Wireless of the Week - week 15

[Joe C]

Finally acquired my own example. This one is a near mint (the unit and case interior, unfortunately not the outside of the case) Northern Electric Mk IV* serial number C-1739 manufactured in 1943. More photos at: RCSigs.ca - Fullerphone Mk IV (Canadian)

Now for my questions.....

The plug on my headset has a 'fat' connector while others seem to have a slim connector. Any significance to that?

Meulstee says there were 14,000 Canadian Mk IV and Mk IV* units made in 1942/43 but I've never seen a serial number that high. Bruce's example (original post) is a nice early example from 1941, serial C-329 and appears to be a Mk IV. Mine is a Mk IV*, 1943, serial C-1739. When did they switch from Mk IV to Mk IV*? Did they restart the serial numbers with the Mk IV*s?

Meulstee also says that early models had a Canadian Key W.T. 8 Amp No. C2 but that later units were fitted with Canadian Key W.T. 8 Amp No. C3. Based on my example having a C2, it looks like the change over was with the Mk IV*. Does anyone know at (or about) what serial number the change over happened? Are there known examples of Mk IV with a Canadian W.T. 8 Amp No. C3?