Subject: IC229H. CPU RFI



Hello From Mike, N3KCT !



For those owners that have encountered CPU RFI from your IC-229, Here's

the fix!



   The problem is cured by properly grounding  the CPU/Display board.



First remove the top and bottom covers.  Then carefully remove the threaded

mic connector which fastens the mic jack to the front panel.



Remove All Knobs and then the four screws that hold the front panel onto

the metal chassis.  This exposes the clear display housing and CPU board

when you slide the front panel off.



There will be three screws that hold the display panel along with the CPU

board onto the main chassis.  Two are next to the mic connector, and one

is next to the channel control knob.   Remove these three screws and the

entire display/CPU section will come off in one piece.  You will not have

to disconnect any of the wiring.



Carefully clean the ground traces that these screws go through on the back

of the CPU board and tin them.  They are around each screw hole on the CPU

board.  When the radio is re-assembled, these traces will now properly

ground out the CPU section and cure your RFI problem.



Appearantly something happened during manufacture that caused these to be

covered with that "clearcoat" stuff to prevent them from grounding out.





This fix has been 100% effective on mine and several other radios.



The problem is NOT in the mic,  it is just poor grounding of the CPU!



Any questions or comments can be sent To:



                             N3KCT


                                        73 de Mike !!



P.S.  I do not assume any responsibility for this mod, so procede only

      at your own risk and capability.