Hello: With the exception of 40M, where the set performs very well, my R-4B has extremely weak or nonexistent PreSelector peaks and extremely weak receive. This happens whether operating standalone or in transceive with my T-4XB. The previous owner installed a small breadboard circuit described on an accompanying hand-drawn schematic as "Improved Product Detector Using MC 1496L," from the December, 1977 issue of Ham Radio. I think that this mod was originally meant for the R-4C, but I really don't know. I also suspect that the previous owner could have only used these Twins on 40M. Again, I am guessing! I have gone through and cleaned all of the bandswitches with Q-Tip and DeOxit, lifting off some tarnish from the circular switch surfaces. Is a complete realignment session in order for my R-4B? Bad crystals? Anyone else have additional ideas?
Thanks in advance, Tom, ABØJ Minneapolis, MN
