MRG radiogram.

[Geordie McBoyne]

The attachment shows the trimmer locations. The receiver has the standard intermediate frequency of 465Kc/s so the need for bandpass circuits for MW and LW in the aerial input are really not necessary. The medium wave aerial coil has two trimmers, one adjusts the high frequency end of the waveband and the other adjusts the low frequency end of the waveband, unusual.
No bandpass circuits on the short waveband.

Geordie McBoyne.

[Geordie McBoyne]

The 2D13C double-diode is a difficult valve to find.  The replacement for the 2D13C is an American 12H6 fitted on an a special adaptor base, see attachment.   The 12H6 has a 12.6volt 0.15amp heater.  The Mullard 2D13C has a 13volt 0.2amp heater. Resistors have been fitted inside the five pin base to compensate for the slightly lower heater ratings of the 12H6.  A 2.7ohm resistor to drop 0.4volts and a 270 ohm resistor connected between the heater pins of the B5 base.  The ersatz valve can be used in 0.2amp heater chains.
The Mullard Maintenance Manual suggests the EB34 as the replacement for the 2D13C.

Geodie McBoyne.