Telequipment calibration equipment.

[MotorBikeLes]

Telequipment Calibration equipment

Like all the oscilloscope manufacturers of yesteryear, Telequipment supplied full recalibration instructions.
The earliest models (eg S31 Serviscope) made no comment on the equipment to be used. The only reference to an item NOT part of the basic unit is use of a probe for attenuator adjustment. Whilst not stated, this would be a 2:1 “normaliser”, but such were not supplied. The obvious calibrator to use would be their C1, later C1A.
By the time of the D67A models, a calibrator and sine wave generator are mentioned, but no model specified.
The D75 and D83 models are a little more explicit. Requiring the V.Cal unit 067-0672-00, the H.Cal unit, 067-0673-00 as well as extension lead, 195-0112-00.
A Y-amp extension board, 670-2864-00 is also required together with the usual normalisers, monitor ‘scope and sundry other items. When we come to vertical amp pulse response, a 1MHz pulse with better than 1ns risetime is specified. This was beyond capability of the C1 (5ns) but was OK with the C3. Presumably the C3 was the default calibrator, also handling timing, amplifiers and a TV output for that TV triggering section. Again no mention of which signal generator to use, but as TQ had been part of Tektronix from 1966, it is likely the Tek 191 would be the default unit.

Whilst most of the above units are covered by manufacturer’s documentation, nothing is known to have been published on the H-cal unit for D75/D83, or the V-Cal unit for D(M)63, D75/D83. These are now covered in the following documentation. NONE of it is official Telequipment or Tektronix documentation.
Finally there is a short item on the D(M)63 dummy Y-amp plug-ins, with a simple challenge for the reader.

First some notes on my own two cal units.
My V-cal is either very early production or a prototype, as unlike one recently shown on TEKWIKI, it has no circuit info silk screened on the PCB. Some components are different, for example two 330 ohm resistors in parallel instead of the single 165 ohm shown on Tekwiki.
It has an earlier equipment number than any others so far known to me.
My H-cal is almost certainly a prototype. Its components have been “fitted on to” a totally incorrect PCB. This is marked PC130, rather than PC155. It appears to be a Y-preamp board for a low frequency differential unit, possibly the one fitted to the V3 plug-in for these oscilloscopes. (It looks like junction transistors not dual FET front end, with two channels hence possible conclusion as to its source). The ID is simply a paper label marked TG1172, suggesting it was assembled by TG in Nov. 1972.
I believe both of my units came from the Telequipment plant at Southgate.

[Alistair D]

Thanks for that Les.

PC130 is the main amplifier board used in the V2 Y amplifier module. I have attached a picture of the board as fitted to my own V2.

The similarities between the PC130 and the PC152 as used in the V4 are striking. Comparing the 2 boards, component positioning, numbering and values are the same. The areas where they are different are that while PC152 uses dual semiconductors in some positions, PC130 is all individual devices. PC152 has a few extra components to facilitate the X5 gain function.

I am in the process of producing a document which in conjunction with a V4 manual will allow repair and calibration of the V2. When(if) I get round to completing it I will post a copy.

Sorry for all the waffle. It would be interesting to know if your unprinted PC130 is the same board as mine.

Al

[MotorBikeLes]

Al, so a V2. I had realised it was NOT V4 (have a pdf manual after all), and I see some close PC numbers in D75. I had even wondered if it could be for the TV1 unit. My PC 130 looks identical to yours, except for the cutout in the position for an H panel, and there IS NO slot on the correct side for V2. Fully silk screened, but of course wholly inappropriate for a H-Cal board, but that is what was used.
My V-cal board is the same as the one on Tekwiki, but simply not silk screened other than that of the PC number.
There is no mention of the V2 in the 1973 US catalogue, or the 1977 UK one.
I MAY have had a manual once, as I thought I had almost every one, but that was 35 years ago.
Les.

[Pinörkel]

@MotorBikeLes: Thank you for your work.

On my 067-0673-00 H-unit(like shown in the TEKWIKI), the transistor is labeled TR1050 and it is a BC109C. In addition to that, mine has a 47 Ohms resistor in series with the BNC socket center pin. I did not have time to check the V-unit for differences yet. When I'm done comparing your circuit diagrams with my units, maybe I complete my already started circuit diagrams using your versions and create a set of TQ-style circuit diagrams out of it.

[Pinörkel]

Just checked the transistors on my V-unit. The TR1001 is a Tek 151-1036-00 dual FET like in the input stages of the V4. TR1002 and TR1003 on my unit are 2N2369 NPN bipolar transistors. As opposed to your unit, C1002 on my unit is the same 10nF capacitor as C1001, C1005 and C1006.

Seeing your parts lists, I wonder how you managed to determine all the TEK part numbers and the specs of the two variable capacitors C1003 and C1004. Mine are not labeled at all, so the only way would be to desolder them and measure them by turning, which would void any potential calibration.

[MotorBikeLes]

Hi, now you have made me think. I will have to check if mine has that 47R. I remember seeing one, but maybe only in the Tekwiki photo.
I have various TQ docs where they regard BC546, BSX20, 2N2369 (plus others) as interchangeable. At this time, and a little earlier, there was a shortage of semicons generally, so alternatives were frequently offered.
I remember on the CTV front, Ferguson used to list generic numbers for semicons used and supplied by them. They could be a wide range of suitable alternatives under a simple reference number.
Your dual FET. 151-1036-00 was a commonly used one by TQ at that time, for example in the V3, probably the V4 and others. No equivalents to my knowledge, but must be similar to the TF1551 in both mine and Mark's (if I recall). I have tested the 1036 in the past, so have enough info to be able to sort possible replacements. Well, equivalent on the curve tracer, but no comment on HF response.
Regarding part numbers, I looked at "similar" TQ stuff of same vintage for like parts, but covered myself with the E&O Exc. note.
One other thing, my units always had covers on from when I got them. Since we know of no official documentation, then "who knows".
I looked in a D63 manual today, and there was no reference whatsoever to the "Dummy" units.
You may notice that the dummy unit has no connection to the unblank contact. As Mark pointed out, and I confirmed today, that connection 3 is linked direct to 0V on the mother board. Not the case with D75 or D83.
I notice nobody has taken up my challenge to do something about a possible "component tester" circuit for any of these mainframes.
I think any further ref to these three modules should now be on the separate TQ Cal thread.
Les.

[Chris55000]

Hi!

A component tester would need an output to both the Vertical Amplifier and also the Horizontal Amplifier – are both of these accessible on SK602?

Basically all this would be is the low voltage "octopus" type circuit fed to the Vertical & Amplifier circuits, with V & H preamplifiers fed from the +105V h.t. line!

Be that as it may, I'd like to take up this challenge and I'll post my circuit in a few days after I've drawn it!

Chris Williams

[MotorBikeLes]

Chris, does it need to output to the H amp, if instead it can input from same?
Both D(M)63s have a front panel sawtooth out. Only 10v a?c manual, but it could be "multiplied if needed from the +105v line
The S2A module of D75/83 also have the sawtooth out.
Glad somebody is accepting the challenge. My circuit design skills (and often understanding too) are very limited.

[MotorBikeLes]

Thanks to input from Dennis (Pinorkel), as well as that from Mark earlier, some silly errors have been identified in my original circuits.
My H Cal module does not have the extra 47R that is mentioned above, but since mine is so very obvious pre-production, I have added it in the circuit. I may possibly change it on my unit, but not now.
Les.
I have shown C02 on the +24v line. Correct, but it should be adjacent to the dual FET

[Chris55000]

Hi!

Yes, the normal type of X/Y "octopus" style component tester does require a connection to the horizontal amplifier as these show applied voltage horizontally and current vertically!

I'll study the D63 manual and see if SK602 has a feed to the horizontal amplifier, either directly or indirectly by switching!

Since there was an "H Cal" unit produced, it's obvious that one of the plugin socket connectors has to have access to the X plates!

I'll study the D63 bookwork and get to work on it!

I may have to buy a D63/DM63 to design this project, so if any Member can furnish me with a D63/DM63 @ a reasonable price (I'm ok up £100 next payday!) please PM me!

Chris Williams

[MotorBikeLes]

Chris, not that simple. The two cal modules have different PCBs, with the location index in different places. The connections at the sockets on the mainframe are specific. The D75 and D83 have one vertical plug in amplifier (typically a V4), and one plug in sweep unit (typically an S2A). The D63/DM63 scopes have a built in timebase, with two bays for Y amps of same type as D75/D83.
D75/D83 have single gun tubes with single or dual trace according to the Y plug in.
The D63/DM63 has a single gun, split beam tube, enabling it to display one, two, three or four traces dependant on the Y plug ins fitted.
If you want to use the sawtooth out, you would pick it up from the socket on the front of the timebase, and fit either a trailing lead or similar socket on the front of the dummy.
The D75 and D83 only use the H Cal module, all four types require the V Cal module during recalibration.
I hope that clarifies things.
I do have at least on 63 series scope which I could sell, but Isle of Man may not be convenient.
Les.

[Chris55000]

Hi!

Afternoon Les!

Ed Dinning's offered me an assortment of bits, including a DM64, so I've taken up his offer on those (for postage costs), but these won't be ready till after he gets back, but I definitely think a Component Tester or Curve Tracer plugin is definitely worth looking into, as prices for both V/I testers and Curve Tracer units, (Chinese Toys excepted!) have been run up by the "valve foolery" and "semiconductor foolery" brigades to absolutely astronomical levels, so even if some wiring/component changes need to be done on the mainframes, the costs would be nothing like what Tek 576 prices have run up to!

Can you find out how much it'd would cost for your DM63 (your price + postage from I.O.M. inclusive please?) for me & PM me please Les? I'm after one anyway for another project as well!

Chris Williams

[mhennessy]

If we stay with Les's thought - a Hameg-style component tester - then yes, this is quite feasible.

There are 2 problems:

1. No 50Hz AC comes into the Y plugins
2. No obvious way to get a signal to the X amplifier

To solve the first, you could make use of pin 11, and pick up a feed of the 6.3V AC that feeds the timebase module. However, I really don't like the idea of that, so would much prefer to build an oscillator and power amplifier into the space of the plugin. Doing that actually makes the I-sensing easier.

Solving the second problem is easy: simply mount a BNC socket on the front panel of the plugin, then use a short BNC-BNC cable to link it across to the X input on the timebase.

So, pretty straightforward, and no mods needed to the mainframe or timebase module, so the 'scope retains full functionality.

However...

Chris appears to have morphed this idea into a fully-blown curve tracer. This is not so practical, unfortunately.

For a curve tracer to be "useful" - quotes because they rarely are in reality - you need serious amounts of power reserves to apply to the poor DUT. I forget the figures for the Tek 576 that I gave away to a forum member some years back, but suffice to say, that accounted for most of the weight. There simply isn't the reserve available from the transformer in the DM63, and nor is there the space to install another transformer for the task.

We have a Telequipment CT71 at work. I can't honestly tell you the last time anyone used it. But I see Hameg owners use the component tester facility all the time.

BTW, CT71s don't fetch huge amounts. The last one I saw sell was about £40 posted. Certainly not "astronomical". I'd take one over a Tek 576 because I can actually lift it and it would fit on the bench. But in practice, when we do decide to throw our CT71 away, I'll almost certainly give it away via the forum rather than add it to my collection.

[MotorBikeLes]

well, I can see something may happen with component testing after all, but I am just a bystander.
Very fair point about curve tracer. I bought a CT71 about 40 years ago from a former TQ high up. (purely coincidence, nothing to do with my former workshop contact). A later sold it (financial necessity). I then acquired a TEK CT, the solid state one not the original valve jobbie. An amazing deal from a guy who bought it as his company was closing down his section. Later sold that for the same reason, after adding a few bargain extras to it. Then, 20 years ago I bagged another CT71 which I still have. Used to use it a lot on FETs, it diagnosed a very tricky problem for me once. More recently I used it with a 6.3v heater transformer for curve tracing ECC8x valves.
But to Marks point, TWO quite heavy transformers, the main one is bigger than the Y-plug in. (Wrong shape, but bigger on some dimensions.
Chris, the DM64 is a sub 10MHz "bistable" tubed storage scope. Not much use, unless you are very lucky, or you just want it for the box and transformer. It uses a TEK tube, a bit like the old Tek564, whereas the DM63 uses a superb GEC tube.
TQ used an earlier GEC tube in their D53S and DM53A scopes. (Not very big, but HEAVY!!!) I have stored a trace on one, switched it off, and one month later the trace was there after switch on!
I will look at my 63 later or tomorrow. Not sure if conventional or storage.
Les.

[Pinörkel]

I just finished a set of TQ-style circuit diagrams for the calibration units. It took quite a while to imitate the visual style of the TQ diagrams from that time, but it turned out quite well. I find it quite intriguing that the old TQ circuit diagrams were apparently all type-set by hand. The circuit design of the V-unit is based on that of the input stage of the V4 amplifier. The diagrams by Les helped me a lot with error checking and he also found a typo in my files. Thanks for that.
067-0672-00
067-0673-00
Once I am sure the diagrams do not contain any major errors, I will release them to the public as vector files.

[Chris55000]

Hi!

For a curve tracer to be "useful" - quotes because they rarely are in reality - you need serious amounts of power reserves to apply to the poor DUT. I forget the figures for the Tek 576 that I gave away to a forum member some years back, but suffice to say, that accounted for most of the weight. There simply isn't the reserve available from the transformer in the DM63, and nor is there the space to install another transformer for the task.

This I am aware of but I have details of a quite respectable design in mind that requires only two small transformers (the maximum collector current limitation is 500mA) but provides up to 140V test voltage, suitable for the low power high voltage transistors used on this forum and to a lesser extent with medium power low voltage devices, and the prototype was built in only a small plastic case, so I'm fairly sure it could be assembled on a TQ plugin chassis!

Chris

[Chris55000]

Hi!

Originally Posted by mhennessy

If we stay with Les's thought - a Hameg-style component tester - then yes, this is quite feasible.

There are 2 problems:

1. No 50Hz AC comes into the Y plugins
2. No obvious way to get a signal to the X amplifier

To solve the first, you could make use of pin 11, and pick up a feed of the 6.3V AC that feeds the timebase module. However, I really don't like the idea of that, so would much prefer to build an oscillator and power amplifier into the space of the plugin. Doing that actually makes the I-sensing easier.

Solving the second problem is easy: simply mount a BNC socket on the front panel of the plugin, then use a short BNC-BNC cable to link it across to the X input on the timebase.

So, pretty straightforward, and no mods needed to the mainframe or timebase module, so the 'scope retains full functionality.

I recently bought one of the Chinese clones of the Tek TR210/Huntron 2000 and that could well be built into a TQ plugin chassis, but I suspect the micro in the Chinese unit I bought is certainly code–protected, but Huntron also made a version where the selection functions are carried out in ordinary CMOS logic, which can certainly be copied!

Huntron's are another item suffering from the scourge of "foolery" prices as well, and I'm afraid to say CT71s are as well – the last one for sale I saw was over £600!

Chris Williams

[MotorBikeLes]

Chris wrote Huntron's are another item suffering from the scourge of "foolery" prices as well, and I'm afraid to say CT71s are as well – the last one for sale I saw was over £600!
WOW! For that you can have my CT71 and say half a dozen scopes as well, + spares etc.
Roll up, Roll up!
Les.

[mhennessy]

The one I mentioned that sold for around £40 (including postage) can still be found if you search for "sold items" on that well known marketplace. While I don't follow these closely, I don't think I've ever seen one sell for more that £100. If we assume the £600 was the price it actually sold for, rather than an "optimistic" asking price, then I guess sellers sometimes get lucky! Definitely an "outlier" IMHO.

[loulou31]

Some weeks ago I found a CT-71 at 200£, on well known market place. For my opinion is a honest price. This a low end curve tracer from Tektronix ( Telequipment) but with enough features : max 1000V and 2A at low low voltage / max 10W and good vertical sensitivity ( 5na/div) for me. The only issue I have seen is that the base current generator is not a constant current generator but a voltage generator in series with a resistor : the first step is quite false and require to use the offset adjustment, mainly if you test a Darlington.
Yes, usually prices are quite high for curve tracers mainly on Tek 576 or 577 (800 to 1000€ for a working unit) , because there is no such product new for amateur market as it is the case for oscilloscope, function generator....The performances of adaptors we can find to connect to an oscilloscope are quite limited in term of voltage and low current.

Jean-Louis