[Milsurplus] BC-348Q IF Alighnment

[Bill Carns]

The injection Osc. is inserted into G1.  G3 has the input from the signal
path which involves the tuning capacitor.  I would think that G3 or that
tuning cap is where it could go. There is a coupling cap in-between G3 and
the tuning cap itself, but it should be able to go on the cap terminal.  I
have never done it, but am about to.  I have a very good (or was) BC-348Q
that I let sit and now has leaky caps, so it is time for the invasion and
alignment.

Bill Carns, N7OTQ (Trustee K0CXX)
Past President, Collins Collectors Association
Founding Board, Collins Radio Heritage Group
Editor, Signal Magazine
Wimberley, TX
512 618 2762  (Cell)
512 847 7010  (Home)





-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of
John Watkins via Milsurplus
Sent: Sunday, January 03, 2016 4:25 PM
To: Mil Surplus <milsurplus at mailman.qth.net>; Army Radios
<armyradios at yahoogroups.com>
Subject: [Milsurplus] BC-348Q IF Alighnment

Currently going through the IF alignment chart (915 kHz) and the 3rd and 2nd
IF peak up just fine, good audio on the speaker and Tek. 475 scope.  The 1st
IF is a bit confusing as to the input of the 915Khz.  The connection is
supposed to be made on the VT-150 (6SA7) 1st detector.  No pin is given as
the socket is inside the Osc. can.  All that is given is to input on the
control grid external terminal.  Problem is that the control grid is
normally the first grid after the Cathode as I understand it.  That is pin 4
on the 6SA7 and that pin has no external connection except to the band
tuning cap 1d. Is that where the 915Khz is injected?  Never was great at
pentagrid converters.

TIA,

John WD5ENU   
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