomputer systems, not just minicomputers. They were also used/desired at the time by people making their own microcomputers, it is a lot easier to add a serial port rather than a keyboard interface and video display system. That might explain why a school would have one. Alternatively, it could be used with a modem to link to a remote computer system, at the time some schools got time on such a timesharing computer, they would call it up with the terminal/modem to run the student programs.

That said, by the 1980s, a small minicomputer system cost a low 5figure sum. And there were surplus ones about which a school might have obtained.

It most certainly is not WEEE if it needs repair. There are plenty of people who run minicomputer systems at home as an enthusiast. Just as there are people who run 405 line TV sets, or WW2 military radios. Some of these enthusiasts like to use the 'real' terminals rather than a PC running a terminal emulator.

If the screen is broken, then it'll need a new CRT. These CRTs are fairly 'generic' you can get one of the right size and deflection angle to work with a few electrical modifications. When I needed a replacement CRT about 35 years ago for a rare computer terminal, the easiest and cheapest way to get one was to get a cheap portable black and white TV and extract the CRT from it. That may still be the case actually. Just don't wreck a rare TV for the tube.

If this is a monochrome terminal, and I am pretty sure it is, the highest voltage will be around 12kV (not 25kV) as in a monochrome TV. It's at a fairly low current too. I feel the most dangerous voltage in such units is the mains (or rectified mains if it uses a switch-mode PSU).

As for the character codes, unless it is a block mode terminal only (and I don't think it is), it will display text if you just feed it the ASCII codes, similarly the keyboard will send ASCII out of the serial port if you press a key. The command sequences (starting with <esc> or whatever) are used to position the cursor, select special character sets, etc. You deal with that after you've got the rest working.
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Old 29th Jul 2021, 5:23 pm   #6
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Default Re: Hazeltine 1421

Would you consider rescuing it, Tony? Even if the tube is wrecked it may have some useful parts which might be better saved than jettisoned to WEEE. Without seeing an image of it it's difficult to know if it is actually the tube which is cracked or just an overall protective cover.

I don't know how mobile you are but it doesn't look too bad a drive from BH to Portsmouth (M25, A3) - but then I have not driven in that area for many years now, so I'm not speaking from recent experience.
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Old 29th Jul 2021, 5:32 pm   #7
TonyDuell
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Default Re: Hazeltine 1421

If it was local then I would consider rescuing it. I even have a suitable spare CRT in stock.

But I don't drive, and making a trip to Portsmouth is a bit much on public transport, not to mention getting the thing home again.
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Old 29th Jul 2021, 6:27 pm   #8
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Default Re: Hazeltine 1421

Tony, a Vax 11/780 cost 300k in 1979. Comparable systems from people like Data General and Norsk Data were a bit less, but not by much. I don't think the Bash Street Kids would have been using this sort of stuff.

Terminals themselves cost 4 figures.
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Old 29th Jul 2021, 6:36 pm   #9
JohnBHanson
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Default Re: Hazeltine 1421

Look here for the manual. Yes it will do ascii
http://www.bitsavers.org/pdf/hazeltine/Hazeltine_1420/
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Old 29th Jul 2021, 6:38 pm   #10
TonyDuell
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Default Re: Hazeltine 1421

You have picked just about the largest minicomputer of the time. How much did something like a PDP11/03 cost?
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Old 29th Jul 2021, 6:54 pm   #11
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Default Re: Hazeltine 1421

I was at school, unluckily for me, just before 'Computing' seriously became a 'thing' in schools. At that time it tended to be the exclusive preserve of the maths department and all they usually had was one terminal much like this one, talking to some remote system most likely in a university somewhere.

Not long after I left, schools were flooded with BBC model Bs, and the rest is history.

Skidding back on topic, Angela, if you are still with us, we have a good idea of what that unit is, but we'd like to see the condition yours is in, especially with respect to the screen damage. If you have time to post a photo or two that would be appreciated.
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Old 29th Jul 2021, 7:02 pm   #12
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Default Re: Hazeltine 1421

I don't know offhand how much PDP11/03s cost, but I would guess maybe 40k. We tend to forget how much this technology cost back then. Some of the better endowed public schools were running PDP-8s, but even universities struggled to find the budget for modern kit. I remember Royal Holloway's computer teaching was based on a PDP-8 in the mid 70s, and that was a London University college. Oxford University Computing Service installed its first minicomputer in 1979 (a VAX 11/785 IIRC) to supplement their very unreliable ICL2980 mainframe. They were still trying to use 110 baud teletypes at the time, because cursor addressable terminals cost so much.
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Old 29th Jul 2021, 7:03 pm   #13
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Default Re: Hazeltine 1421

Here's an 80's advert for one. I don't recall ever using one but they were quite common like VT100's.
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Old 29th Jul 2021, 7:41 pm   #14
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Default Re: Hazeltine 1421

Hazeltine were one of the well known independent terminal manufacturers, along with Lear Siegler who made the very popular ADM3A. These companies suffered because their hardware didn't support DEC's proprietary standards for cursor addressing and line drawing graphics, and DEC increasingly dominated the 80s minicomputer market.
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Old 29th Jul 2021, 7:42 pm   #15
JohnBHanson
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Default Re: Hazeltine 1421

There was a haz 1522 that was vt52 compatable and hence suitable for DEC machines eg PDP11/VAX.

Some of the early PDP machines only had a 20mA interface which was designed
for teletypes. Latter RS232 interfaces appeared..
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Old 29th Jul 2021, 7:57 pm   #16
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Default Re: Hazeltine 1421

I have a Hazeltine 2000 somewhere, very classy machine! I'm sure there are collectors of vintage terminals out there, though it doesnt mean they're worth much.
Our local authority 6th form college had a PDP11 clone (systime) and rooms of various terminals, did my A-Level on it.
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Old 29th Jul 2021, 8:19 pm   #17
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Default Re: Hazeltine 1421

Quote:
Originally Posted by Keith956 View Post
Here's an 80's advert for one. I don't recall ever using one but they were quite common like VT100's.
That`s a 1420 - it had the most unreliable keyboard I`ve ever used.

Much cheaper than a VT 100 though, If I remember correctly.
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Old 29th Jul 2021, 11:56 pm   #18
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Default Re: Hazeltine 1421

Please do post a picture as per Sirius post - we can probably locate a museum or collector in your area who would help - whatever happens do not send it to WEEE these things are getting rare.
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Old 30th Jul 2021, 10:02 am   #19
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Default Re: Hazeltine 1421

"Screen is cracked" could equally well mean that the plastic cabinet is cracked, which is probably trivial to sort out. Surely it's vanishingly unlikely for a CRT to survive with a crack in it, unless someone's knocked the neck off it and then hit with a brick.

Regarding computer terminals in schools, I was at secondary school as the computer revolution was taking off. We had a room full of BBC Micros very early on, mostly due to being round the corner from the Acorn headquarters, but there were also sundry other machines which had been donated. I remember a couple of ASR33 Teletypes (we had fun getting those to talk to each other) and a peculiar dot-matrix printing terminal branded "Prime computer". There was a random CP/M machine (a Comart Communicator) which used a substantial amber-screen serial terminal. So these things were to be found in schools, even if they weren't being used to remote access minicomputers and mainframes. I'm not sure if our school ever had that capability - probably not.

A picture would reveal a lot!

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Old 30th Jul 2021, 12:12 pm   #20
paulsherwin
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Default Re: Hazeltine 1421

Prime were another minicomputer company.

https://en.wikipedia.org/wiki/Prime_Computer
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