Restoring an R1155 Receiver
The observant among you might notice that the photograph on the left is not actually of an R1155 but of a Marconi Receiver Type A.D 8882B, which for all intents and purposes is an R1155 in everything but name. Being the commercial version of the Air Ministry Classic, it is probably rather rare since production of the type ceased around 1947/48. Although not absolutely certain, I believe this one was manufactured in 1947. The inspection stamps throughout indicate that it is a genuine Marconi product. I aquired this set in February 2010 for the sole purpose of restoring it. That is, the replacing of all the aging resistors and paper capacitors such that the working performance is the same as the day it was manufactured.
Marconi A.D. 8882B ... aka commercial R1155
Such receivers frequently appear on Ebay, but few are as unmodified as this one was. The only modification at the time of purchase was the removal of the ‘Cube’ capacitor in the centre of the chassis, and subsequently replaced with three modern electrolytics. Even the D.F. circuity was intact! Initial inspection suggested that someone had at some time at least planned to restore it since the top of the ‘piggy-back’ can and Coil-Box lid were highly polished. However, that appears to be all that was done. Much as the metal work was literally immaculate, the wiring was a completely different story! The 1940s rubber insulation on ALL the multi-strand wiring was completely perished to the extent that just touching it caused it to disintegrate. Maybe that was why the previous owner had ‘given up’? There was absolutely no way I was switching this thing on! Designed for instalation in aircraft, the type does not have an integral power supply, so one of my tasks was going to be the construction of a suitable PSU, and since the audio output is ‘headphones-only’, I might as well include a suitable audio amplifier for driving a loudspeaker too, and I might as well make it a valve job.
Around this time, a good friend who I had previously restored an RA17 for, asked if I was up to the challenge of making a working 1155 from three ‘scrappers’. The bonus here was that out of the three scrap 1155s, there were fortunately two ‘cube’ capacitors which turned out to be in good condition, so I would be able to put one back in my AD8882B. Unfortunately like the majority of 1155s, all three ‘scrappers’ had no D.F circuity whatsoever. However, we are confident that all the bits can be obtained through time.
I had a very amusing conversation involving my Mother-In-Law a few days later. We were visiting my wife’s parents in mid February and since several items on which I was bidding were ending that night, I was logged into Ebay. To set the scene, my Wife’s parents are Geoff and Anne, and this is how the conversation went ...
Back home, I tentatively began investigating the wiring in my ‘new’ receiver. There
are actually three different types of wire used; Single-Strand with woven insulation,
Multi-Strand with the dreaded rubber insulation and finally the coaxial cables. Interestingly,
the rubber insulation in the coax cables was in excellent condition. I optimistically
started pulling out the old perished wire and replacing it with modern PVC insulated
wire but soon realised that drastic action was more appropriate. Realistically, like
an old ‘property’, the set was going to require totally rewiring.
Geoff: What are you bidding for?
Me: Bits for a 1940’s wartime radio, the sort traditionally fitted in Lancaster bombers,
for instance.
Anne: Oh?
Geoff: What will you do with it?
Me: Get it working.
Anne: Oh?
Geoff: Then what?
Me: Use it ... Off course!
Anne: You won’t get much on it!
Geoff: Why not dear?
Anne: Radio was rubbish in those days (meaning that there were less radio stations!)
I said nothing, but just gave her a withering look.
