R209 power connectors.

[G6Tanuki]

Rebuilding one of my R209 receivers, I came to sort out the 12V power input; a previous owner had removed the original input connector and wired a length of red and black 2-core flex direct to the innards.

I had thought the original connector was a Belling-Lee "penthouse' socket [so-called because they were used to connect power to the waterproof bulkhead-lamps used in Army officers' tents - definitely Penthouse-grade accommodation compared to what us TA types had to put up with] but having acquired a couple of these connectors they are too big to fit the R209 hole, and have a different anti-rotation mechanism.

I;m wondering what to do - the nearest I can come up with - non-original for sure, but better than a bit of wire hanging out of a hole - is the 2-pin variant of the metal-shell plug/socket with screw-up locking ring - the same style as is often found as a mic connector for CB radios.

Would welcome some other suggestions.

[2000 type]

The original connectors are Belling Lee L1349 series.
Try eBay listing 323788645127

https://www.ebay.co.uk/sch/i.html?_f...45127&_sacat=0

[G6Tanuki]

Interesting... that's pretty much the same as the connectors I have: but the threaded part of these connectors has two flats as anti-rotation whereas the hole in my 209 has no flats, rather there is a cast-in raised portion on the front seating-face which is clearly intended to provide anti-rotation duty.

[2000 type]

Just took a look and my Mk2 has the same "projection" but the original fixed plug which sits just inside but not touching it. Perhaps your anti-rotation flats were filed out by a previous owner to acommodate whatever they put in?

As well as the penthouse lights, that series of connectors were also used on armoured vehicle loudspeaker systems and the ATU switching connector on the Pye C12.

Edited to add: Just looked at pictures taken of a R209 Mk 2 during a complete strip-down and re-finish and that doesn't have any anti-rotation flats inside the hole.

[G6Tanuki]

My 209 simply had the original socket removed and a wire fed through the hole, no sign of the flats having been removed.

The threaded part of my chassis-mount penthouse connector is too big to fit through the hole; even if it did fit through, the projection on the front of the case would bear against part of the shoulder and crack the bakelite once you tried to tighten the nut on the back.

This thread [in Dutch] shows a R209 with a Plessey-plug as the power connector.

https://nfor.nl/index.php?mode=thread&id=253530

and there seems to have been differences in the power-supply with some variants too [the 209-B working offmakins or battery] though mine has a battery-only power supply.

[2000 type]

The Dutch site picture is a R209/2/B which was built with a Plessey Mk.4A plug because the new power supply would run on 12v, 24v or mains.

AFIK the Mk 1s (6v) and Mk 2s (12v) all had the Belling Lee plugs.

[G6Tanuki]

Yes, this one is a 12V Mk2.

I'm wondering if the version of the chassis socket I've got is not the right one? would need a hole at least 1.9cm diameter, whereas the hole in the case is more like 1.6cm.

[2000 type]

It looks right. The Belling Lee sales sheet (dated 2001) shows that the cutout should have anti-rotation flats and should measure 16.4mm between flats and 17.6mm across the wider part (i.e. a 17.6mm hole if it were round).
The main plug body diameter is given as 26.2mm.

Always possible that the details changed slightly from when the plugs were originally produced for the original design. The original 1946 issue EMER shows that the Belling Lee plug was used in the Mk 1.

[G6Tanuki]

Following up on this, the Belling-Lee 'penthouse' connectors I acquired being too-big-to-fit-through-the-hole, I decided to go with the 2-pole Japanese "CB Microphone style' connectors, which fit the front-panel hole and the rear nut also fits into the recess in the back of the chassis.

Tightened up, with a smear of Evo-Stik around the back if the nut/washer to _try_ and make it airtight so there's some chance the desiccator's pink-and-blue-concentric-discs along with a case-purge of dry Nitrogen can result in the thing not shouting "Dry Me!".

From the front it doesn't look at all inappropriate.

[CambridgeWorks]

R209 paired with a cb connector, got to be a first.
BUT, it is practical and works.
Rob

[G6Tanuki]

It may at first seem an incongrous marriage, but I tend to think of these Japanese-CB-connectors [is there a proper name for them?] as the modern equivalent of the Plessey-plug.

Not to suggest you should ever use the Japanese-CB-plugs for mains connection, but in these H&S-aware times you really shouldn't be using Plessey-plugs for mains either!

[CambridgeWorks]

Certainly provide quite a range of pin-outs available. Just need good eyesight and dexterity if say an 8 pole plug is being wired.
I have a small lin-bin with quite an assortment, plugs and sockets, cable and chassis mount, kept "just in case" needed.
Don't think I used any in last 20 years though!
Rob

[dodgy-dxer]

Originally Posted by G6Tanuki

It may at first seem an incongrous marriage, but I tend to think of these Japanese-CB-connectors [is there a proper name for them?] as the modern equivalent of the Plessey-plug.

Not to suggest you should ever use the Japanese-CB-plugs for mains connection, but in these H&S-aware times you really shouldn't be using Plessey-plugs for mains either!

They are often called "Foster connectors"

With different numbers of pins they are useful for many purposes beyond microphones

Fred