Asking for help, and Exploratory Surgery

Yahoo!

I joined the Yahoo Kenwood Hybrids group and asked about my possible cold solder joint.  A few hours later, I got a response from Terry, K9TW.  He gave me some suggestions about testing the solder connections and what I might need to remove from the radio in order to get to them in order to fix them.

Opening Up the Patient and Prodding Around Inside

So, I started poking around in the radio.  I took the top and bottom covers off and stood the radio on its left side (the "service position").  While wiggling the "problem child" capacitor, I could hear a clicking sound telling me that it was actually moving.  Here is a picture of the loose post:

So, I tried to locate this from the bottom of the radio.  I found it here:

The "Het Osc" board is the Heterodyne Oscillator; it contains the crystals and tunable coils for the various bands that the radio operates on.  Terry said that I would probably have to remove the bandswitch.  It is the middle of the three metal rods extending through the picture.  Removing this one component is an operation that, in itself, is fraught with peril and frustration.  I would also have to remove the HetOsc board and the metal shield next to it.  However, as I looked at the one known bad spot, I realized that I could probably fix that one solder connection by only removing the shield.  If other connections on the relay are also bad, I will then have to remove the HetOsc board as well (after removing the bandswitch).

Which presents an interesting problem.  For the board, there is some solder to remove, and a couple screws.  And there are four posts from the "hanging" HetOsc board (in the bottom of the radio) that stick up through the RF board.  These posts are connected to the RF board with wire-wrapped connections visible from the top of the board.  This picture shows 3 of the 4 connections:

I would have to cut all 4 of these wires in order to remove the HetOsc board.  But, it's basically impossible to re-wrap them, so I would have to clean all 8 connection posts and solder new wire for each connection.  That's 8 more solder joints, in some very tight areas.

So, I want to try to avoid this unless I have to tackle it.

Was this a fancy CB?

Terry also asked me (after noticing that this is a "new-to-me" radio) if I had tested the radio on 10 meters to make sure it hadn't been "hacked for CB".  I think that the CB hack includes replacing the three 10 meter crystals with some slightly lower-frequency crystals and then tuning the coils appropriately.

Of the three highest-frequency crystals on the HetOsc board, I can read the frequency on two of them:

These frequencies match the two highest frequencies on the schematic.  The third crystal starts with "36", but I can't read the rest (I don't have a mirror small enough to fit in there).  However, this likely matches the "36.895" for the 28 MHz band.  So, hopefully, this radio hasn't been hacked for CB.  But I wish I would have tested 10 meters at Ken's house!  We tested 20, 40, and 80 meters - and it was on 80 meters that I found the VC1 problem.  We never went back and tried 10.  Sigh.

So, I've been passing messages back and forth with Terry.  I hope to try the initial solder fix soon, and I also hope to get back up to Ken's house again - there's four more positions on the band switch that I need to try out (one for 15 meters and three for 10 meters).

P.S. Kudos to my Android phone's High Dynamic Range camera mode and my Streamlight ProTac 1L flashlight, which teamed up to take these pictures.  Also kudos to GIMP image processing software, which I used to add the callouts to the first two pictures.