[Icom] Icom 2100H Transmit Crackle/Static Fix

[Linden, Mike (BRC-Hes)]

  I'm not sure if this subject has already been addressed here or not, so
here goes. My 2100H has been generating a crackle/static noise from the
speaker on transmit for at least a year or so (it can be really annoying).
It seems to get worse at higher power levels. The only reference to the
problem I found on UseNet was that it might have something to do with the PC
board mounting screws being loose.
  
  I decided to pull the radio out of the car the other day while installing
a new mobile speaker. I found the screws on the board to be fairly snug.
Regardless, I placed star washers under some of the screws and tightened
them all down.

  I also noticed that one of the two solder bridges that connect the ground
side of the SO-239 to the board looked like it was cracked. I reflowed the
solder on both of these solder bridges (the SO-239's center conductor
connection looked fine) and closed-up the rig.

  The crackle/static problem I had on transmit is now completely gone (even
on high power). If you have this problem and are thinking of doing trying
this fix, I would make the following suggestions: Use star washers that are
small enough that they will not short any nearby traces to ground (some of
the PC board mounting screws have small traces nearby). The gaps between the
SO-239's ground "pins" and the PC board look like they might be as large as
an eight of an inch or so. This is a pretty big gap to be bridged by solder!
In retrospect, I probably should have run a small piece of stranded wire
across the gap to make the bridge more robust -- I'm sure these solder
bridges are seeing some stress due to thermal expansion/contraction.

  I hope someone finds this helpful!

  -Michael, N9BDF