Help please - What is this contraption??

[Jellybean]

Hi everyone,

Newbie here, please be nice

I'm clearing out my Dad's workshop and happened upon this item. I have been searching online and think it is a "Solartron CD1400 Oscilloscope" from 1969. I don't want to keep it but have no idea what to do with it, or how much it's worth (if anything), being a specialised item. There's one on eBay for £10 and one for £200, so I'm a bit confused as to its value. I would like it to go somewhere useful, though (is it too young to be donated to a specialised museum, for example?).

Can anyone help shed some light on what this contraption is and what I should do with it?!

Thank you

[Sinewave]

Well it certainly is a 'scope.

Working order and condition of functions are generally what dictates the price. Including desirability.

[Jellybean]

Thanks Sinewave. I plug it in and a green light appears on the screen. Seems to move around, depending on where the X and Y knobs are turned to. I wouldn't know if it worked beyond that though, I don't even know what it's for or how to use it!

[paulsherwin]

I would say that £10 is nearer to the mark than £200. It won't attract a lot of interest as a vintage item, but it lacks the performance and facilities of more modern instruments. It would be a decent first scope for someone interested in fixing old radios though, if the size and weight aren't a problem.

https://en.wikipedia.org/wiki/Oscilloscope

[Bazz4CQJ]

It's described quite well here https://www.thevalvepage.com/testeq/...400/cd1400.htm.

15MHz, dual channel, I'd guess that quite a lot of people would be very happy to own it, but seems that it is in the £10-20 price range.

B

[paulsherwin]

It would have been a professional piece of test equipment in 1969, and not cheap. Quite late for an all valve scope.

[Radio Wrangler]

In its day it was pretty much at the top end of british made oscilloscopes, but not a patch on the American Tektronix ones of the same era.

All valve. Transistors of that era couldn't handle the voltages needed to drive the cathode ray tube.

As said earlier, it's good for its era, but it was soon overtaken by higher performance and lower maintenance instruments.

£10 to £20 seems fair.

THere's actually quite a number of these kicking around. Common in university labs of the time. So if anyone fancied using a Solartron 1400, there are plenty around cheap enough to use for spares.

It's a late enough scope to be operated easily by anyone who learned on more modern instruments. Earlier scopes than the 1400 were difficult to get properly scaled pictures on, you could see the shapes of waves, but it was a lot of effort to measure things.

The moving light on the screen bit sounds quite promising. It suggests that various systems inside it are showing signs of life. It might even be a go-er.

David

[TonyDuell]

It is indeed a Solartron CD1400. I have one (it was my first oscilloscope). You have 2 of the 'normal' Y amplfiier modules on the left (15MHz bandwidth) and the standard timebase on the right. These modules could be replaced by others for special applications but the ones you have are the normal ones, useful for most jobs.

A bit of background. The name 'oscilloscope' essentially means in instrument for looking at (the 'scope' part) oscillations. In this case oscillations of an electrical voltage. It displays a graph on the screen of voltage (vertically) against time (horizontally). The cathode ray tube displays a small dot on the screen (DO NOT display a bright dot on the screen, you can ruin the tube if you do), it is moved vertically by the voltage applied to the input socket and moved horizontally at a constant rate from left to right by the timebase. Controls on the Y amplifier (Y= vertical as you might expext) let you set it for measuring different voltages. Controls on the timebase control how fast the spot moves across the screen so you can look at oscillations of different frequencies.

Actually that is a simpification in this case. The CRT displays 2 dots at the same time. They move across the screen together at the same rate controlled by the timebase. But they are moved up and down separately by the 2 inputs and the 2 Y amplifiers. You can therefore compare 2 signals -- perhaps the input and output of an amplifier.

It is still a useable instrument, but there are better ones available now (higher bandwidth meaning you can look at higher frequency signals and 'storage' meaning the graph remains on the screen until you clear it, so you can look at events that happen once, for example). That said, I do still use mine.

[kalee20]

I must say I'd give £10 for it as a punt (based on the fact that it shows signs of life). I'd even go to £50! But no more.

[buggies]

I had to skip quite a few of those when my storage space became unavailable.
The mains transformers tended to be a common failure and a nuisance to replace with all the wires - wrapped round the solder tags and loomed and PVC insulation...

Although the three modules are plug-in, do not be tempted to try replacing a Y amp when powered up. The module won't care but you will get a 320V DC shock between the two pieces of metalwork as you undo the metal retaining screw.

[turretslug]

Hi, and thanks for taking the effort of joining the forum and making the post. Don't get your hopes too high from potty eBay asking prices- some folk have rather odd (and sometimes rather stubborn) ideas of what things are worth. It wastes their time and servers' ! Go by completed listings for a realistic idea.

A couple of decades or so ago, lots of people would have jumped at the opportunity of getting hold of an oscilloscope like this but since then lots of similar specification but transistorised 'scopes have been dumped on the market by educational establishments and ones like this are seen as heavy, bulky and temperamental. It's a shame because at the time of manufacture they were very expensive items and many people who worked in things like TV servicing would have drooled wistfully over something like this.

Nowadays, it's really only folk like us slightly batty lot here who would be keen on this sort of stuff- hopefully, someone here will give it a home. Preferably someone who can collect it from you- many here have woeful stories of delicate old electronics being trashed by couriers and oscilloscopes are one of the most vulnerable items! Good luck,

Colin

[Craig Sawyers]

A CD1400 was my second scope - and served me well for a number of years. Sold it on eBay eventually when I got the Tektronix collection bug.

(My first scope, in my teens, was the boatanchor Hartley 13A. The less said about that the better!)

I think the modular design of the CD1400 was down to an industrial designer called Roy Gray.

Craig

[coil1234]

IIRC these are a genuine dual beam scope, the tube having 2 guns and separate intensity controls.
I remember using these in the Marconi Communications apprentice training school (Test Equipment Appreciation course).
The actual test departments invariably used Tek scopes, with the occasional Marconi TF 2200.

Mike A

[paulsherwin]

Jellybean, do you have some sets of probes for it? It depends on the quality and condition, but you may find the probes are worth more than the scope itself.

[Vintage_RC]

I joined a company that had formed a small electronics operation when I was just out of university in 1968, I was their one and only electronics engineer. I had to make out a list of test equipment I required and the 'scope I specified was the Solartron CD1400 pictured above. It served me very well.

[TonyDuell]

Originally Posted by coil1234

IIRC these are a genuine dual beam scope, the tube having 2 guns and separate intensity controls.

Mike A

They are. Separate Y deflection plates for the 2 beams, but AFAIK only one set of X plates ('scopes with 2 sets of the latter are very uncommon, Tek 555 and 556 being the only 2 I've come across).

I am not sure what plug-ins were made for the CD1400. I've come across :

'Normal' 15MHz Y amplifer
A differential Y amplifier (100kHz bandwidth or something low like that)

'Normal' Timebase
Extended timebase (more slow-speed ranges)
Delay timebase (not as nice at Tektronix's Delay Time Multiplier knob using the second timebase, but still darn useful, I keep this one in my CD1400)
XY plugin. This uses one of the Y amplfiiers as an X amplifier and lets you use the 'scope as a (single beam) XY instrument.

[MotorBikeLes]

Tony, not just Tek, TQ had their D55, later D55A, then D56. All had dual amps, dual timebases and dual guns. This was a few years before the Tek tie-up.
Les.

[terrykc]

Hi Jellybean - you should have an idea of what that instrument was used for by now - even if much of the ensuing discussion will, no doubt, have gone right over your head! Basically, electricity is invisible and the only way to know what it is doing is to use an instrument that draws a picture of what is happening over a period of time.

There is obviously life in the 'scope that you have, so it would be useful, should you wish to sell it, to show it working properly. That isn't as difficult as it sounds because all the facilities you need are in that one box! I can't find a clear picture or drawing of the front and I've never used this particular instrument, so you'll need to do a little detective work.

Somewhere you will find a couple of sockets marked CAL or Calibrator or something like that (ignore the CAL markings on the controls). One socket will be marked 5mV and the other 500mV - we'll use that one. You need to connect that to one of the input sockets on the left. If you have the probes, that will be easy but, if not, a short length of wire will do. There may be a screwed terminal, which will make things easy, or just a socket, in which case poke the bared end of the wire in and use a matchstick or any other convenient object to hold it firmly in place.

Bare the other end of the wire and put it into one of the input sockets. Either will do but, as an example, use the top one. The connector looks like a short length of metal tube with an insulator inside and a small socket in the centre of that - that is where you want to poke the bit of wire. If you fold it back on itself it will, I hope, be a reasonable fit.

Now for a driving course!

First go to https://elektrotanya.com/solartron_c...wnload.html#dl and download the zip file. Then extract the .pdf file for the manual and open it.

Some variable controls will have a CAL position - usually fully anti-clockwise - set them to this position. There is a large rotary switch next to the input - set this to the 200mV/div position (may be marked 0.2V/div instead). Look for an AC/DC switch and select DC. (If you are using a probe, set the switch to 20mV/div.)

Now go to page 6 of the manual, section 5. Skip section 6, which we've already done, and section 9. After following section 10, hopefully you will have a nice trace displayed on the screen!

Good luck!

[Jellybean]

Wow, thanks for all the replies, what a lovely bunch you are! I will try to find it a good home, it's a shame to let these things go to waste.

Originally Posted by turretslug

many people who worked in things like TV servicing would have drooled wistfully over something like this.

Well, that explains it... My Dad was a TV engineer