[MilCom] repair comments from the workbench

[Duane Mantick]

Some of you might recall that I have been running a Radio Shack Pro-2006 for many years, and that I do NOT use the internal 120 VAC power supply because it seems to run a bit hot and I didn't want that internal heat causing other problems. SOOOOO, I have an external power supply running DC up to the rear panel DC jack.  Inside of radio stays cool, and if the external power supply gets warm, no problem AND if the external power supply goes failure it's a heckuva lot easier to replace.

One weak point - the rear DC jack.  For sometime now, mine had been kinda touchy and if bumped just so would lose connection and radio would shut off.  Finally got worse to the point of "I better do something about this (the power supply transients aren't necessarily good for the radio)".

Opened her all up, and fortunately the slightly older technology of construction (not all surface mount - yecch!) worked in my favor as disassembly even without my service manual (buried somewhere in a box as I just moved) was quite simple.  Problem = one pin on the DC jack had a really crappy solder joint, and wiggling the jack clearly showed the pin moving in the solder.  I unsoldered it and sure enough, there was a bunch of crap like oxidation or something left over from manufacture on the pin. Very likely, this was *never* a good connection and it just took a while to finally break free.  Cleaned the pins and got all the old solder off the PC board, put the DC jack back and resoldered it.  Reassembled the radio and she took off in good order and surprise - with being disconnected for a while from the back-up battery it doesn't seem to have forgotten anything!  Grateful for small favors there.  Another side benefit - the radio sounds to me like it has
 gained a little bit of gain and is picking up slightly more signal with all other conditions being the same.  It is entirely possible that this crappy connection introduced some resistance into the DC power line that may have dropped the voltage sufficiently as to affect the receiver sensitivity.

I'm wondering if anyone else out there has had a similar issue or knows of a history of this.....or maybe mine was just a one-off glitch.

I also took the time to replace the connector from the power supply which was a VERY old version of the Radio Shack "adapt-a-plug", and put on the new end plus then installed the best-fit current style (two pins) adapt-a-plug which was the "M" plug.  Also wondered if anyone else ran across this and had either arrived at that same conclusion or are using a different one.

I can't say what newer units are built like inside but my impression of the overall construction of the 2006 was that it was made to last, and with the exception of one screw holding that PC board in place being inside of an IF cover, ease of assembly/disassembly was obviously taken into consideration.  It was, to say the least, a pleasant surprise.

Duane
central Indiana