[ARC5] URM-25 Repair

[Robert Eleazer]

I found that simply replacing the bad power switch got the URM-25F running, but that it would not tune, being stuck on a single frequency in the middle of each band, even though the dial spun easily.

After spending most of a day needlessly dismantling the tuning dial assembly I found the problem was a simple as could be.  The shaft that turns the tuning cap is plastic and the attachment to the brass tuning shaft the tuning knob fits onto is simply a spline on the brass shaft with an interference fit into the plastic shaft; it was just spinning in the plastic hole.  I yanked the brass shaft out with some vice-grips, cleaned up the hole in the plastic shaft, applied some E6000 glue and stuck the shaft back in.  I could have done that without all that disassembly.  

Getting the dial assembly back on so to stay within the tuning adjustment capabilites may be a significant challenge, and one that is not covered by the manual.  We will see.

Should you be mentally disturbed enough to try to dismantle the tuning dial assembly, there is no need to do so.  Once the clamp on the back of the shaft is removed the whole dial assembly pulls out through the front easily.   

Wayne
WB5WSV        

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