[R-390] [KA9EGW] progress

[ka9egw at britewerkz.com]

Well, I attacked what is [for me] the scariest thing first--pto endpoint
adjustment.  Piece of cake.  I don't know if my rx is typical, it's a
collins 8719-p-55 unit, but there's an original [anodized bore same as the
rest of the chassis] hole in the exact right spot in the subchassis so if
your screwdriver is the right length and diameter [it is now] nothing but
the endpoint screw cover plug [missing on my radio anyway] need be removed.
I could make another one, or several, if I had the dimensions.  Well, it
took about 20 minutes to get it within a couple-three hundred cps, such that
backlash is now the bigger linearity issue...good enough for now and lots
better than the 5 kc it was off.  [it was 1000.5-kc-worth-of-turns for 1000
kc when I started].

Which creates a new problem.  I have exactly 1000.3 kc from a reading of
x.002 mc to +x.002 mc.  The pto is doing close enough to 1000kc-in-10 turns
for now, but it seems that the 'zero adjust slipper clutch' [dunno the right
name, it's the wave washer thingy the 'zero adjust' mechanism compresses]
well anyway it quits slipping before i can get any closer than reading 2kc
high across the band.  If I could get one end spot-on the other'd be within
a couple hundred cps and I'd be happy for now.  I can easily use the zero
adjust to go to reading 20kc high across the band, then it runs out of range
in that direction too.

It's almost like a gear slipped a couple teeth.  Next I will check that the
nominal 70kc of overrange is even split between the ends of the range.  If
it isn't, what do you guys recommend?  Or should I not worry about it
further at this preliminary pre-resto checkout?

Gads, I hope I explained that right.

73,
Brian KA9EGW