I'm still working on this R-4C that keeps throwing new problems at me as I go along.
I had noticed that I could feel a little "bump" as I rotated the main tuning knob and it was serious enough for the bushing to slip.? The rotation was stiff, as well.
First, the stiffness was resolved with recommendations that you can find in the "Smooth and Silky" article on Ron's page.? Some 1000 grit paper, lightly applied, removed some burrs on the brass shaft and cleared up crud from inside the brass busing that goes around the main shaft.? But I still had that bumpiness!? Fearing the worst, I put on my 4-diopter readers and had a closer look.
The rearmost gear was bumping off a very small mass of crud between the teeth of the rear gear of the cluster gear.? Every revolution, you could see the tension arm move when the bump was hit.? A toothbrush cleared out the piece of crud -- which was easy to see with sufficient magnification.
I'm going to head upstairs for lunch now, then put the PTO back into the receiver and see how it goes.? This receiver has other issues that I don't think I can fix due to design.? This R-4C was the early implementation of the 5-filter design but it uses 6HS6's for the mixers.? With just a signal generator or the calibrator, I get faint birdies from the calibrator/generator about 2 kHz away from the main signal.? It's the strangest thing.? I also can't get it to give me S3 with a 1 uV signal but on the air, it sounds like it has all its "marbles".
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
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