[ICOM] IC-756ProII CI-V DEAD!

[Larry Young]

Bill: Here is a CI-V port test for the ProIII courtesy of John K3CT of the ProIII Yahoo group:

1. Disconnect the power from the radio and insert a blank 1/8" plug into the remote (CI-V) jack.

2. Measure the resistance from the plug shield to the radio frame. It should measure less than ~1 Ohms. If it is open or resistive, replace the TDK ferrite bead on the back of the radio board.

3. Using the blank 1/8" plug again, measure the resistance from tip to shield. It should measure high resistance (>400 K Ohms) if not, Q3772 is likely damaged.

4. For those that don't have the computer case and radio both connected to ground, consider adding the connections so the computer and radio stay at the same potential during lightning or surge events.

I suspect the ProII and ProIII CI-V circuits are the same. The Q3772 number may be different.
Good luck,
Larry K4LXV

--- On Tue, 1/1/13, William J. Wickstrom <jwickstrom at surgesound.com> wrote:

From: William J. Wickstrom <jwickstrom at surgesound.com>
Subject: [ICOM] IC-756ProII CI-V DEAD!
To: icom at mailman.qth.net
Date: Tuesday, January 1, 2013, 4:19 PM

Hello, All:

While operating SKN last night the CI-V data to/from my 'ProII quit (it was
working fine, and all works with my 'mkIIG). I have been able to determine
that the problem is indeed within the 'ProII, and NOT anywhere else in the
CI-V chain. I believe that perhaps some stray RF, or perhaps some other
spike, took out the CI-V in the 'ProII. I have the service manual (in .pdf
format), but could use some guidance as to where to start looking for
faults. Has anyone else had this kind of problem occur? Any help from this
group would be greatly appreciated!

73

William J. (Jim) Wickstrom, W1IK
Technical Director,
Utica/Shelby Emergency Communication Association (USECA)
w1ik at arrl.net
www.usecaarc.com 


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