[R-390] Signal Generators, et al

[Roy Morgan]

On Jan 14, 2011, at 2:32 PM, nryan at mchsi.com wrote:

> ...  Sure, the AN/URM-25D is a pain to zero in at higher frequencies  
> due to play in the gears.  Has anyone tried eliminating the slack?

The URM-25D has a single ball bearing at the rear of the tuning knob  
shaft. If the mechanism that takes up the slack in the shaft is worn  
or out of adjustment, pulling and pushing on the tuning knob will  
change the frequency.

The cure it to tighten up the bearing seat. Be careful not to lose the  
bearing by loosening the thing instead of tightening it.  Gentle  
tightening of the lock nut, followed by a cleaning and a spot of  
finger nail polish will hold the mechanism in place.  (Do all this  
after a good long warmup.)

Roy

Roy Morgan
k1lky at earthlink.net
K1LKY Since 1958 - Keep 'em Glowing!