[R-390] R-390/URR

[Tim Shoppa]

Bob Young wrote:
> >>> I'm working away on 2 390's also, got one running pretty well so 
> >>> far, it really just needed a good electrical alignment, I need a 
> >>> couple of crystals for it. I haven't checked the cams yet though. 
> >>> The bands are uneven. I changed the PTO in the other one, I'm 
> >>> getting severe backlash, not sure why yet, I think the oldham 
> >>> coupler is hooked up ok although it didn't have backlash until I 
> >>> decided that the oldham coupler two sides needed to be closer 
> >>> together after I put it in.
> >>>
> >>> I'll check mine tomorrow for those readings and see what I get on E210.

The most incredibly severe backlash I had on my 390A was when I
realigned the Oldham coupler and neglected to tighten all the set
screws sufficiently. It worked fine for a while. Then,
a few weeks later, all of a sudden the geartrain
would move but the PTO wouldn't, producing some severely disconcerting
results! I did not see the cause until I hooked a frequency counter
up and found that no matter how much I turned the front knob, sometimes
the PTO didn't budge :-).

So frequency counters are, in the case of doofus like me, capable
of detecting the set screw that I forgot to tighten. Never saw that
on the capability list of a frequency counter, huh? :-) (Others
would argue that the frequency counter was detecting a doofus!)

I'm willing to bet your backlash is because you didn't tighten all
the set screws back up after tinkering with the coupler.

Tim.