Symptom:
If the final amplifier is operated at excessive transmit levels (over 150 watts output) the final FET's may fail and short from Source to Gate. If this occurs, the bias resistors used in this circuit may be damaged and cause a large amount of smoke to be emitted from the final compartment.
Corrective Action:
Change the carbon type resistor used for R17 and R18 to the fuse type resistors specified below. This will prevent an unpleasant odor and smoke from the final compartment.
Parts required:
Qty Description New Part No. Circuit Description
2 100 ohm ½ watt fuse resistors R92-1310-05 R17, R18
Procedure:
Remove the old resistors from their locations an the circuit board and install the new resistors directly between the Gate and Source of the final transistors. (see the illustration below).
Caution: This modification requires soldering equipment rated for CMOS type circuits. It also requires familiarity with surface mount soldering techniques. If you do not have the proper equipment or knowledge do not attempt this modification yourself. Seek qualified assistance from your closest Kenwood Service Center (Long Beach, CA, or Virginia Beach, VA).
Time required for this modification is 60 minutes or less.
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