Wireless Set No. 52 Canadian - Project

[David Dunlop]

I finished doing all the Resistance Tests for the Supply as whole and the Vibrator Supply, and have also written up specification sheets for all the resistors and capacitors in the unit. And some things do need looking at.

Starting with the Vibrater Supply, there was an interesting surprise when I looked under it shown in the first photo. Notice the long, grey, 10 Ohm resistor near the bottom of the image. This is not a factory original part and does not show up in any way, shape or form in the manuals. I initially thought it was a bog job but as I thought about it and made inquiries, the Modifications List for the 52-Set surfaced in discussions and it turns out this addition was part of Modification No. 4 covering required changes for operation of the 52-Set in the Arctic.

Turns out that in very cold weather, the 0Z4 and 0Z4A valves will just stop working. The fix was to switch to a 6X5GT valve, however, the filament voltage in it is only 6.3 Volts DC. This 10 Ohm, 10-12 Watt Wire Wound resister is connected from Pin 2 of the 0Z4 Octal Socket to ground. Pin 2 it not used for the 0Z4/0Z4A, but is the Heater connection for the 6X5GT. The resistor reduces the voltage from 12 to 6 Volts so the 6X5GT will run quite happily in extreme cold.

This mod was done to my 52-Set 12 June 1966 so it must have been going up north somewhere for a while. At that point in time CFS Alert and CFS Inuvik were the only two permanent arctic posts for the Canadian Military. Alert was RCAF and Inuvik was RCN. However, 1966 was also the start of the Canadian Governments experiment with unification of the three armed forces, so I have no idea what equipment might have been in those two stations at that time and thereafter for a while.

The second photo shows the location of the two resistors I need to get at to test. The lower one with the orange band is reasonable accessible but its twin is hidden under base plate of the large coil roughly centre in the photo. Fun times ahead me thinks.


David