TYT TH-9800 repair

TYT TH-9800 PA failure ... no power output and i found this by using my oscilloscope to trace the RF from the driver fet to the output fet and found a pin diode that had got so hot it had desoldered itself from the pcb... possible pin diode failure even though it was reading ok on my diode test... This could be down to parasitic oscillations in the pi network on the PA stage... please note this was not a permanent repair as the pin diode was still getting hot so this radio still has issues and is being used as a receiver only at this time ...

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