Modifications for the ICOM - RogerK

●●●●●●●●There's a shielded PCB that these leads run to. Carefully pry this up. It will then fold down. There's several flexable leads atthe bottom.You should see the CPU now.With the manual, locate where D113, D119, Q131 are.Where the new|diode goes is not marked in the diagram of the CPU PCB. Locate the anodes of D119. This land connects topin 27 of the CPU chip ic101. Locate the cathode of D113. This land connects to pin 20 of the CPU chip. These diodes areSMDs, and do not look like what you'd expect diodes to look like.In the area between Q131, D119, D113, and the CPU chip, you should see a set of 3 solder pads that form a trianglularpattern that would accept a 3 legged SMD, like the neighboring diodes and transistors. one of these pads connects to theanodes of D119. The new diode's anode goes to this pad. Another pad connects to the cathode of D113. The cathode of thenew diode goes here. This means that the new diode athode will connect to pin 20 of the CPU, and that the anode willconnect 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 shortto something. Also, take anti-static precautions. I used a bit of double-sticky-foam tape to hold the diode in place when Isoldered 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 youpried 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 dothis. The xmit power will be lower on the higher freqs.Disclaimers: Be sure to have the proper permits for out of band operations. And, do this mod at your own risk!This modification is read 424 times.top of page08-01-2002(IC-V8) IC-V8 MOD for expanded RX/TX range. (136 – 174MHz)Author: Scott KD4CWB - kd4cwb@aol.com.MODIFICATION.NET1. Remove the battery pack.2. Peel off the black plastic panel on the bottom. (it will re-stick in place).3. With the white expansion connector on your left side, locate the series of diodes in the upper right side of the opening.Remove the diode located on the far left side on the lower row. (see photo or text diagram).------------------------------------------------------_--------_-------_-----| |o| o |o| o |o| || | | | | | | || Option Connector |o| o |o| o |o| || ____ - - - || | ^ || | - - | | || | - - | Remove this | || | - - | diode ONLY! | || | - - | --------------+ || | - - | || | - - | || | - - | || | - - | || | - - | || | - - | || |____/ || |-----------------------------------------------------------------------------Mod by: Scott KD4CWB@AOL.COM