[TenTec] O-II Power Board Caps

[Ron Castro]

Trevor:  Thanks for the nice comments about my site...it's good to know it's 
doing some good out there!

It would not surprise me that there are other electrolytics in the radio 
that may fail given enough time, especially since all electrolytic caps will 
eventually die, and those in circuits that cause them to dissipate more heat 
are likely to fail sooner.  I also still believe that TT got a shipment of 
'sick' capacitors like the ones in this Wikipedia article I have referred to 
many times:

http://en.wikipedia.org/wiki/Capacitor_plague

The good news is that after all the hours you have run your radio, those 
other caps haven't caused it to malfunction...yet!  The average active ham 
uses their radio maybe 2,000 hours per year, so your radio might be the 
equivalent of 25 years of service.  BTW, after about 5,000 hours since I did 
the fix on the A9 board in my OII the new caps still look perfect with no 
failures.

            Ron  N6IE
       www.N6IE.com

----- Original Message ----- 
From: "Trevor Smith" <virago at wildblue.net>
To: <tentec at contesting.com>
Sent: Sunday, April 04, 2010 7:28 AM
Subject: [TenTec] O-II Power Board Caps


> 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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