Unidentified bits of test gear

[Techman]

Originally Posted by chriswood1900

I think if you pull on the two round knobs probably about 3/4" you will find they are probes.

Of course you're absolutely right - I think you must have seen one before

Looks like it's all totally made of wood, although the probe stems could be of ebonite.

A couple of 15 watt pigmy bulbs in series when I had a look inside.

I think that the covered hole in the bottom could be to mount it on some device or stand while it's being used, as it doesn't have any electrical connection inside it.

Made by a woodworker for an electrician...it wouldn't pass todays standards.

[Techman]

Originally Posted by chriswood1900

The second post says its a proving unit which usually generates its own voltage to test instruments and I suspect the aluminium can is a vibrator.

Yes, the can is a 12 volt vibrator - I had pulled this out a few weeks ago and confirmed that part of it...it's been opened as can be seen for the usual contact maintenance in the very distant past.

Something goes in that socket/hole in the top, but what?

[Techman]

Originally Posted by Techman

I've found a couple of 'danger' type warning signs in a box that look like they could have come from a sub station.

Well three actually - but two are the same.

I'll have to see where I can put them up to amuse visitors

Edit: Look at that old 4 figure Grantham phone number - that dates it!

[Techman]

Originally Posted by Cobaltblue

The Radio Mail is a Bridge for Measuring C and R

Rotten battery alert (well 'C' cell actually)!

No surprises there. I've found a lot of batteries in items of this gear and they were all rotten and have ruined some of the kit to the point that it's scrap. A lot of the cells were of that same Ever Ready type design date and gives an idea of when some of this stuff last saw the light of day. I think some of this kit hasn't been looked at in decades. It shows signs of very damp storage and the battery rotting hasn't helped, but with a fresh cell and that wire soldering back on it should be right as rain. The black case has been re-purposed from something else and the catch was originally on the side (rather than the end) and it was previously hinged from the opposite side. I found the disc from the bottom of the pot inside the case.

[TonyDuell]

Originally Posted by Techman

Yes, the can is a 12 volt vibrator - I had pulled this out a few weeks ago and confirmed that part of it...it's been opened as can be seen for the usual contact maintenance in the very distant past.

Something goes in that socket/hole in the top, but what?

I believe it was for checking a voltmeter (I've heard it called a 'hot stick') used to test if overhead power lines are dead.

This unit is a power supply that generates a few kV, albeit at a low current. You connect the voltmeter to it and check it reads correctly. Then test the power line, Then check the voltmeter again on the proving unit. If it reads a few kV on the proving unit each time, and 0 on the power line you can say that said line is, indeed dead so you can safely earth it before working on it

The hole is the output socket, the 'business end' of the voltmeter goes in there. There are a couple of interlock switches alongside it which prevent the proving unit powering up unless the voltmeter end is in position.

[Techman]

I removed the rotten batteries from these two meters a few weeks ago with a bit of very hot water treatment, but they've basically had it and the holders had burst the ends out. Fortunately the two Avo meters I got survived, one having no batteries installed and the other where they still had some life in them and had not rotted. We should all know not to put items like these into long term storage with batteries still installed. There's probably a story to tell with this lot, probably a person becomes too old or ill to be bothered anymore and eventually dies, but the stuff gets sold/passed on and we all get the chance to explore the goodies in pictures and (I) make some good use of some of it once again - and the more unusual items get documented for posterity.

[Techman]

Originally Posted by TonyDuell

I believe it was for checking a voltmeter (I've heard it called a 'hot stick') used to test if overhead power lines are dead.

The hole is the output socket, the 'business end' of the voltmeter goes in there.

Thanks for that info.

I've just realised that modern day electricians use a 'modern' version of this when doing EICR testing.

[Techman]

Yet another item.

A Taylor 20B circuit analyser.

There is some previous mention of these when I checked a few weeks ago. How useful one of these would be on a service bench when compared with other gear you might have is debatable. Having said that, it's often surprising how something that at first seems to have little modern day use, then turns out to be the best thing since sliced bread!

It's dead as a doornail. I applied the mains a few weeks ago and there was a very short burst of hash on a nearby radio that was turned on at the time, but that was that, indicating that it's probably the on-off switch o/c from being left in the 'off' position for decades. It measures o/c across the plug pins with the switch on (fuse is OK), so I strongly suspect the usual switch contact fault. This can often be sorted with contact cleaner and working the switch on and off with power applied, although I haven't looked inside it yet to diagnose the actual issue.

It's in fairly nice condition and complete with probe and my favourite period 13 amp white MK plug - worth having for the plug and the magic eye (if it works), although I'm not into breaking things up for parts it they're in nice condition and can be made use of in their original form.

[Techman]

And another one.

I think we all know what this is - an Acton signal generator.

Acorn valve.

There's output, but it's all over the place, so leaking capacitors etc.

I will service this up and get it working properly.

[Techman]

More strange bits...

Home-made, could be some sort of (dummy) load - AF, RF or neither?

Not opened it up to look inside yet, but the test/connecting leads are nice, so worth having just for those alone.

Then there's those Eddystone porcelain spacer type things, which I'm sure will come in useful for something!

[factory]

Originally Posted by Techman

Of course you're absolutely right - I think you must have seen one before

Looks like it's all totally made of wood, although the probe stems could be of ebonite.

A couple of 15 watt pigmy bulbs in series when I had a look inside.

I think that the covered hole in the bottom could be to mount it on some device or stand while it's being used, as it doesn't have any electrical connection inside it.

Made by a woodworker for an electrician...it wouldn't pass todays standards.

I seem to recall mains plugs made from wood too.
There is another on the web search with the same H&C nameplate, seems they didn't get the patent mentioned on it.
https://worldwide.espacenet.com/sear...mond+champness

David

[factory]

Originally Posted by Techman

Here's another one. We know what it is, it's a Wayne Kerr Bridge from the late 40s, but how do you use it? I looked it up a few weeks back and I see that it's been mentioned before, but there seems to be no actual information out there about it. It obviously goes through all its functions, but will probably be out of calibration due to leaky capacitors etc. I was going to take it to an old mate when I next visited him, as he worked for Ekco in Southend when he was young and ended up with some of their old test gear when it was all scrapped and has a similar piece of kit which he still uses, but his is just an inductance bridge and from memory, is a lot bigger physically. He would definitely know how to 'drive' the thing, but he rang me a couple of days ago to tell me that his wife had just died in hospital following a routine knee operation...I'm absolutely gutted for him and can only imagine how he must be feeling at this terrible time, so definitely no playing around with old test gear with him for the moment.

I've got one of those in my restoration queue, I also restored a GEC bridge earlier this year, attached are the instructions for the GEC which may or may not help and the GEC testing one of it's original capacitors.



David

P.S. If you don't want the Taylor 20B consider offering it for sale, it's something my collection lacks as well.

[Techman]

Originally Posted by factory

I seem to recall mains plugs made from wood too.
There is another on the web search with the same H&C nameplate, seems they didn't get the patent mentioned on it.

Yes, I've seen those wooden mains plugs discussed on here, but I don't 'think' I've ever actually come across any myself - and I've seen a few antiquated house installations in my time.

H&C (as shown in your link) certainly go back a long way to the early part of the last century, with patents for lift gear and such in the two individual persons names - latterly to just the two names as a company. I see that the 'sole distributors', Cable Covers Ltd, date back to 1935.

I'm also now wondering if that covered hole in the bottom of the unit was to house some sort of spare fuse, as 1 amp HRC fuses are mentioned on the name plate.

[Techman]

Originally Posted by factory

I've got one of those in my restoration queue, I also restored a GEC bridge earlier this year, attached are the instructions for the GEC which may or may not help and the GEC testing one of it's original capacitors.

Thanks, those instructions may well help - I've saved the image of them for reference. I see yours in an earlier serial number to mine. From my little bit of research, it seems that not one that I've seen pictures of has the same case and some don't have a case at all. I reckon they were supplied as just a rack mounted chassis to be mounted with other test equipment and you sourced, made or adapted your own case to meet your specific needs - or cases may have been an optional extra. Mine has an opening lid and handles on the side, rather than one on the top as most of them do.

[Techman]

Originally Posted by Techman

Home-made, could be some sort of (dummy) load - AF, RF or neither?Not opened it up to look inside yet, but the test/connecting leads are nice, so worth having just for those alone.

Oh dear!

Not what I was expecting.

Well there's yet more battery rot, which although expected, it wasn't expected in this unit, as I just thought it would contain some sort of hefty resistor, although why have the control knob with switch, I thought.

It's certainly a lot more interesting than I thought it would be. For a moment I thought it might be another sort of 'Proving unit', but then there's no external output indication. The terminals are connected to a transformer and I'm thinking it's some sort of oscillator that outputs to a low impedance circuit, the transformer output winding measures less than an ohm. The 'nice' test leads are also not all they seem. They have resistance, either intentionally or unintentionally and both measure a bit over 4 ohms, so it looks like there's something possibly within the croc clip stems.

I thought the perforated board end covers looked like they'd been made from part of an old Philips radio back by the hole pattern, but on the inside I can see PYE Cambridge written and I can tell that the actual wooden case has likely been constructed from the cabinet donated by the same poor old radio.

[ms660]

The porcelain/ceramic bits, starting on mag. page 16:

http://eddystoneusergroup.org.uk/Edd...LL%20PAGES.pdf

Lawrence.

[factory]

Originally Posted by Techman

Thanks, those instructions may well help - I've saved the image of them for reference. I see yours in an earlier serial number to mine. From my little bit of research, it seems that not one that I've seen pictures of has the same case and some don't have a case at all. I reckon they were supplied as just a rack mounted chassis to be mounted with other test equipment and you sourced, made or adapted your own case to meet your specific needs - or cases may have been an optional extra. Mine has an opening lid and handles on the side, rather than one on the top as most of them do.

Mine has a small handle on the top of the case, the case looks original to me, due to the cutout on the back & lack of vent in that corner. I would add some pictures of the insides, but I seem to have forgotten to take any before I took to my storage unit.



David

[Andrewausfa]

My one is s/n 415

Andrew

[Techman]

So the ceramic squares are for making up a cross-fed ladder-line antenna feeder - you'd need a few more boxes of them to make up a long feeder! Looks like they may date from around 1935, there's even a neat round woodworm hole in the cardboard box if you look closely at one of the pictures, the same as all the holes in that valve box discussed in another thread. Interestingly, there isn't any worm in any of the actual wooden items, unless all the really worm eaten items were dumped before the rest was offered for sale.

The last Wayne Kerr bridge shown has a serial number not far behind mine. I note that both of the last ones shown have the same case, and as said, the cut-outs in the back confirm that they are made for the kit. I've seen variations and I suspect that mine was issued as a rack mounted chassis, which someone later acquired and modified a case from a Marconi valve voltmeter to fit. Note that it's fitted with a more modern type mains plug with an 'appropriate' fuse. The earth has been cut off the cable within the plug, so it's been used in anger on live equipment - that's the sort of thing that I used to do with my 'scopes!

[Techman]

Regarding the previously shown piece of homebrew kit as mentioned and shown in posts #30 and #35, I've found that those rather nice test leads have got 500mA fuses fitted in the clip stems, thus accounting for most of the measured resistance - they are nice long leads though, so will be useful for something.

I've removed the innards from the case of the main unit and may apply some volts and see what, if anything, comes out in the way of a waveform. I'm a bit cross that I went to the local Co-op today and forgot to take the latest couple of rotten batteries with me for recycling in their dud battery box, so will have to try to remember next time.