Internally, there's red rubber "gas" tubing covering
the grid caps., the "homemade" red fibre holders for both ends of the
aerial tuning coil and a hard rubber antenna tuning coil is used instead
of the normal former used in the production model.
There is an extra hole drilled in the base of the power
supply where componentry has been rearranged and a flat wirewound resistor
underneath the chassis in the area of the receive section, not on the
The meter is of the ZC1 Mk1 type, as is the power
supply choke mounted in a square & not rounded box.
The date on the mic transformer box is dated May 1943
while production ZC1 Mk2 sets are all dated 1944.