Is anyone likely to be interested in these 'oscilloscopes' [Cardiorater]

[GrimJosef]

I have recently come by two of each of: Cardiorater Type 64 (Cardiac Recorders Ltd) and Monitor C.R.O. Type 1069 B (The Edison Swan Electric Co Ltd). All four units look like they were taken out of active service after long working lives and have since been in storage for many years. They are externally pretty scruffy and one of the Cardioraters has bits missing.

The Cardioraters look like the rightmost of these three http://filmmedical.co.uk/images/stock/img488.jpg. They're rather nicely made inside, as I guess medical equipment has always tended to be. The handful of B9A small-signal valves are missing but there are pencil marks showing what they were. There are also some BCY34 transistors in there with nice long leads. There is a worryingly large number of carbon comp resistors however, almost all of which (I imagine) will have drifted well out of spec by now. The CRT is a Brimar SE5F with a long-persistence P7 phosphor. The datasheet for these starts at PDF page 326 here https://ia801707.us.archive.org/4/it...978Volume2.pdf. The magnetic shield is present too.

The Monitor C.R.O.s are 19" rack units. They're less well made. The six B7G valves are present. There are connectors on the rear and control knobs, along with a voltmeter, on the front. The controls are labelled but none is calibrated. The scope tube is an E4412/E/9 and seems to be identical to the one shown here https://www.vintage-radio.net/forum/...ad.php?t=82190. The magnetic shield is much cruder - just a couple of thin metal half-cylinders held in place by screw clips.

I suspect that no-one will love either of these sufficiently to want to buy them and try to get them working. I wonder whether the parts (most likely the CRTs ?) might be useful to someone though ?

If they're interesting to you, or if you can put anyone who might be interested in them in touch with me, then please do let me know. If there's any real interest then I could clear some space and try and take some pictures of them.

EDIT: By the way, if this is the wrong place for this thread then please do move it Mods.

Cheers,

GJ

[ParcGwyn]

Hi GJ,

I may be interested in the Cardiorators, or 1 of them if there is more interest.


Dave

GW7ONS

[MotorBikeLes]

That CRT was used by Telequipment, , can't remember which offhand (S/D51/52??). One of their early 'scopes was modified for use as a heart monitor, sold under the name of a USA company (a double barrel name, it will come to me as soon as I post this).
Les.
Yes, it did, Perkin-Elmer.

[Diabolical Artificer]

I have a S51 with a Perkin Elmer nameplate and a CRT with a blue phosphor with a suspect CRT, so would be interested, though picking it up would be problematic.

Thanks for posting these GJ.

Andy.

[GrimJosef]

The problem with these tubes for use in real oscilloscopes Andy is that they were custom made with this strange P7 phosphor. It's actually a dual phosphor with a short-persistence blue component which would be fine for a scope but also a long-persistence yellow component which means it's really only any use at very low sweep rates. The yellow light lasts so long - many seconds - that you can see and time a number of heart-rate blips, which is what the Cardiorater was for. But at anything faster than 'very slow' the yellow light will tend to hang around and wash over the blue. There are a couple of nice illustrations of the effect using real P7 phosphor here https://www.youtube.com/watch?v=hZumwXS4fJo and here https://www.youtube.com/watch?v=FCAKL-4NTrA.

I sympathise with your S51 problem. I've got an S51B with no CRT or valves at all.

Cheers,

GJ

[Nymrod121]

'Cardiorater' was very well-made equipment.

My dad was a senior cardiological technician for many years and I remember him visiting various companies (including Cardiac Recorders Limited) on several occasions to look at new products/return & collect instruments for/after calibration.

I recall there was a portable ECG machine (pen-recorder-equipped instrument that ran off a set of PP9s ... it 'ate' them*) - which my Dad brought home for me by way of a 'can you fix this? if not, use it for bits' project.

The circuit boards were populated with OC71s which were the clear-jelly type ... hence they promptly became OCP71s and disappeared into my fledgling 'useful bits' box (these days, it's called a garage).

I still have the aluminium box, also very well made - dark grey Hammerite painted and fitted with an incredibly sturdy leather handle.

Best wishes
Guy

(*somehow, my Philips EE8 set never seemed to need the two flat 4.5v batteries ... I kept finding PP9s appearing every so often )

[GrimJosef]

Just to say that the two Cardioraters left with Dave this lunchtime. I take my hat off to him for making the 4-hour drive here to collect them and then another 4 hours home again .

Cheers,

GJ