[R-390] No Peak on T701

[Barry]

That's a good point; however, why is the transformer slug tuneable?  I
realize that just because a component happens to have an adjustment that's
not a reason to go about adjusting it (golden screwdriver syndrome), but it
would seem they put adjustments on these components for some reason, right?
I assumed the output of the oscillator should be maxed somehow, even if it
is a low-Q circuit.

Although I don't see it in the Y2K file, I do seem to recall seeing
something about adjusting this in one of my other manuals.  I'll have to
check.

Thanks!

Barry - N4BUQ

----- Original Message -----
From: "Bill Hawkins" <bill at iaxs.net>
To: "R-390A" <r-390 at mailman.qth.net>
Sent: Saturday, April 29, 2006 10:30 PM
Subject: RE: [R-390] No Peak on T701


> Ah, les'see, the output PTO coil will not peak.
>
> Doesn't seem like it would be a good idea for it to peak.
>
> The PTO generates 2.5 to 3.5 meggycycles, and they've all got
> to be mixed with the masticated RF from the RF deck. A sharp
> peak at 3.0 MC would seem like a very bad idea. If you want a
> reasonably level signal for 3 +/- 0.5 MC, you want a really
> low Q circuit.
>
> What have I missed?
>
> Bill Hawkins
>
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of Barry
> Sent: Saturday, April 29, 2006 10:23 PM
> To: R-390A
> Subject: [R-390] No Peak on T701
>
>
> I've been doing some more tweaking on one of my R390As.  T701 (output
> transformer from the PTO) will not peak.  I'm getting slightly less then
2V
> peak to peak no matter how I adjust the slug.  Anyone ever seen this
> behavior?  If so, any ideas what's wrong?
>
> I've done some resistance checking on V701 and nothing is all that far
off.
> Since the slug tunes the plate tank, I'm wondering if the problem might be
> with C706.  It's supposed to be adjustable, but how?  Reading the Y2K
> manual, it states C706 is a variable glass dielectric cap.  Not sure what
> that is, but with the PTO out of the radio and the cover off of Z702, I
see
> a clear cylinder in which the slug moves.  Is that C706?
>
> Thanks for any help or advice on this.
>
> Barry - N4BUQ
>
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