[TenTec] O-II Power Board Caps

Trevor Smith virago at wildblue.net
Sun Apr 4 07:28:51 PDT 2010


After 6 years of nearly 100% power on my O-II demonstrated the dreaded 
power board failure.
Sure enough C6 was almost 1/8" taller than the other 2 caps as it pushed 
upwards from the bottom - no leaks though.

I replaced all 3 with 85c 470uf/100v while I await the delivery of the 
N6IE recommended caps from Mouser.
They are only ~90 cents now if you buy 10. So I also took the 
opportunity to finally install the TT headphone RF filter.

Being paranoid I decided to check all the 470uf 16v that I could find 
and to my horror the 2 on the SHARC board
have nice little domes just like three mile island. C230A & C230B 
decouple the Codec chips and live next to the 2
filter inductors on the RHS of the Sharc board. A similar cap on the 
main RX board is totally flat topped.

Anyone had these fail before? or am I the only guy with ~50,000 hours on 
my O-II?  (with the electric bills to prove it!)

And a big thanks to N6IE and his webpage ( N6IE.com) for all the debug 
info there.

-Trevor AB5EU


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