The following is a partial, not-to-scale, parts placement layout of the IC-820H DISPLAY UNIT circuit board (bottom view). The DISPLAY UNIT is the large circuit board that is located directly behind the front panel. Locating the following four distinctive parts will ensure you have the right diodes: the main dial encoder, the microphone compression level variable resistor (R101), J10 a ten 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.
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UHF TX --> -[ []- D28 |
CB RPT --> BLANK |
VHF TX --> -[ []- D27 ----- |
-[ []- D24 [R106] |1o | |
UHF RX --> -[ []- D26 [R107] | o | | B
-[ []- D23 [R108] | o | MIC | O
VHF RX --> -[ []- D25 [R90 ] | o | J COMP | T
NOTE 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
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Note 1: The IC-820H Service Manual calls this board the "DISPLAY unit" and the modifications call it the "logic board"; they are one and the same.
Note 2: Diode D22 is listed as "[EUR],[AUS] only" in the IC-820H Service Manual.
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