[Mike K]

Hi

There are different power supplies . The Mk 2 sets had a large single rotary transformer that ran both the transmitter and receiver , this was not a efficient method as it drained the battery .

To save battery power, the Mk 3 power supply had two smaller separate rotary transformers , one above the other . In receive mode only , the smaller transformer was on .

In the case of the Canadian Mk3 they used a vibrator unit to power the receiver on the set .

I guess you know of the 19 set web site ?

Mike