HW-101 VFO instability: Coil busted?

[R. L. Blaney]

Hi Jeffery,
Sounds like the tuning slug in the coil may be cracked.  When this happens,
the sharp edges of the crack dig into the inside of the form when the tuning
wand spreads it, and acts like the slug is epoxied in.  Hard to see these
cracks.  If that's the case, it takes a lot of ingenuity to get out of the
problem.  Usually  I try to break it up into small pieces, and replace the
slug.  Good Luck.
73 de
Dick, WB8MHE
wb8mhe at bright.net

-----Original Message-----
From: Jeffrey Weiss <weiss at tds.net>
To: HEATH at LISTSERV.TEMPE.GOV <HEATH at LISTSERV.TEMPE.GOV>
Date: Tuesday, November 17, 1998 5:12 PM
Subject: HW-101 VFO instability: Coil busted?


>Hello,
>
>After receiving much good advice I finally totally disassembled my HW-101's
VFO
>and rebuilt it.
>
>I anchored the big 4700 pf cap to the VFO wall.
>Replaced a small 56pf cap with a 47 pf cap per a bulletin suggesting that
the
>trimmer caps would then
>end up in a favorable mechanical position.
>
>Replaced a tubular 4.7 pf cap with a ceramic NPO disk part after the
tubular
>4.7pf broke. I was unsure whether
>this was a suitable replacement, but in terms of stability and freq
response
>the disc looks good. Not sure
>what  fabrication the tubular cap was.
>
>Crunched the tabs on the Jackson drive.
>
>Replaced both type #44 lamps with #47 lamps (vice versa?).
>
>Cleaned the cheapie rear rotor(?) clamp on the air variable  with contact
>cleaner and tried to lightly compress it with a Channellocks.
>
>Carefully rebuilt the mechanicals.
>
>Good news: The warble appears to be significantly lessened., although it's
not
>perfect.
>
>Bad news: I can't realign the darn thing.  I tried to use the adjustment
tools
>that Radio Shack sells--little
>plastic wands of little substance--and I cannot budge the VFO coil. One
tool
>actually twisted apart in the process.
>
>How much force can I use on the VFO coil? Any reasonable way to loosen it?
Is
>there a better tool to use?
>Should I just get  a CB license for all out of band operation? ;-)
>
>If I can budge it, I believe the recommendation was to adjust the coil at
the
>low freq end and the trimmers
>at the high end?
>
>The though of disassembling that thing one more time is--discouraging!
>
>Thanks,
>
>Jeffrey N0IRR
>
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