[R-390] Interesting Problem

Ron.K3PID ron.k3pid at sbcglobal.net
Tue Dec 7 13:30:29 EST 2021


So I was shutting down the rig last night and noticed that the R-390 
didn't go dark as it usually does! in fact the OFF position on the function switch didn't 
have any affect on the radio. A quick check with an Ohm meter showed that the 
contacts P118-11 to P118-2 was closed for all positions of the switch. OK! 
Removed the front panel and observed that the cam was indeed pushing the 
microswitch in when in the OFF position. Looking around for an easy way to get 
the microswitch out I just happened to notice that the solder blob on the 
center pin on the switch was just barley touching the unused ( assume Normally 
Open ) pin. It was pretty easy to carefully bend the unused pin away from the 
center pin and Viola! Problem solved!!! Just to be sure I put a piece of heat 
shrink tubing over the unused pin. Now I have never had the front panel off 
before but I have only owned the rig for about 20 of its 65 or so years so I 
don't know what any previous owners had done. It's pretty hard to imagine how 
the wiring harness could have been pulled down enough to get those two contact 
pins to touch but that must be what happened. Why it happened now is a mystery 
of course but all is well that ends well I guess...  While I have the front 
panel off I think 
I'll use a little contact cleaner on the rest of the switches etc. They don't 
look "dirty" but should I clean and lube the gear train before replacing the 
front panel? Recommendations?

Ron K3PID


More information about the R-390 mailing list