Hi As you do this, keep in mind that the “common wisdom” many decades ago was to lube the geartrain like crazy. That was what a kid back in the 60’s likely would be told to do. The lube used could be just about anything you can imagine. Just as now kids got their information from a “range of sources” :) :)
Fortunately synthetic lubes did not often come up “way back then”. Many of them are nearly immune to various solvents and cleaning approaches. The idea that they “never harden” may not have taken a 60 year sort of time period plus dust into account. In some cases a pretty involved process could be involved to clean up after some kid from 60 years ago. Bob > On Oct 9, 2025, at 11:31 AM, Jim Whartenby via R-390 <[email protected]> > wrote: > > Thanks Francesco! > > It takes several hours to do a proper cleaning of the geartrain to remove all > of the old grease. I have used WD-40 as a solvent and Krud Kutter as a > detergent since it seems that no one product can remove all of the grime. I > have found that old spray bottles are great for applying the cleaning > liquids. Rinse with water after each application, it will take several > cycles to remove years of crud. An acid brush on a wood dowel is used to go > deep into the geartrain. Finish with a final water rinse and then an alcohol > rinse to release the water. Now a thin wood skewer is used to deposit a > small drop of your favorite synthetic oil to each gear bearing which > completes the process. Do not lube the gears themselves. The less lube you > use the better, it will prevent dust and dirt from fouling the geartrain over > the next 20 years! > > You will be very surprised how easy it is to now turn the two frequency > knobs, I know I was. That "R-390 wrist" will be a thing of the past. Don't > forget to dab some synthetic oil on the guide rollers and bearings found on > the slug racks, they will need some lubrication too. > Regards, > Jim > Logic: Method used to arrive at the wrong conclusion, with confidence. > Murphy > > On Wednesday, October 8, 2025 at 01:59:57 AM CDT, Francesco Ledda > <[email protected]> wrote: > > 👍 > Sent from my iPhone > > On Oct 7, 2025, at 23:20, Jim Whartenby via R-390 <[email protected]> > wrote: > > > > For the life of me, I don't understand why people grease the R-390 > geartrain. The manual even says that it is better to not grease then to over > grease. The group that knows the most about gear works, in general, are the > clock collectors. Their advise is to sparingly oil pivot points and do > nothing to the gear teeth. It will only collect dust and gum up the works, > if you do. As for the R-390 or is it an R-390A? First, test all tubes, > IRAN, second reseat all connectors, then test again. > Regards, > Jim > > Logic: Method used to arrive at the wrong conclusion, with confidence. > Murphy > > On Tuesday, October 7, 2025 at 03:56:50 PM CDT, Adam Morehouse > <[email protected]> wrote: > > Hey guys, > > I appreciate the pointers on my R-392, and now that it's buttoned up, it's > time to work on my R-390. I only tested this briefly when I first got it, > today I threw it up on the bench. Supposedly this was restored by Rick > Mish, it is very clean (except the gear train, which has a lot of fresh > grease...), and the front panel is pristine. > > It does pull stations, but the volume is extremely low in AGC mode, and > gets slightly louder when placed into MGC. > > In MGC, with the BFO switched on, it plays at a normal (not super loud, but > loud) volume. > In AGC, with the BFO switched on, it hums, low volume audio. > > The limiter seems to have no effect, and varying the BFO doesn't do > anything at all no matter AGC/MGC. > > I have Tom's solid state kit installed, and B+ at the AF deck test point is > a steady 180.5vdc. > > I am going to dig out the TM's later on, I have them somewhere...but maybe > somebody here can help point me in the right direction. > > Thanks! > > Adam K2AAM > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
