BACKGROUND
Wow! Another little "gem" from the past, so far back in time that I am just a little confused about this one!
Sorting through the "lamps & indicators" section of the spare parts shelves and I came across a couple of these lamps ... they are new and completely unused.
The labelling with the packet indicates these are OAK product but although I can remember OAK rotary switches, I don't recall their indicator products. A quick hunt around online didn't produce any useful information so I will just have to assume these are OAK products, probably from the UK as that is where I used to purchase a lot of "bits & pieces" 50+ years ago! That said though, it does appear that OAK was originally an American company but their products were produced under licence in UK - so I really don't know where these little critters came from!
I have made some tests and observations and it is up to the new owner to decide or discover for themselves the usefulness of these INCANDESCENT panel lamp assemblies (and possibly the colour front bezels too!)
OAK - Incandescent Panel Lamp Assembly
I suspect the country of origin is UK or USA, but I am not 100% about this
While the packet these were stored in had quite a few code numbers for this product, I could not find any sensible information online about these - in fact it was difficult even hunting down a UK lamp assembly manufacturer called OAK in the UK - in the USA, yes but I didn't buy anything from USA in those days.
High quality build is obvious after inspecting these.
The Black thermoplastic 'barrel' has a thread with washers and nut for panel mounting. The front end of the lamp assembly screws into this barrel and contact is made with the lilliput lamp using a spring contact inside the barrel.
The terminals at the rear 'could' be Silver Cadmium plated, but whatever the plating is ... these are very clean and shiny! The solder terminals are not the centre hole type but instead shaped at the end so that the hard wiring is wrapped around the terminal.
The front end of the lamp has a TINY (and I mean tiny) lilliput bulb, this is the only component with any markings and stamped into the side of the lamp is what looks to be L A 2 5 - that's it!
The front end has an integral metal thread which screws into the barrel, the lamp does NOT have a thread and "push fits inside this metal thread.
The lamp has a nice single spiral filament, looks very much like tungsten.
DC cold resistance: 9 Ohms
I have tested both lamps, mainly to get an idea of the correctly working voltage/current (usually this type of lamp was designed to run in the region of 20mA ~ 50mA)
With a 6V DC supply, the lamp draws 50mA and the light emitted is White-Yellow in colour of a reasonable intensity.
Dropping the supply to 3V and of course the current flow drops along with the lamp colour changing far more towards a Yellowish look ... it is always a good idea to run these old lamps at the lowest possible voltage-current as this will greatly extend the lifetime of the lamp.
I also gave it a burl at 12V and Yes, the colour produced is far Whiter but I felt just a bit too bright in my opinion! If I was using these lamps I wouldn't be pumping 12V into it.
Actually, considering the age and technology of the time these were produced, I would take a stab at these lamps being designed to run on 5V ~ 6.3V AC - their supply being taken off the heater rail for valves.
DIMENSIONS:
We are talking quite small here ...
Fully assembled (front to rear): 19.4mm length
Front end (White): 6mm length x 5.75mm Ø
Black barrel: 12mm length x 8mm Ø (this is the hole diameter (or slight larger) required to fit the barrel into the panel)
THE BEZELS:
I am not convinced that the two bezels I found with these lamps are actually for these lamps ... 'a lot of water has passed under the bridge' and I just cannot remember!
Yes, the bezel does friction fit over the front of the lamp assembly but this produces a very elongated front end for the lamp - if using the bezel, it would be more practical to mount the lamp assembly back from the panel so that the bezel doesn't stick out too far forward.
In any case, using the selection boxes, you can choose if you would like a bezel included (and which colour), the additional cost for these bezels is Nada Zero - Zilch!
COSMETIC CONDITION:
NEW
Clean
NO oxidisation observed (probably because these were in the sealed packet indicated in the photograph)
I am offering these individually or if both are purchased, a discount is automatically applied. The bezels are optional, just choose your colour (or both) and the cost for those bezels is nothing extra.
