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Hi Les,

Thanks for the informative reply! First - serial numbers, not on the back but? yes, stamped into a lower chassis rail is "666." (that number, I hope, is not an omen!) and hand written and varnished over on the power transformer is "58666". Until I find out different I'm assuming 58 could be the year and 666 the serial number. If so then that would probably make this one of the last 'pre-facelift' Serviscopes produced and whether they called it an S31 at that point I don't know.

It is very similar in physical construction to an S31 and the only schematic differences I've spotted so far between the S31 and what I see in front of me are: No series anode resistors on the rectifier (EZ81), slight asymmetry between the +ve and -ve 'Y' amp input stages (ECF80s) in terms of the anode and grid biasing arrangements and the input attenuator is 'missing' the probe matching trimmer caps.

I just won an equally beat-up S31 which I'm collecting on Friday so I'll do a compare and contrast when I get it home. I also got a TQ 'C1' Scope Calibrator a few weeks back - Serial number 3 - so an early model as well!? I've got that working nicely too, in fact you can just see part of it's chassis, the covers are going out for painting, in the picture of the scope which is displaying it's output.

As far as the Tek involvement goes, the article in TekTalk announcing the addition of Telequipment to Tektronix is dated Spring 1967 so about then I guess?

True double beam? Yes, when I made the move to Electronics Technician at the Cavendish labs in the late '60s one of the first things I was handed was a heap of dead or dying? D43s - they had dozens and dozens of them in the teaching and research labs - to repair/recalibrate. A very nice instrument for the money but fried themselves all the time. Convection cooling is nice and quiet but sadly just not adequate for continuous use!

I hope we can find out more early history, I wonder if there are any ex Telequipment folk out there because it would be great to get it written down.

All the best,
Adrian


On 4/3/2018 7:28 PM, Leslie Austin wrote:

That is an interesting scope you have there Adrian. I have seen or owned many S31 scopes, but that one is different to anything I have seen. There seem to be many differences, but without doubt it is either a prototype or an early model unknown to me. Every one I have seen had a serial number on the back, does this? Every S31 (and S32, S32A, D32, S/D33, S/D43, D*53*) I have seen had two covers, inverted L shape, with two screws retaining handle and sides. I have never seen WHITE OEM knobs!

I had a rather special device, obviously based on the S31, but it was a TV monochrome CRT tester. The rear panel had been "turned around" so that the S31 ID info was on the inside. Different transformer clearly different circuit, and all valves had been removed. I decided it was a project to be "analysed", and I used to bring it out on Christmas day to kill time, but as so often happens, it never got finalised. I offered it FOC on a UK forum, got an assurance it would be "completed", but 12months later found it had? had the CRT removed and the rest scrapped. Hmm!

But back to TQ generally. I don't know when the takeover took place, but by 1968, Tek were certainly getting involved. I have here a conversion list of TQ part numbers, for example, the mains transformer for the S31 had been part number T1, but now became 150-0071-00, which is clearly a Tek part number. The list is dated May 1968.

It is interesting to look at the front of TQ scopes. Early models clearly fitted with UK sourced knobs; Mostly black with some red "outers" with stacked controls. Common from S31 thro to the DM53A, but from the DM64 (terrible 'scope, TEK CRT), D*63, D65/66/67, D75, D83 they all had US sourced TEK knobs, and knob prices shot up!

There is a 1973 US version catalogue of Telequipment scopes available online, the knob styles can be clearly seen there.

Every TQ scope from S31 had TRIGGERED sweep, until then all cheaper UK scopes were non-triggered. That is what made them so useful for any decent TV repair shop, and affordable.

TQ also produced suitably modified scopes for the US firm Perkin-Elmer. A variation of the S51 was produced as a heart monitor. I think I still have a bare board for one, and some circuitry for it.

C.M. Jones referred to his D31, with true dual gun/beam tube. Quite a few of the early "D" scopes had dual guns, most with single timebase but dual Y-amps. There were however the D55, D55A and D56 which had true dual guns, dual Y amps, AND dual timebases!

Earlier I referred to the DM64, with its lousy TEK bistable CRT. However TQ produced the D53S, DM53A and the DM63. These were REAL storage scopes with variable persistence, all using GEC storage tubes. They were quality, and on a DM53A I could store a trace, switch off the scope, and switch back on a couple of MONTHS later, with the trace still stored!

I used to buy, service, calibrate and sell scopes from 1979 for about 10 years. I quickly learned that anything with valves, other than TQ or TEK were best left to others, stuff like Hartley, and Advance reminded me of some Pye Colour TVs, terrible.

I still have a few service docs on the late '60s and 70s TQ scopes, and if an S31 landed in front of me now, I would enjoy servicing and calibrating it.

Les.


On 03/04/18 14:34, Adrian wrote:

So once upon a time, in Olde Merrie England, there was a company that produced cheap but adequate oscilloscopes which they sold around the world. Then, one day they decided to remodel them to make them more appealing to their cousins in a land far away across the sea. This must have worked because a few years later one of their cousins, a Mr Tek Tronix, sailed all the way across the sea to England and bought the entire company!

Ahem, sorry!...... Meanwhile, back at the point.... I acquired a basket case of an early (pre '58 facelift) Serviscope which may be either an early S31 or a forerunner of it. This example had obviously done service as a parts mule prior to being stored carefully for a decade or two in the corner of a particularly wet and muddy field. After spending way more hours and money than it will ever be worth in a million years it is pretty much up and running and, as it is devoid of its case, I would like to find a picture so I can re-make a reasonable facsimile of it.

In more detail, the thing is very close in both appearance and schematic to an S31. It is constructed in a point-to-point way with tag-strip and not a PCB in sight. The front panel is finished in silver (was once anyway!) hammer finish paint with white legends and black & white knobs. From the looks of it the case must have been a 5-sided box a la the S51 and was retained by two 1/4 turn fasteners on the rear panel.

Some pix here: /g/TekScopes/album?id=42175 Please ignore the tacked-on components, they were just to get it going and will be replaced with more authentic looking parts shortly. The chassis mounted caps and selenium rectifiers have been hollowed out and re-filled already!

From my use of google at least, information on Telequipment Ltd and

its products prior to the product facelift and subsequent takeover seems scarce, most of the very little I know has been thanks to the VintageTek museum page and a link to the spring '67 article in TekTalk about the acquisition. Bob Haas and Dave Brown at VintageTek have been really helpful and burrowed around their archives but not found anything. I was wondering if anyone in this group may know, or could point me at, people who could help fill in the gap. Apart from anything else Telequipment is a bit of UK industrial history that should not be lost?

...and if you have been, thanks for reading!
Best,
Adrian