It's that well known item, the "multipurpose part" and was used with a lot of sets.

It's Voltmeter, Pocket, 250 Volt, No.2 ZA.7372 and the matching case is ZA.7369.
They were standard issue for testing HT and LT batteries, plus valve electrode voltages on sets such as the R107 that has a test panel fitted to the front. (Also for general faultfinding on sets like the R109.) They are not a particularly brilliant meter for this purpose, having a sensitivity of 500 ohms per volt, and at one point there was a shortage of suitable meter movements which led to the issue of the Voltmeter. Pocket, 250 Volt No.3 with 350 ohms per volt sensitivity, and correction tables for various working instructions with the corresponding (lower, due to the extra circuit load) "nominal" readings when testing the set.

They turn up at amateur radio rallies fairly regularly in the UK, and tend to be dismissed as "useless junk" and are therefore cheap. Unfortunately the plastic (celluloid?) windows tend to degrade and make it difficult to use - though it's not difficult to replace them with a piece of sheet perspex/plexiglas of suitable thickness.

Chris

meter
 

Those meters with the test probe directly mounted on the meter , are primarily meant to used with a test panel . I cannot imagine anyone using those meters by placing the meter and its probe directly onto the valve sockets , which are mostly inaccessible and surrounded by wiring and other components . Most of the smaller valves I've seen have the anode pin on the base , the cap is , if present , is usually the control grid . I think a multimeter would be of more use for servicing wireless sets . The famous AVO meter perhaps ?

I only know of the 11 set having a test panel . The R107 sets are just not seen over here .

BTW the Australian version of that meter was made for the 11 set specifically . The Aust. meter isn't listed in any other wireless set parts list as far as I know .

Hmmm...

Having just looked at the R107 working instructions it gives the expected cathode voltages using an Avo Model 7, so you may be right on that score - I remain convinced that the R109 was issued with the pocket voltmeter for faultfinding, but the voltages were measured on an internal tagboard; I shall have to dig for that manual.

My WS11 manuals list the pocket voltmeter and its case, with a footnote stating "Normally carried in Cases, Spare Parts, No.5B". The manual is dated 22nd Nov 1939 and internally notes"January 1939, amended 20th January 1939, revised and reprinted 10th February 1939". It has an addendum sheet in the back that shows the pocket voltmeters to be worse than I first thought! (23rd November 1940) ...it has become necessary to decrease the resistance of the Voltmeter, Pocket, No.2 from approximately 300 ohms to 125 ohms. The new type of voltmeter will be designated Voltmeter, Pocket, No.3...

It then gives a table showing the different readings for each test point if the No.3 is used.

The pocket voltmeter may well have been introduced for the W.S.11, but I suspect it was found to be a very useful tool and found its way into a lot of kit.

Earlier sets (W.S.1 and W/T sets (various)) had "Voltmeter, Pocket, 'x' Volts", where 'x' was specific to the set (6 volt or 60 volt, etc.).

Chris.
[1] On which note, Plate 13 looks quite legible and it might be possible to transcribe the text on the R.H. door of the charging switchboard.

The bottom 3/4 of the instructions are word for word from the WS 11 manual. The top paragraph is a bit harder.

Switchboard Charging No 1
WORKING INSTRUCTIONS
The switchboard No 1 is connected to the
wireless set no 11 by means of the two wire
"plug-socket" provided. The leads from the
switchboard charging terminals should be
connected to the battery pole leg , ????? taking
care that the polarity is correct. The batteries
should be connected to the switchboard by the
leads and "Niphon" plugs supplied.

I'm unsure of the italics and the question marks.

plugs
 

I do have a couple of WW2 Niphan plugs , the British ones - they do plug into my ww2 British batteries . I should do a drawing of the plugs . I believe the company is still making plugs NIPHAN in the uk .

BTW the Aust. WW2 era niphan plugs are different, they will not plug into the British sockets . My 1943 dated British battery box drawings are on this forum somewhere .

I found those WW2 wireless set acid batteries out in hughes yard Coburg .

This guy has a niphan plug , and that test meter as well .

http://www.wwiireenacting.co.uk/foru...p?f=42&t=76556

Charging Switchboard No 1
 

I picked up some stuff in town to reproduce a switchboard. The panel piece is 12" square and the sides are 3" deep. I guessed that the panel is recessed 3/4" and went from there.
The toggles on the switches are the same size and shape as an ordinary household light switch. The bolts that hold the cover plate to the switch are the same spacing as the top switches on the switchboard. Some hardware strap hinges are the proper size too.
I ordered some nylon shoulder washers and knurled thumb nuts off ebay and am watching for some 25 amp or volt gauges to show up. There's quite a few outfits that made analog gauges that would work.
The terminals for attaching wires are 1/4" NC by the look of it.

I am also looking at making the metal cabinet, even if I just stick a picture of the switch gear inside for now. :) So I guess the hight measurement of 16 1/4" must include the strap at the bottom. Can I query why you made it 12" and 3" instead of 12 5/8" and 4"? Studying the picture seems to show that the doors have about a 1/2" rounded edge, which would add up to the stated depth of 4 1/2". Can I also ask what thickness of material you are using? I am guessing at something like 12 gauge? So 2 -2.5mm sheet. Regards Ron

Instructions
 

I deciphered the instructions that go on the charging switchboard's door and came up with a pretty good rendition. This picture is actual size and can be printed on some plastic and riveted to the door. It needs a legal sized printer though. It uses 6 rivets.
Ron, the 12 5/8 includes the hinges and the height includes the mounting lug. The depth is the 3" sides plus the 1" doors plus the hinges. It all works out OK. The material is 1/8" or 11 gauge. They must have wanted bullets to bounce off it!
I think the doors just have the edges bent by a break and that gives a bit of a rounded corner.

Ah that answers my queries David. I'm just gathering facts and figures before I make a start. I'm also trying to decide what is happening in the middle where the doors meet. It looks like the left door has a rebate with a flat for the right door to sit on top of? Have you got a better picture of the front than the one I posted? Cheers Ron

box
 

Looking excellent I must say . David is making another two , for us Ron :cheers:

Its amazing what u can buy in hardware stores

I had a loan of an original cab 12 battery box , sits between the seats in the cab - I went ahead and made a repro box . Anyway , the locking catch on the lid had me worried, where to find one . The hardware store in Warragul had the identical catch , 60 years later and you can buy the exact same thing . I guess a nail is a nail and a bolt is a bolt

That would be nice Mike :note: David I'll PM you with my email address. I'm not having any luck down loading those four pix at the correct size. Ron

I printed out an inverted set of pics of the panel and they're easier to see some stuff. It was then just a matter of taping the images to the panel and centre punching the holes. No measuring required. I drilled through paper and all so no mistakes in hole sizes. Slicker 'n snot!!!

I got this wire reel off a forum member. It's the same as the 11 set one except it doesn't have the brackets to hold the connectors.

nice
 

neat idea ..................................

connectors
 

I have some spare connectors if you want some

It's starting to look the part. I have about 7 hours into it so far. The ends on the wires that go to the set are offset almost half an inch so the terminals stick out about 1 1/4 ".
There's 4 bolt holes below the bottom gauge that must hold the condensers on the inside. Now to make the switch mounting plates.

Great stuff David and thanks for the pictures you sent me. I'm dead interested in what you do with the doors. Ron :thup2:

Not wishing to rain on your parade, but the original unit most likely had a plastic (ebonite or Tufnol) panel with the lettering engraved on it. The terminals would be uninsulated and probably BA thread with all the (electrical) metalwork being nickel plated.

Chris.

The unclear part reads "Carbon Pile Regulator".

It's also "Niphan" with a 'a' (but you have to know that in advance (grin)).

Niphan connectors are still in production, but the modern ones are either plastic or stainless steel, I think. (Also the company is only interested in large commercial orders and Defence contracts, and completely uninterested in sales to the general public.)

Chris.

My measurement of the terminals on my 19 set switchboard (approximately 1/4-25) suggested BA threads and the 0BA nuts I ordered fit perfectly. Since a 11 set component should be earlier than 19 set, it seems reasonable to me that an 11 set switchboard would also be BA threads. My source for the 0BA nuts was http://www.britishfasteners.com/inde...0ba-steel-3665

Chris, in the instructions it says the captive screws holding the panel in place have to be tight because they form part of the electrical circuit. Therefore the panel must be metal. The only part of the circuit would be grounding for the two condensers that are attached to the back side of the panel.
Thanks for deciphering that part of the instructions.
Those lid catches have me scratching my head. They don't look to be spring loaded. Maybe that's why the bottom one in the picture isn't latched. Gravity took over. The catches must be made of spring steel to hold some pressure to not fall open.

I suspect the panel is plastic, simply because it would be a lot easier to manufacture that way, and be safer to connect up - touching a battery lead to the panel while connecting up would not cause a short circuit - also it would be more rigid than a thin metal plate. They tended to use uninsulated terminals in non-conducting panels a lot, also it allowed the labels to be engraved and paint filled, rather than having separate labels made and screwed on, and the screws on those cable clips at the bottom would have to go into tapped holes (because nuts on the back of the panel would be impossible).

The condensers will be the block paper type, with mounting lugs on the bottom and probably stud connections on the top.

I think the panel retaining screws have to be tight because there are connections via them between the case and the circuit - if you look at Figure 16 there's a wire to each side from the Regulator (left) and Set (right) negative terminals.

I have some spare parts and spare valve cases for the WS19 and WS18 with that type of retaining clip instead of the toggle clamp variety (also the "spring clip & stud" "hook and stud", etc. There were a lot of variations according to the different manufacturers).

Chris.

If anybody is looking for a counterpoise, this outfit has some for sale

panel
 

Would a ebonite panel of that size, have enough structural strength ? With all of those holes for the meters and the terminal posts and the rest , a ebonite panel would be rather fragile and prone to cracking . Mike

pic
 

this may help .............

Plastic or metal? I was thinking along Mike's lines. Plastic in the late 30s stuff was restricted to small parts likely because of the strength issue. That panel is held in place by 2 bolts 10 inches apart and near the edges. The weight of the cables is all hanging off the panel too and would get flopping around in rough conditions.
Chris, have you got a picture of one of those catches?

There's plastic and there's plastic. The Switchboard, Charging, No.5 used with the WS9 and WS19 is made from a single sheet of some black plastic and it's probably almost twice the area of the item under discussion. I think it's about 1/4" or 3/8" thick, and secured to two wooden battens (for mounting to the truck) by a couple of woodscrews.

I'll try and get some detailed measurements tomorrow, and photos of the catch (which appears to be spring brass on one of the spare valve cases for the WS38).

Chris.

Chris, you're right but did they have both those kinds in the late 30s? lol By the mid 40s plastic had advanced by leaps and bounds!
I got one switch mounted today. When I'm done and paint stuff black it'll look the same whether plastic or metal.
I've been pondering the construction of the doors. In our picture of them it almost looks like the edge of the left door is bent funny but I'm not sure. The light is coming from the right so the black line you see has to be the gap between the doors.
I'm going to make the doors out of 14 or 16 gauge. They wouldn't be heavier or they wouldn't need the edges folded back that inch or so. That open catch hangs down over an inch so it has to be mounted an inch and a quarter or so back from the face of the closed door. That makes the door an inch thick. The doors will look like a shallow box.The doors don't overlap the unit's sides or they would tangle with the hool up cables.

I made some similar observation in my post #129. But I still don't think the doors look 1"? I'm more inclined at about 1/2"? Ron

I have now scanned everything I have as big as poss. Hopefully for the slightest detail. Ron