HW-101 VFO Problem

[mike bryce]

carl...

try the simple things first. replace the 6AU6 tube on the top of the VFO

if that does not clear things up, check the rca plug that goes into the vfo
for a good tight fit.

still problems?

then remove the vfo.

this is not a simple job.

remove the knobs
remove the shaft nuts and washers
unsolder the two wires from the mic connector and remove the connector

loosen the set screws on the vfo shaft. this allows you to pull the front
panel off.

very, very carefully remove the plastic dial. it's very fragile!

the dial is removed by taking out the four screws that hold it to the
aluminum square piece that holds the plastic clutch. there's four small
spacers that the screws go through. watch you don't loose them.


before you remove the vfo, mark its location with a pencil on the chassis.
will save you time when you reinstall it later.

unsolder the three wires, and unplug the rca connector. mark or write down
what wire went where.

when the plastic dial is off, flip the chassis over. there's four
nuts/washers that hold the vfo in place. two are easy to get to. the other
two are up against the chassis and wiring harness between the crystal
 filters.

when the four nuts are removed, the vfo will fall out in your hand.


With the VFO now open, you will see a large ceramic capacitor in parallel
with a polystyrene capacitor.

If this capacitor has been glued to the vfo box, make sure it's still glued
down. if not GLUE the capacitor down flat against the VFO wall.

I use "gloop" for the job..

while you're inside, tidy up any extra long leads and wires.

apply a few drop of teflon base oil to the bearings in the vernier drive.
NOT TO THE VFO CAPACITOR BEARINGS!!!

and while you have the vfo apart, might as well fix the clutch, too

remove the white plastic clutch from the vfo by removing the three screws.
watch for the three binding washers, they're small and you can loose them.

with the screws out, take the plastic clutch off, turn it over and remount
it.

the plastic has taken a "set" over time. by flipping it over, you get more
friction on the clutch.

reassemble the vfo back into the chassis using the pencil mark to realine
the vfo.

add a few drop of teflon oil to the bearings on the second panel mounted
vernier.

install hardware, knobs and enjoy a smooth turning stable vfo!




Mike Bryce WB8VGE
SunLight Energy Systems

http://www.seslogic.com
http://www.theheathkitshop.com

"Electricity at the speed of light"

> From: "Carl C. Miller Jr" <bugmarx at ev1.net>
> Reply-To: "Carl C. Miller Jr" <bugmarx at ev1.net>
> Date: Sun, 13 Jan 2002 11:53:30 -0600
> To: HEATH at LISTSERV.TEMPE.GOV
> Subject: HW-101 VFO Problem
>
> Hello All,
>
> My HW-101 has a VFO problem. After it has been on for about 30 minutes to an
> hour it begins to "jump" frequencies. This is kind of difficult to explain,
> but while listening, to CW for example, the tone will get kinda rough and the
> frequency will suddenly shift, usually upwards I believe, and then shift back
> to the original frequency after a short time and everything sounds normal.
> Sometimes it will do this several times and then finally settle down. This
> affects Transmit as well as receive as it has done this while in QSO with
> other stations. Any suggestions, hints, tips etc. very much appreciated.
>
> Thanks in advance,
> Carl Miller KA5KAB
>
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