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Old 22nd Jun 2018, 3:22 pm   #1
Diabolical Artificer
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Default Telequipment D/S52

Got one of these on the bench. I have a dot on the CRT, but it's not split into two traces. Reading the manual it says it has a "splitter plate", so how does this work? As there is no "alt/chop" I presume it somehow splits the beam using a DC voltage, or does it?

I'm not sure where the splitter plate is. Tried to pull a datasheet for the CRT but it could be anyone of several CRT's. Could the splitter be A2 pin 8 10 (8)?

To make things more interesting the scope says S52 on the front, but it has a round CRT, I've read that the S52 has a square one. this means it's a D52. EHT is one Senticil K8/50 and one 0.05u cap, so presume EHT is around 1kv +. Havn't measured it as I have a "trace"

Apart from no split trace, the TB isn't running and I have a few voltages that are off spec, nothing major.

Andy.
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Old 22nd Jun 2018, 4:13 pm   #2
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Default Re: Telequipment D/S52

I think the manual means that you have one cathode/grid structure which, together with the 'spliter plate' gives 2 electron beams. Rather than having 2 separate electron guns as in. say, the Tektronix 555. Is there only one intensity and one focus control that covers both beams?

Is it possible you have 2 beams but one is deflected off-screen? Check the voltages on each pair of Y plates, are the 2 plates of a pair at similar voltages? Try shorting the 2 plates of a pair together briefly (take care, expect around 300V wrt the chassis on them) and see what the dot does.
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Old 22nd Jun 2018, 5:46 pm   #3
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Default Re: Telequipment D/S52

Do you have one or two 'Y' amplifiers? The S52 has only one.

Ron
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Old 22nd Jun 2018, 6:46 pm   #4
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Default Re: Telequipment D/S52

I’ll follow this thread Andy, it will be informative.
Just missed scope on the offered section, gone within seven minutes!
Cheers
John
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Old 22nd Jun 2018, 8:30 pm   #5
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Default Re: Telequipment D/S52

Perhaps you would post a picture of the front panel. That would clarify whether a S52 or a D52.
The S52 is single beam, with the round screen Brimar D13-30 tube, giving a 10 x 10 cm display area, and one Y amplifier .
The D52 is a double beam, with a rectangular screen Etel E13-12, or equivalents GEC 1324S, Philips contract 55451, Etel prototype CR171.

The beam is generated from a single cathode/grid/focus assembly, and then split by a divider plate with two holes into two beams. The beam is split at the anode a3 (pins 8 and 10, which should be connected together), after the focus anode a2 (pin5). First anode a1 is pins 6 &9.
Unlike the earlier split beam tubes, which had a single deflection plate on each channel, and so inverted one trace Cossor 09D.

Single focus and brilliance controls. The brightness of the two beams is equalised by a small magnet near the cathode/grid asembly at the base.
If you have the dual beam version, measure the voltages on the deflection plates, and work back to the Y Amplifiers, as Tony Duel suggests.

I assume you have the manual. The tube data sheet does not tell you much more than the manual.
If you are wondering about the beam splitting, read the verbose description for the 09D tube in the Cossor manual for the 339 oscilloscope. They were very proud of inventing it, in about 1936.
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Old 22nd Jun 2018, 8:53 pm   #6
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Default Re: Telequipment D/S52

I thought they were both round screen CRT's?

Lawrence.
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Old 22nd Jun 2018, 9:31 pm   #7
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Default Re: Telequipment D/S52

"Is it possible you have 2 beams but one is deflected off-screen?" Possible, though the dot is rather big @ about 3/8" 8mm dia. Am unable to decrease size using the focus/brilliance controls. I have no Y movement using the up/down pots also.

It has two Y amps, a round 12 pin CRT, with a single side connection. One brilliance/focus.

"I’ll follow this thread Andy, it will be informative." You'd learn a lot having a go at fixing it yourself John, if you had it off me. it would stand you in good stead if it needs servicing in the future. I've worked on a few of these Tele scopes and with the excellent help I've had, I've been able mostly to fix them, so am sure you'd be ok. am cool whichever,

Thanks Bill, that's great as always.

"I thought they were both round screen CRT's?" This one is round, see pic, apologies for quality, light not great.

Andy.
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Old 22nd Jun 2018, 9:41 pm   #8
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Default Re: Telequipment D/S52

Quote:
Originally Posted by Diabolical Artificer View Post
To make things more interesting the scope says S52 on the front, but it has a round CRT, I've read that the S52 has a square one. this means it's a D52.
The D52 pics I've seen show circular CRT, here's a circular 55451, scroll down to near the end:

http://www.sphere.bc.ca/test/crts.html

The S52 is also circular as you know.

If there was a rectangular screen for either it would say so in the blurb but there is no mention in the catalogue, just says flat 5" CRT:

https://archive.org/stream/bitsavers...ge/n7/mode/2up

Unless there was two versions.

Lawrence.

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Old 22nd Jun 2018, 10:53 pm   #9
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Default Re: Telequipment D/S52

Hi Andy
I don’t want to put you to any trouble or waste your time, but I would prefer to have a working scope.
Cheers
John
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Old 22nd Jun 2018, 11:23 pm   #10
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Default Re: Telequipment D/S52

The attachments to post #7 show a single beam S52 scope with matched vertical and horizontal amplifiers. There is, therefore, only one vertical amplifier.

Alan
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Old 23rd Jun 2018, 7:17 am   #11
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Default Re: Telequipment D/S52

Thanks Lawrence, it looks like the one in your second link, which points to a S52.

I'd blanked out the "horizontal amplifier" bit Alan, just presumed it was two vert amps. So why the dicken's would you need a horizontal amplifier? XY mode which means it would make a good curve tracer.

So this is an S52 I've been chasing a red herring, sorry about that. On with sorting out the TB in that case.

Cheers, A.
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Old 23rd Jun 2018, 8:02 am   #12
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Default Re: Telequipment D/S52

Andy I have sent you a pm.
I have been offered a Isotech working scope, which I have accepted.
Once again thank you for time.
Cheers
John
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Old 23rd Jun 2018, 10:23 am   #13
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Default Re: Telequipment D/S52

Quote:
Originally Posted by Diabolical Artificer View Post
Thanks Lawrence, it looks like the one in your second link, which points to a S52.

I'd blanked out the "horizontal amplifier" bit Alan, just presumed it was two vert amps. So why the dicken's would you need a horizontal amplifier? XY mode which means it would make a good curve tracer.

So this is an S52 I've been chasing a red herring, sorry about that. On with sorting out the TB in that case.

Cheers, A.
Phase measurement.

Quick introduction video here:

https://www.youtube.com/watch?v=t6nGiBzGLD8

Lawrence.

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Old 23rd Jun 2018, 12:11 pm   #14
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Default Re: Telequipment D/S52

Both the S52 and D52 have round CRT's, but the plastic escutcheon makes them look square-ish.

As far as I am aware the D52 can have 2 CRT variants with different bases (otherwise compatible) and when the D52 came out it was available with either a green P31 style phosphor, or a short blue/long yellow phosphor (similar to the P7 type). This version came with an amber filter over the CRT and was sometimes used in slow event recording or medical applications. The D52 also has an interesting vertical gain circuit with transistors to boost the gain x10 in the valve based vertical amplifiers, so its a bit of a hybrid.

I assume the S52 (as shown in the photo post 7), probably had similar CRT variants too. But of course as noted the D52 has the single gun split beam type and the two vertical amplifiers.

My D52 had "self cracking resistors" as explained in the latter half of this article. If you see any of these in your S52, replace them, there may be none, but its worth checking especially if there are multiple faults:

http://worldphaco.com/uploads/ELECTR...AIN_FRAMES.pdf

The selenium pile stick EHT rectifiers in these scopes are notorious for failure, as are the EHT filter caps too.
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Old 23rd Jun 2018, 7:44 pm   #15
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Default Re: Telequipment D/S52

Well, that one is a bit different. I have had a few of each S and D 52s thro' my hands, but not seen that one before. I used to have (I thought) all the TQ manuals, but I never had that one. Maybe a prototype? I once had a D67 which was a prototype, and never had a manual for that. It would appear to be an S52 in a D52 casing, with the second vertical amp replaced by something similar, but as a post "timed output" fed in for further conditioning. Most scopes have an XY facility, but the gain and bandwidth of the X beam is severely reduced compared with the Y amp. It would be interesting to do a bandwidth check on the X channel compared with whatever is quoted for a stock S52. I will have another look through all my old service sheets to see if anything exists. TQ used to do variants of stock designs for odd markets. They did one branded "Perkin Elmer" for that US company. It was an S51, but modified with a slow persistence tube for heart monitor work. I used to have a board for one of those, may still have it.
A rare one Andy. Use the circuit of the S51, but draw one out for the X-amp. Should not be too difficult.
Les.
ps, I think I have a good D52 mains trannie here somewhere, if anybody should be in need of one.

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Old 24th Jun 2018, 12:09 am   #16
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Default Re: Telequipment D/S52

Andy's attachment to post #1 looks like an extract from the D52/S52 manual published in October 1969 in which case I would assume he has a pdf copy of the full manual. This has the schematic for the S52's vertical and horizontal input amplifiers plus all the other circuit diagrams, including the one for the S52's CRT.

I doubt if Telequipment sold many S52s as it was expensive in terms of single beam scopes of the day but it was included in the 1968 and 1969 US catalogues.

Alan
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Old 24th Jun 2018, 7:48 am   #17
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Default Re: Telequipment D/S52

Stripped it down yesterday to get at the PSU/TB board. The CRT is a D13-30GH. I found a cracked XY amp PCB. It looks like the scope had been bungy jumping at some point in the past, but luckily these scopes are built like a brick uknowhat. Have repaired the PCB and straightened the dink on the front.

Trace now moving, but have no flyback and now have a fault on the vertical amp with uneven voltages on the deflector plates, so trace vanishes.

I found the cause of the TB fault; V104 was an ECF80 when it should be a ECC88, as a result a resistor was smoking, so I thought the selenium rectifier was dead, it isn't and have left it and the EHT cap in situ.

The only other faults I've found are a duff germanium diode - MR303, so the trigger waveform wasn't getting to V104 and as on the D43 I worked on, swopping valves out fixed most faults. I'm going to have a test session today and test a big batch of ECC88's and ECF80's.

Thanks for the heads up on the cracking R's Argus.

It is unusual Les, I made the mistake of assuming it was a normal scope, and we know what assuming does.... I also sat and read some of the manual instead of just looking at the pictures : )

Manual I have is the one below (1969) as well as a printed copy of the S51. The PSU and TB are essentially the same as all these Tele scopes, EG S51, D43 etc but the vet/horiz amps have tranny's in em, see attached.

Thanks for all your input. Andy.
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Old 24th Jun 2018, 1:48 pm   #18
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Default Re: Telequipment D/S52

Telequipment S52.
Thanks to Argus25 for tip about cracking resistors. Lawrence MS660 is quite right. The E13-12 / 1324S is a circular split beam tube, not square as I said.

This S52 is an extraordinary scope. It is described as with matched X and Y amplifiers. It has two identical Amplifiers (interesting hybrids with valves and transistors), bandwidth 3Mhz. At first glance it looks like a dual beam scope, but then you see that the amplifiers are labelled Vertical and Horizontal, but otherwise identical.

It also has a separate Timebase and X amplifer, very similar indeed to that in the D43 and others.
There is a switch to change between X-Y or Timebase operation.

The 1971 prices were £130 for the D52 and £140 for the S52.

The tube is unique Brimar tube D13-30 intended for X-Y operations, with identical deflection sensitivity in both directions of 17 v/cm.
The tube used in the Telequipment CT71 Curve Tracer is clearly a developed version - D16-100, square face, also 10x10 cm, slightly shorter with same sensitivity.

The D52 with the split beam tube has two of the same amplifiers for the Y trace, but with lower anode loads and the same Timebase and X amplifier.

The E13-12 is 17 v/cm deflection sensitivity for X direction, but better than the D13-30 tube at 11v/cm for the Y direction, allowing the reduced anode loads and so greater bandwidth of 6Mhz.
You seem to have all the data and manuals.
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Old 24th Jun 2018, 4:39 pm   #19
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Default Re: Telequipment D/S52

Thanks again Bill. "There is a switch to change between X-Y or Timebase operation." Where Couldn't find it the other day, just found it hiding on the back...doh! Maybe this is why the sweep isn't working. Spent the morning trying to figure out why there is no ramp.

So anyway, got fed up with that and went tested a bucket load of valves, all pulls ..... which was interesting. Out of over 30 ECC88's I got 6 good un's. Six! Managed to get another four that will do, just about. That's a 2:1 failure rate, I was very surprised.

Out of 12 E88CC's they all failed, the best i got was one with a Ia of 2.2/3.5mA tested at 225v HT, -7v bias, Ia should be around 5mA.

Out of 14 ECF80's I got 3 good, usable valves, which means I'm going to struggle getting both the D43 and S52 running.

What really surprised me was how many had failed heaters, I had to jiggle about 20 valves and then quickly zap them with 12.6v to get the heaters to light, I "resurrected" about 5 doing this. I've tested about 100 ECC81/2/3's and had no failed htr's or shorts.

What was also interesting is that "Teonix" brand were all c**p as were 3 Siemens CCa's (special E88CC's?) Also of note was the amount of Mullard 6DJ8's with iffy's htr's.

So I can only assume that life for a valve in a scope is hard.

Back on the scope tomorrow, Andy.
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Old 24th Jun 2018, 5:40 pm   #20
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Default Re: Telequipment D/S52

Don't forget that both switches have to be closed and making contact with continuity to chassis for the time base to work (the two in series in V104's cathode circuit)

Lawrence.

Last edited by ms660; 24th Jun 2018 at 5:47 pm.
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