R1155A Ser. No. 40696 (cont/)

The tuning scale has cleaned up nicely and an authentic pencil-strip has been fitted. The dubious AF/RF gain control knob has been changed for a genuine one and all the missing labels are now in place. One thing that I have noticed on this receiver is that the band-change knob is permanently slightly out by more than one tooth on the bevel gears. This implies that the hole that has been drilled through the shaft, that holds the pin for aligning the knob, is lightly out. A quaint peculiarity maybe? I still don’t have the pillars and metal strap for securing the Jones connectors, but that really isn’t an issue. Alignment and testing was largely straightforward and uneventful. The radio worked first time ... The moment it was switched on! When I stripped the coil-box and released the cores in the many inductors, I made a note of where the end of the core was in relation to the rear wall of the coil-box. Then when I refitted the core, I was able to screw it back in to (almost) the same position. The only unexpected problem that arose was that the two ceramic trimmers that adjust the high end of bands 1 and 2 had seized. These were replaced with the same two trimmers from the salvaged coil-box. Apart from that, alignment went as per the book with minimal adjustment required. The R1155 was never intended for resolving SSB. On my AD8882B, I have the BFO set for resolving LSB on 3.5MHz and 7MHz. However, on this R1155A, I found that very strong LSB signals on 7MHz were ‘impossible’ to resolve, whilst moderate SSB signals on both 7MHz and 14MHz were resolvable for the same BFO setting. This had me scratching my head to the point that I carefully measured the LO frequency to ensure that I had not tuned it to the ‘image’ (RF - IF as opposed to RF + IF). The Local Oscillator was indeed set correctly on both bands. The BFO was working fine but I was getting the impression that I was not able to bring the actual 280KHz (IF/2) signal low enough in frequency even when the tuning capacitor was fully meshed ... And when I attempted to adjust the inductor in the BFO, the top of the ferrite core came away! I compensated for this by paralleling a small Silvered Mica capacitor (39pF) across the tuning capacitor. This enabled me to bring the frequency lower but I still had problems with very strong LSB signals on 7MHz. However, you have to bear in mind that the R1155 is NOT a modern top of the line contest-winning HF receiver with narrow brick-wall IF filters. There was an HF contest on at the time and it’s at times like these that folk tend to turn the ‘wick’ right up on their PAs, so that would explain the proliferation of very strong signals. I also found that with very careful tuning, I could in fact resolve these strong stations. I also noticed that the fine control on the Type-35 tuning mechanism is actually coarser than the older Type-13 mechanism that my AD8882B has and I am accustomed to, and this was probably why I was finding it difficult to resolve the signals. There is also a small amount of back-lash on the Type 35 mechanisms, and that didn’t help either. All-in-all, I am very happy with this restoration. Another R1155 has been brought back to life complete with fully functional Direction Finding circuitry ... Next on the list ... The accompanying T1154!

The finished R1155A.