The bandswitch on a Philco 45, 29 and one or two others has an annoying tendency to seize up. Although the usual advice is to be patient and clean out the dried dirt and gunk inside the shaft bushing, I have had very little success over the years doing that. Does anyone understand exactly why this part often goes south in this particular way?
Mike AB3CX
Could be the switches contacts points are old & worn out beyond cleaning repairs? Just a guess tho. Sometimes, vintage "all orig" parts must be replaced, even tho it takes away from originality of the set to keep the bandswitch operating into the future, or have a pro switch-rebuilder repair your orig switch. Yes,.. there are guys out there that offer these services! I usually just find a comparable switch & replace it from junk chassis' or spare-parts boxes when needed. Close visual-inspection of your orig bandswitch and continuity checks would be in order of the contacts-points.If replacement is necessary, its somtimes abit of a chore making the shafts fit the orig knobs on rotary-types, but abit of trial & error can get good results using shaft-couplers when acceptible, has worked for me. Just my .02
Here is what I would do, but only as a last resort, make a diagram of where everything is connected to that bandswitch, coils, wires, resistors, condensers, etc, then disconnect everything and remove the switch. You can then work on the switch without anything getting in the way. There are a couple of things you could try, I would wash it with a TSP solution to get rid of the dirt, then I would soak the assembly in Varsol to dissolve any old grease,clean the Varsol out with alcohol, then oil the bushings. Another thing you might try is tuner bath or carburettor cleaner. If it still won't free up then you may have to disassemble the switch, which is not always possible. Replacement often isn't a viable option especially with the stacked wafer affairs, in almost every case you will have to find a replacement bandswitch from a junker chassis, generic replacements generally won't work.
Best Regards
Arran
In models that old I suspect there's some expansion going on due to impurities and or dissimilar alloys in the metal pieces. Kroil seems to be pretty good for freeing them up although some remain somewhat tight even after they break free. Its usually not the fault of dried grease - that would be easy!
I've disassembled some later era ones - particularly those with an aluminum shaft - and found them very corroded inside the bushing. IF you can get the shaft out of the bushing its an easy fix.
I've been there; done that. It appears that the vendor, who supplied Philco, used a lubricant on the shaft, in the bushing. Well, it seems that the lubricant has turned to glue, over all these years, and you can't move the shaft with an impact wrench. This was on one of my sets; a Philco, of course. I had a Weller soldering gun, with a broken tip. I took the two ends of the tip, and touched them to opposite sides of the threaded bushing. This works best if the nut is off, and the bushing receives all of the heat. I had a knob on the shaft, and as I heated it, and the shaft began to turn. The switch won't turn with the nut removed, because it's keyed to the chassis. From there on, you can put a little squirt of alcohol, to dissolve the old lube, then put a little drip of 3 in 1 oil, and you're good for another 70 years.