Wireless of the Week - week 37
 

Developed in 1941, the Switchboard, Charging No.5 was an attempt to standardize and simplify charging batteries that were required to operate wireless sets. Up to that time, charging panels had been unique to a particular radio or wireless installation, but with the 19 and 22 sets then in use, pairs of 6 volt batteries in series were a common power supply with one pair operating the set while the other was being charged by a gasoline generator.

No. 5 Switchboards were most often seen in wireless trucks even if that truck had a factory supplied panel. This was not only to standardize, but in many instances the existing vehicle system was insufficient to operate the more modern wireless equipment and batteries. Also, the No.5 Switchboard could be removed and used from a remote location such as a penthouse or trench if required.

The unit was 18-1/2” wide by 11-1/4” tall by 5” deep and consisted of four ceramic ‘stove’ switches with porcelain knobs set in a bakelite panel. The switch knobs only turned clockwise (lifting and turning counter clockwise removed them) and each switch was protected by a plastic cover. The top left switch determined which pair of batteries supplied the wireless set, the top right controlled ‘internal lighting’ and the two lower ones were to select which generator charged which pair of batteries. Terminal posts running down either side were supplied to attach two pairs of batteries, two generators and output for ‘internal lighting’ which could also be used as a generic 12V DC supply for anything that required it. Two additional posts in the centre were the positive and negative 12 volt output for the wireless set. The bakelite front panel was secured to two wooden battens that were also the mounting points, and the battens to a plywood backing panel. The space between the front and back panels was open so the switchboard was not waterproof.

Shown here is a British ‘Switchboard Charging No.5’ and a ‘Switchboard, Charging No.C5 Canadian’. Note the larger switches and scalloped knobs on the British board. A modified Canadian unit with additional terminal posts was also made for use with the No.19 Amplified wireless set. Noted also is that the British panel used vinyl coated solid core copper wiring which must be one of its earlier uses.

Photograph 4 shows the mounting brackets for the switchboard and in the 5th a diagram from the 52 set manual that shows how it is connected.

Thank you Bruce, very clear and informative info.Cheers. Bob

Did RCA Canada ever publish a manual for the Switchboards, Charging, No. 5C Cdn?

As Bruce noted, brief installation or operational references to this item show up in a number of Wireless Manuals, but was all of this ever consolidated into one publication issued with the Switchboards?

David

I’ve never come across one. I do find this charging board is pretty intuitive in its use and hook up with everything cleanly labeled.

Thanks, Jordan.

They do look very straight forward. Finding one is on my B-List for the 52-Set Project eventually.

David

It's not like the army to not produce a manual, even for the simplest of things. But I agree with Jordan, I have never seen one. It is spoken to in several radio manuals and installation instructions so maybe that's it.

An interesting sidebar. My British panel is a restoration. It had spent its post-war life in the UK at a carnival where it operated the amusement lights and power to the rides which was apparently a common use for them there. Here in Canada they just don't seem to have survived in any quantity.

The only place in Canada I ever saw them for sale was Electronic Surplus in Parry Sound back in the late 70’s. I still have one of their catalogs somewhere.

One of the mysteries in their catalog was a canvas bag of cable clamps for ‘the Fox’. Had no clue what that was in those days.

David

Came across a different version of the Charging Board.

I think that was made for the power hungry Amplified Canadian 19 set.

Or the WS52. I see they've doubled up the battery terminals by the look of things, so it may have been intended for pairs of 12 Volt or quads of 6 volt accumulators that were possible to move by hand without crippling yourself.

(The largest batteries I have are 1950's 6 Volt 170 Amp Hour which are really a 2-man lift, even before you fill them with acid. Next size down is 6v 125AH, then 85 AH, 40 AH, and 16 AH, the last being wooden cased ad used with the Class D wavemeter. In 12V there are the 75, 22 and 14 AH units, all steel cased.)

Modern practice seems to be to fit UK06TNMF 12 volt 110 AH Maintenance Free (Advanced Glass Mat) vehicle batteries for the radio fit, as they can be stored for 6 months once fully charged, or indefinitely if the vehicle is on a suitable "smart charger" - so cheaper for the government to cycle new batteries through stores on a 2-year cycle (test/recharge every 6 months) then surplus them and buy new ones than maintain a battery shop and all the support costs of that.

Chris. (G8KGS)