[Kenwood] TS-950SD Final Bias

[Chris Allingham]

I was operating on 10m a couple of days ago when the power suddenly dropped 
from 100W to 10W to 0W.  I soon smelled something burning and unplugged the 
rig.  I opened up the rig and found the source of the smell:  the 1K trim 
pot (VR2) in the final bias circuit of the final unit had been burnt.

Anyone know what would have caused this?  Would the trim pot have been the 
source of the problem or just the weakest link?  I know it would be 
impossible to tell without getting your hands inside the rig, but would any 
of the other components in the final bias circuit need to be replaced as 
well (Q7, R22, D3, C20, C22)?

I'm going to send the rig to a service shop for repair, but don't want them 
to replace just the trim pot and have it go up in smoke again.  Knowing 
what the cause of the problem is will also give me a better idea of how 
much the repair will cost.

Thanks in advance for you help.

73,

Chris VE3FU / VO2AC
ve3fu @ rac.ca
vo2ac @ rac.ca