R1132A Mechanical Refurbishment

First a reminder of what the receiver looks like...

The first step is to removed the front panel. Very few of the front panels of these WW2 receivers are in good condition, however all the main parts are present and the front should clean up nicely. The signwriting will pose a problem as it's not engraved. It's turning out to be not easy. Each of the three round knobs is held in place by two Allen screws. These are very rusty and after using oil I was able to determine they are an imperial size of 7/64ths which is around 2.7mm or so. I found a suitable Allen key but was unable to shift any of the six screws. After trying really hard one of the knobs started to crack as the tapped insert began to turn so drilling them out is the only option. Once the knobs are detached and the slow motion drive uncoupled, the panel is held in place by only the nuts securing the pair of handles and the meter needs to be detached. The perspex in the dial needs replacing as it's very cloudy. A couple of years after ceasing this mechanical refurbishment due to stubborn knobs I picked up yet another R1132A (the third) and this was in much better condition... albeit, yet again, with a stubborn tuning knob. Looking into the hole in the knob using a magnifier and a strong light I could see a grubscrew missing half its slot. Because the condition of the perspex scale was so poor the whole dial assembly needed to be taken apart so I could replace it so I pulled and jiggled the knob until it loosened and eventually popped off. The immediate problem now overcome I decided to drill out the old screw. Using a 1mm drill I made a pilot hole which I drilled through using a slightly larger drill and was pleased to see brass swarf and then the drill went through and I could see for a nice change the hole was dead centre in the old grubscrew. After tapping the hole 6BA I used a half inch flat headed 6BA bolt rather than a grubscrew.

The tuning knob design is slightly odd. The centre is a steel plate crimped through the knob with a short cylindrical tube finished with a chrome plated end cap. The tube has the threaded section for the securing screw. Once the knob has been detached three screws are removed from the escutcheon to reveal the dial which is in an acceptable condition.

Note above.. the original dial glass was a thich perspex which was still pretty clear but had been bashed and was split and anway had shrunk cracking its securing holes. This was secured by only five 8BA screws but the replacement made from thin transparent plastic needed to be superglued to keep it flat. This then is the 3rd R1132A, in much better order than the first two which were both converted to the 2m amateur band and ideally suited to restoration. The restored dial assembly looks very nice and the tuning works smoothly since the gears were cleaned and greased. Under the dial the paint is a smooth grey finish but as you can see both this example and in the 2nd pictured above the paint has oxidised and turned into a matt finish.I used a second piece of thin plastic to cover the logging data. The original perspex had warped and shrunk by about 5mm.