Erskine Labs and Hartley Electromotives

[M0FYA Andy]

Does anyone know the relationship between Erskine Laboratories Ltd and Hartley Electromotives Ltd?
As far as I can discover on the internet, these were independent companies with no links, yet they both made versions of the same oscilloscope, the Type 13 and Type 13A respectively, used by the RAF and the Army.
Was this oscilloscope designed by one of these companies and then also built by the other? Or was it designed by one of the Ministry organisations and then manufactured by these two companies?

Any ideas, please?

Andy

[ex 2 Base]

Well I don't know any thing about Hartley, but I'm sure Erskine would have designed and built their own equipment. Erskine were always ahead of their time, no longer in existence and have been taken over lots of times. After being taken over for the first time about 50 year ago, they dropped most of their products, but continued make large power supplies, cabinets and pcb, then got into UPS. Now trade under the name of Dale Power Systems.
I know several of former Erskine employees and will ask for you when I next see them.

[Radio Wrangler]

Dale power systems as in a generator manufacturer I remember outside Filey?

David

[turretslug]

Wasn't it part of some military contracts with a primary supplier that they were to supply production documents to a chosen secondary supplier (there may have been a bit of arm-wrestling over exactly who in particular cases) in order that the item concerned was available from both sources? Sometimes, there may have been concern over contractor competence, or ability to fulfill chosen quantity in desired time, or perhaps simply to guarantee security of supply- there must have been a few hard lessons from e.g. WW2 that a dangerous bottleneck/shortage could develop if a single-sourcing factory was bombed or suffered a disastrous fire.

[M0FYA Andy]

It could well be, that's the sort of thing I'm thinking may be the case, but is there any evidence to prove it?

[David Simpson]

Hartley Electomotives of Shrewsbury eh. Their 13A 'scope - a big heavy beast & & one the most frequent visitors to my repair bench during my RAF T/Eq days. There has been a heap of "banging-on" by myself & others over the years. See "Search".
Hartley also produced the 13A's replacement - the CT436, but Solatron also had a sub-contract, if I remember.
Hartleys huge(to me) factory was close to the A49 going north out of the town. 'Twas imprinted into my memory since I was a babby, as I'm half-Salopian & my mother's family home was just about 9 miles further up the road to Prees.

Regards, David

[WME_bill]

Hartley 13A oscilloscope.
For MOFYA Andy. I have also puzzled for years about who designed the 13A. It was a curiously outdated design when it was produced in mid 1950's, with an old tube, the Cossor/Etel 09D / CV1596 as used in the pre-war Cossor 3339 / 339, at a time when Cossor were using a more modern flat faced tube 89D in their 1035.
The 13A also uses the Philips video output pentode AL60, which Mullard classified as obsolete by 1956.
A similar valve (42SPT) had been used in the Cossor 3339 which was rejected in the war as difficult to get and the 807 substituted to give the Cossor 339, though with a much poorer performance.

I have seen an apparently undocumented later production modification to the Hartley 13A to fit a modern flat screen tube, Cossor 89D / CV2193, with a 6v heater, which meant the EHT rectifier was changed to two STC sticks K8-45 instead of the SU2150 / CV1120 to free the extra heater voltage winding.

I suspect Erskine were just the MoD second source manufacturer. I have always felt it was an Army design rather than Naval/RAF. But perhaps it was an Erskine design.

Hartley were general electrical / radio subcontractors. Started in 1939 and had been most successful immediately after the war. They made with housing wiring looms, tape recorders and radio and test equipment subcontract manufacture. I don't believe they had a design team until they absorbed Baird Television in 1954. Finally sold on and business closed down 1972.

For David Simpson, I think you will find that the CT436 (CD1017) of 1962 was a Solartron design, as it is uses very similar circuitry to the Solartron CD1014 of 1960-61. I understand it was the same design team, led by Ron Kettlewell, who shortly after went off to start Telequipment. This was about the time of the Solartron move from Thames Ditton to Farnborough and the subsequent sell out to Firth Cleveland in 1960 and to Schlumberger in 1962.
If you compare the Solartron CD1014 series with early Telequipment you will see many of the same ideas.

I suspect that Solartron was so busy with other scopes, the CD1014 and CD1400 sold well, digital voltmeters and automatic test equipment that most of the CT436 scopes were manufacturerd by Hartley (HET). Partly this was MoD rules anyway, as MoD always seem to have required two manufacturers. The tube was an Etel design, but then also made by GEC/MOV and Mullard (DHM9-11, 3AZP31, CR131) . The valves lots of makers.
wme_bill

[Craig Sawyers]

Ah - the boat anchor Hartley 13A. That was my first oscilloscope aged 14. They were selling new-old-stock ones back in 1970 in adverts in PW.

Performance was laughable by today's standards, but it was built like the proverbial outhouse. Came with a front cover that contained connecting leads, and a cathode follower probe.

Forget who I eventually sold that beast to.

Craig

[Radio Wrangler]

Fascinating! Thanks, Bill.

I always wondered about the 13A, seeing the adverts in the usual magazines. £13/19/6 seems associated with the memory. The illustration was awful. Nothing could be made out of the panel and controls. You could tell it was an oscilloscope but that was all. I never saw one in the flesh until at a radio rally in the eighties.

I'd been given a Cossor 339 that was being binned by the school and stripped it for the EHT transformer. It had the SU2150 rectifier, but I used strings of BY100s to bias my shiny new VCR97. Finding out the 13A used the 09 CRT tells me that if I had saved up and bought one, it would have been a bit of a step backwards.

It was a very old-fashioned scope for production in the fifties, and test equipment manufacturers have always been strongly competitive, so the 13A could only have come about through government control. Just think that Howard Vollum must have been getting going around the same time, unknown to us in the UK.

David

[David Simpson]

The 13A, like the AVO7, the Marconi 65B, & the Marconi TF144G, were the mainstay of RAF Radio Schools from the 50's through to about 1970. Basic introductory test equipment for cack-handed Boy Entrants, Apprentices, National Service & other adult trainees. I never realised just how much damage this stuff suffered until I ended up in the repair section at Cosford(No 2 School) in '66. This would be the reason why much of the test equipment was sub-standard rejects from RAF Henlow, Marconi's & Hartley's, etc. Hundreds of items came through our section per month & "Christmas tree-ing" was a common practice. I hated 13A's back then, & I wouldn't touch them with a bargepole now. However, I'm happy to be a proud owner of a working CT436, which only cost a fiver a few years back.
Incidentally, having restored a pre-war Cossor 3339, & a wartime 339, I reckon they were the better D/B 'scope.

Regards, David

[Craig Sawyers]

I agree entirely about the 13A. Even to my, at that stage naiive eyes, it was a strange and very heavy animal. There were two vertical amplifiers, which you could cascade to get higher sensitivity. But the already low bandwidth became even lower. And because the timebase was not calibrated (well, nothing on the scope was...) there were crystal marker pips to give the horizontal sweep speed.

But inside - wow. The cable bundles were the nicest example of traditional cable lacing that I can remember. And all the valves had retainers.

It was also my first experience with paper caps being leaky. I tried out the cathode follower probe on my newly completed RF generator, using Germanium transistors. Pow. Killed it stone dead.

I was going to say happy days. But with that scope they weren't.

My second scope was the Solartron CD1400 with a selection of plugins. That was a much more serious beast, recovered from a pile of stuff that was destined for the skip at Southampton University. That did me for 20-odd years, before I got the Tektronix collecting bug.

13A data is here https://www.thevalvepage.com/testeq/hartley/13a/13a.htm as is the CD1400 and lots of other classic gear https://www.thevalvepage.com/testeq/scope.htm

And Tektronix gear was a rabbit hole - pass the medication would you?

Craig

[ex 2 Base]

Back again Andy, re Erskine CRO. Well on checking this morning, I found out the only person who would have known is no longer with us.Dale Generators who used to be at Gristhorpe a village near Filey is also no longer with us, closed down about 20 years ago. Dale took over Erskine about 45 years ago and the whole lot has had numerous take overs in recent years. Dale factory has gone and Dale Power Systems now occupies Erskine premises.

[Chris55000]

Hi!

I was given a 13A in my young days and even when I left school I could barely lift it!

The one I had had a graticule that looked like a sheet of graph paper and the circuit diagram was silver–finish on a black background on thin metal plate, so often used for front panels of that era!

I was amazed how clear and accurately done those tiny figures and letters on the diagram were produced, they were a hand–lettered style, not a Uno stencil!

Chris Williams