Modifications for the ICOM - RogerK

Add a diode on the blank position between D27 & D28 on the Logic Board. The part is 1SS353 P/N 1750000390.After hardware modification1. Set lock mode. Push [LOCK]2. Turn Power off.3. Hold [M/S] and turn radio on.4. Turn repeater off. Push [LOCK].Note: If you removed Diode D25 or Diode D26 in the first modification then it can be used in the second modification as it is thesame part.This modification is read 698 times.top of page23-11-2001(IC-820) IC-820H display boardThe following is a partial, not-to-scale, parts placement layout of the IC-820H DISPLAY UNIT circuit board (bottom view). TheDISPLAY UNIT is the large circuit board that is located directly behind the front panel. Locating the following four distinctive partswill ensure you have the right diodes: the main dial encoder, the microphone compression level variable resistor (R101), J10 aten pin header and a row of surface mount resistors immediately above J10.CAUTION: These diodes are NOT labelled sequential! Ensure you are certain of which diode you wish to remove.|||UHF TX --> -[ []- D28 |CB RPT --> BLANK |VHF TX --> -[ []- D27 ----- |-[ []- D24 [R106] |1o | |UHF RX --> -[ []- D26 [R107] | o | | B-[ []- D23 [R108] | o | MIC | OVHF RX --> -[ []- D25 [R90 ] | o | J COMP | TNOTE 2 --> -[ []- D22 [R91 ] | o | 1 ------ | T[R92 ] | o | 0 | | | O[R93 ] | o | | R101 []- | M[R94 ] | o | | | |[R95 ] | o | ------ || o | | E----- | D| G| E/-------------------------------------| |/ | |/ | | O/ | | F/ | || E N C O D E R | || | | C| O P E N I N G | | A| | R| | D| || |-------------------------------------| ||Note 1: The IC-820H Service Manual calls this board the "DISPLAY unit" and the modifications call it the "logic board"; they areone and the same.Note 2: Diode D22 is listed as "[EUR],[AUS] only" in the IC-820H Service Manual.This modification is read 703 times.top of page