Mods for IC-821HTX/RX136 - 174 Mhz 420 - 460 Mhz plus Tone Mod
You do this at your own Risk!
Mods for IC-821HTX/RX136 - 174 Mhz 420 - 460 Mhz
1. Remove power and antenna.
2. Remove screws and open case.
3. Locate display board.
4. Locate and remove Diode D101. (144 RX Modification)
5. Locate and remove Diode D103. (440 RX Modification)
6. Locate and remove Diode D105. (144 TX Modification)
7. Locate and remove Diode D107. (440 TX Modification)
8. Locate and install Diode P1F. (1SS355 – X-Band repeater Modification)
On this page is the x-band (cross band) repeater mod described for the ICOM IC-821h alamode dual band transceiver with photo'sI have not done this mod myself (yet) the schematics come from ICOM Europe and the mod has been tested by Wolfgang DJ9JY.You need to locate the row of diodes on the display board, for that You need to remove top and bottom covers of the 821 (described in Your owners manual on page 50 and remove two screws witch hold the front of the 821 and turn the 2 other screws 1/4 loose so You can pull the front towards You (about 5cm)Now You have to solder a diode in to the space reserved for D108.(1ss355) You can use one of the diodes you have removed (d101-d107)As far as I know D108 is never in place as it leaves the factory.If this is Your first attempt to solder anything I would suggest to leave it until You have a lot of practiceIn this drawing You see were D108 should be placed