[TenTec] Coil values (bandpass section) on VI+ XO/LO board

[Phil Erickson]

Hi all,

  (I hope someone else someday can make use of this VI+ debugging
information..)

  I'm still troubleshooting my VI+, which you can follow by searching the
archive.  In particular, I'm still figuring out why the XO/LO board has low
output drive for the LO on some bands (160/80/40/30), subsequently causing
the BPF mixer to never turn on.

  Right now, I'm focusing on the 40/30 meter bandpass filter section after
the U1 mixer but before the amplifier (Q6,Q7,Q8) and output.  There are two
tunable coils, L1 and L2.  Under the microscope, at least one of these is
definitely broken at its base and I'm sure that results in a very mistuned
filter, which is what is causing my attenuation problem.  I need to replace
it and possibly more - someone was obviously in here with a 'golden
screwdriver' as we found epoxy as well.  The adjustable coils are really
bad mechanically and the core wobbles a LOT when you move it with your
finger - easy to break.

  But Ten-Tec's schematic has no values of the appropriate inductance range
:(  Ugh.

  Does anyone (Gary? Peter?) have info on the designed range for L1 - L11
for the bandpass sections on that board?  I can't find it anywhere on the
schematic and the manual doesn't say either.  It's bizarre that they label
some things but leave this out (?).

Cheers/73
Phil W1PJE