home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Libris Britannia 4
/
science library(b).zip
/
science library(b)
/
HAM_RAD
/
3176.ZIP
/
ICOM2.ZIP
/
IC765
< prev
next >
Wrap
Text File
|
1990-10-14
|
2KB
|
67 lines
Model: IC-765 Revised 11-10-89
Division: Amateur
Note: This service bulletin is meant for technical per-
sonnel with experience working on solid state com-
munications equipment. Damage caused by im-
properly installing this modification may cause
ICOM to charge for subsequent repairs to the
product. ICOM does not warrant this modification.
Bulletin #: 26989R1
Date: September 26, 1989
Subject: The antenna tuner on some IC-765s "hunts" during
transmit after the first tuning phase is complete.
This may start after a few months of use.
Information: The feedback circuit that controls the tuning
motors may become sensitive after a few months of
use.
Procedure
1. Remove the top cover and locate the antenna tuner board.
2. Locate R5 and R10 and set them to the center of their range.
3. Set the following controls on the radio as indicated below:
Tuner - On
Frequency - 7.1 MHz
Mode - LSB
4. Transmit for 10 seconds.
5. Verify V-ref at R4 is between 4.6 and 5.3 VDC.
6. Adjust R5 for a voltage that is one half of what was
measured in step 5 +/- 0.1 VDC measured at R2.
7. Adjust R10 for a voltage that is one half of what was
measured in step 5 +\- 0.1 VDC measured at R7.
8. Verify proper tuner operation on all bands.
9. Reinstall the covers and return the radio to operation.