October 2014:

This is the second of two 1155s that I was ‘contracted’ to restore for a friend. Since I had previously restored an R1155E with the Type 13 tuning drive, I figured that the second one should feature the later Type 35 drive. Despite sporting a couple of obvious modifications, this R1155L was an obvious choice; for two reasons. The first being that since the ‘L’ was intended for Maritime use by Coastal Command, it covered a different set of frequencies. Gone is 75KHz to 200KHz while 1.5MHz to 3MHz is added. The second reason for choosing this one was the super-smooth and light tuning action. It is actually possible to spin the fine-tune part of the knob and watch as the pointer continues to  traverse the scale.

Restoring R1155L Ser. 0138 page 1

The photograph on the right shows the condition in which it was received. Note that it came with a full compliment of valves. As well as the odd modification to the ‘Tuning Eye’, one of the two 8-way Jones connectors had been replaced with a different type. The screening cap for the 1st IF valve was missing, but apart from that, the critical components were present. These being the two wave-wound inductors comprising L24 and the transformer that is curiously identified as L23.

Also, the two triple capacitors in the DF circuit had been replaced with six discrete capacitors and the tall 4uF block capacitor had been replaced with a more modern 16uF type. The side plate for the BFO/DF compartment was missing as was the block capacitor in the DF section. There was also an additional capacitor in the BFO section. However, because of its different frequency coverage, this was not going to be a straight-forward restoration. I would have to pay close attention to the wiring in the coil-box and make appropriate notes prior to re-building the set with the help of Peter Holtham’s excellent book on the subject. The plan was also to feed back to Peter for future updates.

Replacement capacitors

Odd Tuning Eye

BFO/DF Compartment