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Icom Inc. 

1-1-32, Kamiminami, Hirano-ku, Osaka, 547-0003 
JAPAN 
Phone : 06 6793 5302    Fax : 06 6793 0013 
URL : http://www.icom.co.jp/

 

 

 

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Technical 

Information

 

 

To 

: ICOM Distributors

 

From 

: ICOM Inc. / Export Department 

Ref  No. : SEN-015-03 

Date 

: December 17, 2003 

 

Re. Improvement of the PA Driver for the IC-746PRO/ 7400 series. 

 

Thank you very much for your continuous strong promotion for our products in your market. 

 

The following is the information for the improvement of the PA driver for the IC-746PRO/ 7400 series. 

  

Model:

  

All versions of the IC-746PRO/ 7400 series. 

 

Symptom:

  

No RF power output. 

 

Cause: 

The driver transistor on the PA stage will be damaged when the transceiver is used in a high 

temperature environment and transmits continuously. 

 

Procedure of this improvement: 

For solution of this problem, we have reduced the current drain of the circuitry on the PA stage. 

The following is the procedures for this improvement. 

 

(1)  Replace the parts as shown in the parts list and parts location. 

(2)  Replace the MP34 screws which is fixed to the DRV board. 

(3)  Adjust PA idling current to 1.5A from 2.5A. 

 

 

 

 

 

Service handling necessary:

[  ] Yes    [X] No 

Summary of Contents for IC-746PRO

Page 1: ...the PA driver for the IC 746PRO 7400 series Model All versions of the IC 746PRO 7400 series Symptom No RF power output Cause The driver transistor on the PA stage will be damaged when the transceiver...

Page 2: ...All versions EXC ELDR25C LR 270 PA R41 7030010660 1 0 Removed 01 only 6 8 ERJ1TY None PA R41 7030010570 1 0 Removed 02 03 04 05 08 09 4 7 ERJ1TY None and 10 only PA R41 0 7030010660 1 Added All versio...

Page 3: ...1 1 32 Kamiminami Hirano ku Osaka 547 0003 JAPAN Phone 06 6793 5302 Fax 06 6793 0013 URL http www icom co jp Page 3 of 7 Parts Location on the PA board L6 L2 R41 and R42 Schematic Diagram of the PA b...

Page 4: ...2 Kamiminami Hirano ku Osaka 547 0003 JAPAN Phone 06 6793 5302 Fax 06 6793 0013 URL http www icom co jp Page 4 of 7 Parts Location on the CTRL board D25 D26 and R154 Schematic Diagram of the CTRL boar...

Page 5: ...om Inc 1 1 32 Kamiminami Hirano ku Osaka 547 0003 JAPAN Phone 06 6793 5302 Fax 06 6793 0013 URL http www icom co jp Page 5 of 7 Parts Location on the DRV board R11 Schematic Diagram of the DRV board R...

Page 6: ...i Hirano ku Osaka 547 0003 JAPAN Phone 06 6793 5302 Fax 06 6793 0013 URL http www icom co jp Page 6 of 7 Replace the MP34 screws on the CHASSIS board which is fixed to the DRV board Adjust PA Idling c...

Page 7: ...a 547 0003 JAPAN Phone 06 6793 5302 Fax 06 6793 0013 URL http www icom co jp Page 7 of 7 Updated Serial Number This modification has not yet been applied in production units However the serial number...

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