Labels:book | reckoner OCR: KENWOOD SB -990 SERVICE BULLETIN Amateur Radio Division SUBJECT DATE Final Amplifier Bias Circuit Change January 23 1992 It is possible to exceed the maximum Vebo rating of the MRF429 transistors used in the TS 950S SD if the unit operated at excessive transmit power levels (greater than the normal factory output power setting.) This results in a collector to base short on the MRF-429 This causes excessive current to be drawn thru R17 and or R18 of the final bias circuit This can cause large amount of smoke from the overloaded resistors. It does not normally cause damage to surrounding components (You might wish to chect Q7 VR2 08 and the fuse just precaution!) R17 and R18 are carbon type resistors (27 ohms 1/2 w) Carbon resistors can emit quite bit of smoke when overloaded in this manner ...
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