[ARC5] BC-459 Drift

[Dennis Monticelli]

Mark,

My T-22 used to have similar symptoms.  It was on a regulated supply so I
immediately suspected the variable caps.   The solution was to clean the
bearings best I could without dis-assembly and then apply 100% DeOxit via a
needle applicator as the final cleaner/lubricator while working the rotor
tuning up and down its travel.  Other chemical combos may work just as
well.  Anyway, that fixed it for me.

Have fun chasing WAS.  I did WAS and DXCC with my T-22 and it was really
fun.

Dennis AE6C

On Mon, Jun 15, 2015 at 6:24 AM, Mark K3MSB <mark.k3msb at gmail.com> wrote:

> This weekend I drove my SCR-274N for a vintage operating event.
>
> I am experiencing some nasty intermittent drift problems with my BC-459-A,
> and it seems to be getting worse.
>
> When I restored the unit, I did general cleaning, replaced the bathtub
> capacitor, and re-soldered all the joints I could get to.  I still had some
> chirp which I wasn’t too concerned about, and drift was minimal.  This
> weekend it got to the point that I decided to pull the 459 off the air (and
> since 80M was dead, brought my operating fun to an end……).
>
> I’m running my BC-456 to the 2 TX rack, but I was not running the
> Dynamotor;   rather I just inserted the output of my HV PS onto the
> appropriate BC-456 dynamotor pins.  I’ve done this before with no
> problems.  Operation of the BC-696-A was great this weekend, and at times
> the 459 was good too (a bit of chirp, but I’m not concerned about that
> right now).
>
> I did notice that when the drift and tone quality went bad, slightly moving
> the tuning knob to a slightly different position would usually clear up the
> problem for a short while.   This tells me there may be a problem with one
> or both of the variable caps in the unit.  Thinking back, I don’t think I
> could reach one of the solder connections on one of the caps, but I got the
> other OK.  So I will concentrate in this area this week.
>
> While I’m in there, are there any other things I should look for that I
> haven’t already mentioned?
>
> I was thinking of regulating the Oscillator voltage with a VR tube, but
> based upon my observations, I doubt this is the issue.
>
> All in all I still had a ball with the ARC-5s!  It’s really amazing what
> they can do.  I picked up 3 more states for my ARC-5 WAS effort – only 12
> more to go!
>
> 73 Mark K3MSB
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