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TUCoPS :: Radio :: icu2at_1.txt

Icom IC-u2AT mods




ICU2AT.1 
>In the area between Q131, D119, D113, and the CPU chip, you should see
a set of 3 solder pads that form a trianglular pattern that would accept a 3
legged SMD, like the neighboring diodes and transistors.  One of these pads
connects to the anodes of D119.  The new diode's anode goes to this pad.
Another pad connects to the cathode of D113.  The cathode of the new diode
goes here.  This means that the new diode cathode will connect to pin 20 of
the CPU, and that the anode will connect to  pin 27 of the CPU.
>Carefully prepare the diode leads to line up with the proper pads, and take
care that when you solder it on, you don't short to something.  Also, take
anti-static precautions.  I used a bit of double-sticky-foam tape to hold the
diode in place when I soldered it.  And I left the tape to help keep it in
place after I was done.  Be sure that you will be able to replace the PCB you
pried up, without it touching the diode.
>Reassemble the rig.
>Do a CPU reset.  That is: Turn the power on while holding the light switch
down.
>You should be able to xmit between 139 to about 160 Mhz.  You could tweak the
PLL to extend it further, but I didn't do this.  The xmit power will be lower
on the higher freqs.  
Disclaimers:  Be sure to have the proper permits for out of band operations.
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