Vintage Digital

[wireman]

Came across this video

https://youtu.be/jgS_UhDCn1s

Most interesting, I didn't know that you could purchase digital test gear in this era (1957).

[factory]

The 524A dates back a bit further to 1952; https://www.hpmemoryproject.org/wa_p..._a_page_11.htm
Mil version of the 524B here; https://www.youtube.com/watch?v=3ka1wwvex5o

Presumably prices will go up now Carlson has done a video, not that any of them are easy to find over here.

David

[The Philpott]

I chanced upon a website giving details of the history of digital displays, cannot find it now- (Fran Blanche probably mentioned it in one of her videos)

Quite apart from Nixie, Nimo, Numicator, Numitron, i saw a more mundane set-up in a US made valve voltmeter of this sort of vintage that employed 10 acid etched glass slides per digit, toplit by one of ten lamps- so a 5 digit display required 50 lamps.

Dave

[TonyDuell]

Those '10 slides with etched numbers and a lamp for each' made it into the transistor and IC era, albeit with perspex-like plastic slides. Normally there were 5 bulbs at the top of the unit and 5 at the bottom to save space.

There are a couple in my Trend test set 1/4 (DTL logic chips) and by chance I bought a little Racal 4-digit frequency counter last week (discrete transistors) with them. The previous model of said instrument (I have one with more digits) had a column of 10 bulbs behind a panel with numeral-shaped cutouts for each digit.

There was also a thing with 10 bulbs at the back, each with its own digit-shaped mask and projection lens and a ground glass screen at the front that the digits were projected onto. I think I have ome somewhere but just the display unit, not a complete measuring instrument that uses it.

[The Philpott]

Yes Tony, i have 3 miniature examples of the projector displays in your last para.- usually called 'In Line Displays' by Counting Instruments Ltd. Superb miniaturisation, they remind me of microfiche and also the little victorian microphotograph viewers.

https://www.vintage-radio.net/forum/...ad.php?t=75707

(Mine are a lot smaller than those featured- two of them amount to the size of a tictac box.)

Dave

[factory]

Originally Posted by The Philpott

I chanced upon a website giving details of the history of digital displays, cannot find it now- (Fran Blanche probably mentioned it in one of her videos)

Quite apart from Nixie, Nimo, Numicator, Numitron, i saw a more mundane set-up in a US made valve voltmeter of this sort of vintage that employed 10 acid etched glass slides per digit, toplit by one of ten lamps- so a 5 digit display required 50 lamps.

Dave

Possibly one of these two websites?
https://www.industrialalchemy.org/tubelist.php
http://www.decadecounter.com/vta/tubelist.php

The top-lit/edge-lit displays were used in British test equipment too, there are even some in a vintage BBC outside broadcast vehicle with custom plates.


David

[The Philpott]

Aha, found it again by chance, the YT algorithm threw up one of his videos- (mike's electric stuff) electricstuff.co.uk

Dave

[newlite4]

I can remember using very similar counters to this in the 80s and 90s made by RACAL in the 60s. Although fully transistorised, the same decade lamp strips were used. As for the engraved glass plate decade displays, I remember in the mid 80s installing a Solartron HS7-3D analog computer circa 1968 which had an array of those for the readout.
Neil

[MotorBikeLes]

If i remember correctly, the Racal counters you are probably referring to used capless lamps, NOT neons. Same layout, 10 lamps in each vertical array.
Les.
Les.

[Radio1950]

Originally Posted by MotorBikeLes

If i remember correctly, the Racal counters you are probably referring to used capless lamps, NOT neons. Same layout, 10 lamps in each vertical array.
Les.
Les.

Yes - they were.
And those Racal counters, and 30 MHz Prescalers, were very good in their time.

[PETERg0rsq]

I have a copy of a Racal catalogue from 1961, which shows many different digital counters, such as mentioned above.

Including SA505 which was 10MHz direct reading using "in-line projection displays", mechanical printers at up to 60 measurements (Prints) per minuit, converters to use with calculating machines, as well as inline digital readouts.

Also very interesting is a very early A/D converter, that converted any counter into a Digital DC voltmeter.

Catalogue also includes some good descriptions on how these instruments worked.

Catalogue is marked from www.electrojumble.org.uk

http://www.electrojumble.org.uk/DATA..._Inst_1961.pdf

[Bill]

I have a Racal version of this HP, full of twin triodes, virtually same display,size & layout.
I think it predates the HP by about 5 years. I don't know if it still works, it was ok about 30 years ago!

[factory]

The HP 524A is featured in the Jan 1951 Journal https://www.hpl.hp.com/hpjournal/pdf...Fs/1951-01.pdf
And the HP 522B counter is in the Nov 1952 Journal https://worldradiohistory.com/Archiv...PJ-1952-11.pdf

The Racal one must be pretty hard to find too. Try not to mention what it contains, last thing we need is more counters being pillaged for the parts.
The oldest Racal counter I have is the transistorized SA505A, it's not in the best of condition, but I hope to repair it one day.


David

[avocollector]

I love the older digital meters with nixie and similar displays and have several. At the time whne still a child (60's) it seemed so utterly furturistic - remember seeing the sinclair black watch kit with it's red led display ads in Pratcial Eletronics and really wanting one. I later heard it was real fun to actually fit the guts into the case!!

I quite enjoy Mr Carlsion's lab - can appreciate it must be annoying when everybody who has something he talks about then thinks it must be valuable, but this happens in all sorts of areas - I've seen someone recently try to get $150 for a Heathkit transistor tester which was just a bastic passive one - mine cost me just $10 but did not have the case!! As for anyone wanting a 12AU7 or 12AX7 valve - well they are now the target of Guitar valve amplifier enthusiasts questing after 'tone' and only available for silly prices. Of course there are also the dreaded 'tone-sucking capacitors' in modern electric guitars only to be remedied with $80 Russian oil-filled paper capacitor replacements - LOL.

[Chris55000]

Hi!

Presumably prices will go up now Carlson has done a video, not that any of them are easy to find over here

T & M prices also have a habit of rising alarmingly very rapidly when manuals or circuit diagrams get found as well, in my experience!

Chris Williams

[markfff]

Originally Posted by The Philpott

Quite apart from Nixie, Nimo, Numicator, Numitron, i saw a more mundane set-up in a US made valve voltmeter of this sort of vintage that employed 10 acid etched glass slides per digit, toplit by one of ten lamps- so a 5 digit display required 50 lamps.

I had one of these many years ago Dave, made by a company called Cubic (I don't remember the model number). It was a true boat anchor, about a foot tall, the width of a rack, and very heavy. The display and autoranging were done using Ledex solenoids to ratchet several rotary switches into position. It made quite a racket, but was pretty fascinating to see it in operation. I wish I still had it, but at the time I had to let it go for lack of space.

[Dekatron]

@markfff: Thanks for mentioning the Cubic model, I Googled some and found an instruction manual with circuit diagram here: http://www.dvq.com/docs/cubic-v45/cubic-v45-ocr.pdf (there is also a non-OCR version http://www.dvq.com/docs/cubic-v45/cubic-v45.pdf) and that helped me a lot since I have an earlier valve driven voltmeter model from Non-Linear Systems, the Model 64, which I haven't been able to find a circuit diagram nor an instruction manual for. I was sent an article describing the NLS Voltmeters that showed some of the design but the Cubic manual contained information on maintenance of the stepping relay switches which will be very helpful when getting my NLS up and running again. This video shows the selectors and display of an NLS voltmeter running: https://www.youtube.com/watch?v=OIATKbSkYxw

I also have other types with other displays and one type I like is the moving coil design Digivisor Mark II: http://www.electricstuff.co.uk/venner.html

[markfff]

Originally Posted by Dekatron

I Googled some and found an instruction manual with circuit diagram here: http://www.dvq.com/docs/cubic-v45/cubic-v45-ocr.pdf

Thanks for the memories Martin, I spent hours playing with that Cubic DVM and figuring out how it worked. The model I had may have been a bit older, it had three modules in a case made for rack mounting. The top module had the display and looked like that v45. The other two modules were the same size, and as best as I can remember, one seemed to be for signal processing -measuring AC, and the other a control module. I remember it having tubes, but there may have been solid state devices as well. I've lost a lot of the details to ageing gray matter.

Originally Posted by Dekatron

I also have other types with other displays and one type I like is the moving coil design Digivisor Mark II: http://www.electricstuff.co.uk/venner.html

I like this one, an analog driven digital display. Never seen that before

Mark

[emeritus]

We had one of those Racal glass slide counters in the lab at Plessey in the early 1970's. Large, easy to read digits.

I only encountered HP linear display instruments with displays as per the OP's video when they had a clearout of obsolete stuff that employees could buy: I think they were priced by weight at scrap metal prices! One of my colleagues bought several of them, which he promptly sold to a shop in Lisle Street, making enough to finance his next holiday in Spain.

[factory]

Advance had digital counter using analog panel meters scaled 0 to 9.


As did Venner.


P.S. Pictures were saved from old auction listings, I don't have either of these.

David