If the screws are going in so far that they fall out the inside of the knob,
it sounds like a sleeve is missing or something like that. Compare the
diameter of the rod onto which they mount with the diameter of the hole in
Specifically, the set-screws in the main tuning knob are indeed tiny in
diameter. I don't know their length.
----- Original Message -----
From: "Tom NØJMY" <email@example.com>
To: "Discussion of Ten-Tec Equipment" <firstname.lastname@example.org>
Sent: Friday, June 12, 2009 12:32 PM
Subject: [TenTec] Two Century 21 problems
> I'm going back together with the first of four Century 21's here. First
> off, is it me, or are the set screws in the main tuning knobs really
> tiny? Such that the threads in the knob are excruciatingly fragile? I
> haven't got one out of the four that will tighten enough to stay secured
> to the PTO shaft. A couple of the screws can be pushed right through.
> Any thoughts on a simple fix for my simple mind?
> Second, and more serious. I had one up and running yesterday on 20
> meters. Seemed to have good sensitivity, maybe even above average. So
> I plugged in the matching calibrator which put in a deafening
> signal...for awhile. As I tuned to zero-beat the audio quit completely.
> After monkeying around with it for about twenty minutes without plan, I
> switched the selectivity control from narrow to the middle position and
> pop, the audio came back. On all three bandwidths.
> So I turned the RF and AF controls way down, turned the calibrator back
> on and started increasing the gain. Like an idiot, I can't remember
> which one, maybe both - arrgh! The calibrator had plenty of signal all
> the way to the top of ten meters.
> But as I continued to increase gain, poof. No audio again. It wasn't
> near maximum gain either. And this time it hasn't come back.
> What would cause this behavior? And any ideas where I should start my
> trouble-shooting? Being primarily a boat-anchor man, I can use all the
> help I can get.
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