Junk Box Parts (9)

Recently tidying up I found a box of old wireless bits and pieces I've had for ages.

Someone must have given them to me and, as several parts look fairly interesting, I've photographed them.

 First, an old multimeter made by Telsen that can measure 30mA, 8V, 16V, 300mA and 240V and it claims to be AC/DC.

I'd need to investigate by detaching the back, but maybe the voltage scales are mixed DC and AC?

 Next some capacitors. Some people keen on restoring early amplifiers love these sort of things, paying lots of money for unused examples.

These are probably from the 50s, but slightly grubby, capacitors, 0.02uF 1000V with Air Ministry code 10C12493

 Unused 0.5uF 500 Volt from the 50s. Radiospares used to buy in parts to their own spec and carrying their own trademark...

They measure 0.62uF/0.56ohms ESR, 0.7uF/0.6ohms ESR and 0.68uF/0.51ohms ESR.. pretty good!


... and a pair of unused 25uF 25V by TCC. One measures 100.8uF at 2.0 ohms ESR and the second open circuit. Too late for a guarantee claim?

This early condenser was made by EBR or Edison Bell Radio of London, is marked "0.002" which is 2000pF.


Here's a useful microphone transformer from Radiospares. Resistances to DC...Primary 3.8Kohm and secondary 1 ohm


A couple of rolls of ancient insulating tape.. not many of these left, I bet


Here's a quarter inch jack plug made by Lotus in the early 30s carrying "PROV PAT" and marked "BALL" and "STEM" and even has arrows to inform the novice on how to tighten the screws.


A selection of switches; simple wavechange and power on/off functions

First a wavechange switch "LONG WAVE" and "HIGH WAVE" helps date it to the 1920s and labelled BULGIN DECKOREM.

Wireless parts were often given weird names... this one's like Latin and it was also the name of an early radio manufacturer in Southampton.


This one's anonymous with only "5" marked on it.. so it's probably a dreaded foreign import..



Here's an earlier "ORMOND"


A pair of Edison Bell coil holders.


A couple of adjustable coil holders for mounting tuning and reaction coils. Neither carries markings so more foreign imports...

In the early days Mr Marconi extracted cash from manufacturers for every wireless part they made... that's only if he could catch them though, hence no name no fee...


Next a few rheostats.

These were frequently in use as a volume control through the simple expedient of reducing filament voltage.

This example from the 1920s has a couple of clever features... an "OFF" setting and an adjustable full "ON" setting, complete with dial and was made by FINSTON, a name I've not come across before; BRITISH MADE so Mr Marconi's had his cut.. The thing is faulty, like many items in this junk box. The resistance of the wire shows 30 ohms but the "ON" end connection is not tight under its securing washer and shows intermittency.



The second (early 30s) is actually a potentiometer (carrying three connections rather than two) and it's porcelain part carries only the code "R2550", so another dreaded foreign part? Possibly not, because further digging in the box revealed an envelope containing a datasheet and metal disk. It was made by Igranic. It's value measured almost exactly 400 ohms.





Another pot, made by RI Ltd and "PAT APP FOR". Looks mid to late 30S?


I need to check on the item below made by "POPULAR" as it has no resistance or capacitance readings across its connections.


This item is a "POLAR RCC" interstage coupling device. Usually, to acheve a decent measure of gain at audio frequencies one used a step-up transformer of say 3:1 ratio or more, but transformers such as this were relatively expensive and not too rubust. The alternative was a mysterious part such as this which is simply a resistor for the anode circuit of the driving valve and a coupling capacitor which connects to the grid of the following valve. It was known as an RCC or resistance/capacity coupler.

This old part has 6.7nF between terminals marked "A" and "G" and 0.144nF from anode to HT. Anode to HT measures 4.5Mohm and the GB terminal seems to be open circuit. Unfortunately this type of component would work when correctly wired up, but in the hands of an experimenter this example seems to have died.

The coil which is visible might be resistance wire for the grid leak, but measures open circuit.

Below is the cover with labelling for the RCC. The experimenter wasn't helped when glue failed and the cover carrying the markings twisted around.



Next, a gramophone pick-up (two views)

above is the socket for the needle with its securing screw, and at the rear the output connections measuring a healthy 4Kohm.


Below a view of the socket into which plugs the playing arm


Now an assortment of terminals labelled L.S.+, L.S.-, Aerial and Earth etc


Finally, some early resistors known as "spaghetti" resistors. I measured them and all were open circuit so I guess the term "junk box" is pretty literal..

Two have markings "300 OHMS" and "5000 OHMS" and "LEWCOS" which stood for "London Electric Wire Company and Smiths". This company made wire from 1909 and were eventually bought by AEI in 1961. I imagine these resistors were made between the late 1920s and the early 1930s?

I imagine this early experimeter had really poor results.


See a few more odds and ends

Return to Reception