Wireless Set No. 52 Canadian - Project

[David Dunlop]

Back to this portion of the project once more, to get a couple of things done.

The first will be a close inspection of the surviving wiring inside the switchboard to determine what is still factory correct, and why has been reworked for whatever reason. Fortunately, this task got a lot easier with the help of two members of this forum who took the time to send me some very good photographs of the original wiring inside their Switchboard, Charging No. 5C Canadians for me to reference.

If the two additional pairs of input terminals were not present on this Mk I Switchboard, the rest of the terminals and switches are identical between the No. 5C and No. 5C Mk I Cdn versions of this switchboard. How the additional two terminal sets were actually wired in is not currently known to me, and un til it is, I am not going to mess with them, so my intent at this point is to just replicate what I know to be correct and workable. If and when I can obtain photos of the original internal wiring of an actual Mk I switchboard, or circuit diagram for same, I will go back in and finish this task quite happily.

The first requirement t was to get a supply of solid copper 10 Gauge wire in red and black loom to fabricate the missing wiring from. It took few days for me to remember I had purchased a spool of 10/3 copper wire for some household work a number of years ago. Took a little longer to recall where the heck I put it, and that got real embarrassing when it turned out to be on an open bottom shelf of a cabinet about 15 feet from my work table...in plain sight.

From initial inspection, there looked like 12 wires were either missing, or looked suspect in where they were installed. From the photos I received from our members, the longest wire runs were just a stink over 20 inches, so I decided to cut five 2-foot sections from what turned out to be a 75 metre spool of the 10/3 cable I had on hand. I had forgotten just how challenging it is to unwind the stuff from tightly wound spool and cut it, even with a good pair of shears.

Once the pieces were cut, I had to split open the wire plastic loom to expose the red, black, white and bare copper ground wires and remove them. They are all held together in a rather loose twist, so the next step was extracting the required red and black wires and leaving the white and bare copper for future considerations.

As you can see, these wires have quite a few twists and curves to them once freed up and I needed them to be as close to straight as possible to blend in with the surviving originals. They are also a heck of a lot easier to handle and work with when as straight as possible. I got the last of that work done this afternoon. It took a small bench rise with padded jaws, and some followup palm rolling on a thin dense carpet to get each piece to where I liked it, but I am now ready to open up the back of the switchboard once more and dive into its wiring restoration.


David

[Chris Suslowicz]

Um... hold fire for a bit. Later today (it's 04:00 here) I will drag my Switchboard, Charging, No.5 out of the shed and photograph both sides, plus draw out the wiring diagram and the switching "truth table" and measure the wiring.

It's not the same as your switchboard, but some of the basic wiring should be the same and you may be able to derive the connections for the missing terminals.

(I still think yours is an early Air Ministry version that bears little resemblance to the WS52 or WS19HP (Canadian) switchboard. Mine is intended for permanent installation in a Wireless Truck and I suspect there was a demountable switchboard issued with the "Truck & Ground Station" kit.)

Right now I need sleep.

Good Morning!

Chris (G8KGS)

[David Dunlop]

Thanks, Chris and Sweet Dreams.

I pulled the plywood back cover off the switchboard this morning and started a detailed visual. There are nine factory original, lacquered, cloth loomed wires surviving, all related to the INTERNAL LIGHTING Switch on the upper right of the switchboard, and the BATT, No. 1 ON CHARGE FROM Switch directly below it. Only one is still correctly installed.

The bank of input terminals down the right side of the switchboard all have red, positive leads fitted to negative terminals and black negative leads fitted to positive leads and when I compare to the circuit diagram, not even the correct input terminal pairs have been connected correctly.

The INTERNAL LIGHTING Switch has absolutely nothing to do with the 12-Volt OUTPUT TO WIRELESS Terminals in the centre of the switchboard, yet is the switch the leads for these two terminals come from. Have yet to trace where that mystery circuit ends up.

In addition to this major issue, I can see where at least two negative leads are no longer in their original factory positions and have been refitted to the switches with great creative licence and likely a high risk factor if any significant DC Power was ever applied to this switchboard anywhere.

On the positive side, however, speaking visually, I took advantage of the time looking at the wiring to also map out the terminals on the backs of the four switches for easier identification and cross reference to the circuit diagram. I sketched the layout of the terminals and posted a photo of same below. The identification codes are stamped into the porcelain by each terminal. The three across the bottom are in small, near square, depressions. The three across the top are noticeably larger, more rectangular depressions.

Be interesting to compare how these AH&H Switches in Canadian Switchboards compare in layout and coding to their British counterparts which I recall might have been made by "Arrow".


David