[R-390] No Peak on T701

Barry n4buq at knology.net
Sat Apr 29 23:22:35 EDT 2006


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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