Carl, My passband tuning knob rotates 360 degrees on my R-4A. It was very scratchy and draggy (metal on metal) until I cleaned and relubricated it. The key was that I was told to unsolder the left side metal cover where it is tacked at the top, front and back. This gave me just enough so I could bend it out enough to clean things up in there. Its still tight, and you can't see great, but you can see enough. I used repeated applications of Q-tips and alcohol and when it still felt scratchy I put a little TV tuner lub/grease on the wobble disc. The 4 tuning slugs (visible through four 3/8" holes in the rear) should be at their maximum rearward travel when the knob is at the 9:00 position. Hope this helps.
KB8BKU , Darryl in Dayton On Jul 17, 2011, at 2:46 AM, Carl Maniscalco wrote: > Greetings to you all. > > I'm new to the Drake world and I just recently traded for a R-4A/T-4X combo > that had sat unused for many years. While the equipment is in pretty decent > shape over all, all of the mechanical elements were gummed up with hardened > grease, oil and nicotine deposits (apparently, a previous owner was a heavy > smoker). I've managed to clean them up considerably and have the PTOs on both > radios working smoothly enough that I can easily tune across the band with > one finger. > > The passband tuning on the R-4A is giving me some trouble, however. The inner > shaft was frozen up completely and I was forced to remove the read panel of > the PBT unit in order to clean the gunk off the shaft and tapered disk free > it up. The problem is that, after reassembly, I'm not sure how how it's > supposed to operate because I've never seen one in woking condition before. > It seems that no matter how I adjust it, it wants to bind up a bit. > > So, what I'm asking is how many degrees of knob rotation should I expect? How > should should the the screw and locknut on the rear panel be adjusted? Should > there be friction or should the knob turn freely? Should there be any end > play? Where should the thickest part of the tapered disk be when the knob is > at the 12 o'clock position? > > Any help will be greatly appreciated. > > 73, > > Carl, KJ6BSO > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
