jgilk1
Member
I have a cheap 10 meter amp that uses trw PT9803: RF POWER TRANSISTOR : NPN SILICON 36V IC=15A PO=60W 14-30MHZ :: RF POWER SOT-123 PACKAGE (single stud not 2 hole flange)
Be it high swr due to a fault coax or over driving at 3.5 watts dk at 70% modulation at 14.2 volts either way it took out part of the bias circuit...
Any ways I would like to rebuild it vs replace it... Since the pt9803 is long since no longer available I have been looking for replacement the mrf455a would be a near identical replacement they are worth more then the amp and not so commonly available any more...
I have found a replacement for the mrf455 is the sd1446 flange transistor... But I an guessing that there will need to be a bias change to go with it....
Any clue what changes I would need to make to bias to get these to work or can I solder they directly in and drill/tap the heat sink for the flange vs stud???
Be it high swr due to a fault coax or over driving at 3.5 watts dk at 70% modulation at 14.2 volts either way it took out part of the bias circuit...
Any ways I would like to rebuild it vs replace it... Since the pt9803 is long since no longer available I have been looking for replacement the mrf455a would be a near identical replacement they are worth more then the amp and not so commonly available any more...
I have found a replacement for the mrf455 is the sd1446 flange transistor... But I an guessing that there will need to be a bias change to go with it....
Any clue what changes I would need to make to bias to get these to work or can I solder they directly in and drill/tap the heat sink for the flange vs stud???
