Kenwood mini-stereo model:KR-595 shuts off
 

Kenwood mini-stereo model:KR-595,year:Jan 1996,unit shuts off when
power button is pressed,here is history:

Aug 7,2004:
Replaced right channel:
Q18=2SD2222=NPN=shorted
Q20=2SB1470=PNP=shorted
F13=5 amp power supply fuse=open

Feb 18,2005:
Replaced:
Q20=2SB1470=PNP (again) (different supplier)=base to emitter open

July 19,2005:
Replaced:
Q20=2SB1470=PNP (again another different supplier)=base to emitter open

And now Aug 16,2006:
Q20=2SB1470=PNP=base to emitter open

Before I replace Q20 again WHY IS IT FAILING SO MUCH?.

Thanks in advance.

Sidney
E-mail:sidneybek(at)yahoo.com
Dartmouth,Nova Scotia
Canada