[TenTec] "Low Note" 221 250Hz Filter Problem

[Peter Hoon]

Jerry, K0CQ,

Nope, there is no jumper across the missing capacitor slot.  It is just
plain missing.

Jerry, according to my translation from the handbook, the missing 102J
small, blue, low voltage, polyester cap is indeed  .001 5% tolerance.

Is my "translation" of 10J correct?

Unfortunately, don't have an exact replacement small .001 cap from my junk
box to try.

Did find a ceramic .001, with a less precise tolerance to try.

Will go ahead and "tack solder" this cap in and test to see if the insertion
loss problem improves, and report back.

Any other ideas?

Thanks,

Peter
VE1CHS

> That sounds like way too large a capacitor for trimming a crystal to
> frequency, and too important to be missing. Unless there is some other
> coupling a missing series capacitor ought to increase the insertion loss
> much more than 6dB. Is there a jumper shorting out the capacitor
> terminals?

> On Sun, 2007-03-04 at 10:23 -0700, Peter Hoon wrote:
> > Fellows,
> >
> > Have the model 221 "low note" 250 Hz 9MHz IF filter.  On my Xceiver, an
Omni
> > 6 Plus, late serial number, it is in the "N-2" position. Am aligning my
S
> > meter with a 50 uV signal from Calibrated Sig Gen as described in
operators
> > manual.
> >
> > Have checked gain jumper (correct), and have reheated all solder
connections
> > on the 221 filter circuit board.
> >
> > All of my other 4 filters are fine, and are properly compensated for
> > insertion loss:  when engaged, and passband is set correctly, I get an
S9
> > reading on S meter.
> >
> > But my 221 filter is one S meter unit low, at S8, or 6dB low.
> >
> > When examining the 221 filter, I note that one .001 5% capacitor (102J),
in
> > series with the third crystal in from one end, is missing.
> >
> > Could someone check their 221 filter and let me know if a similar
capacitor
> > is missing?  It could be that it was the manufacturers intent to remove
the
> > capacitor from this position in the filter. Or, it could be an
inadvertent
> > omission, and thus the cause of the insertion loss by one S unit.
> >
>
> > Thanks,
> >
> > Peter
> > VE1CHS