[AMRadio] Winter

[rbethman]

  Todd,

I believe the same sort of issues had developed in the BC-610 family.

They went from either 866s, (or 872s) to 3B28s.

They additionally did away with the ceramic output insulators and went 
with the SO-239.

With this done, they are quite hardy beasts!  The only caveat is to keep 
the rotating link movable, W/O leaving "to" much De-Oxit on the joints.  
If you do, you'll get a flame-over on the PA coil!  (Don't ask!).

Bob - N0DGN

On 10/1/2010 12:22 PM, Todd, KA1KAQ wrote:
> <SNIP>
> Yep, that was the main problem with the transmitter when I first got
> it on the air. MV flash overs galore. Put in new 872s and before long,
> the same issue. Switched to the 4B32s about ten years back while off
> the air (was working on the rig into a dummy load) and those flash
> over issues disappeared.
>
> I *think* I found source of problems in the tank circuit, and it's not
> at all something you'd expect. There are some indications that there
> has been an intermittent HV issue with the rig for many years, from
> notes in the manual and such. I'll post photos of it on 'fone later
> once it's all done, but suffice it to say it involves a feed thru
> insulator handling HV breaking down to ground in a way I've never seen
> before, and never thought possible. Others with this transmitter have
> had similar problems, but the particular failure mode really surprised
> me.
>
> Though it looks like the culprit, I won't know for sure until it's
> reassembled and back on the air to test. Need to see if I can dress
> the plates on the loading cap under the deck with some crocus cloth
> before buttoning it up. Too much of a bear to remove this one, but
> fortunately I can only see a few tiny bright marks on the edges that
> look like they were caused by arcing.
>
> Heard you on last night Don down on 05, was reinstalling the loading
> cap and listening. You'd left by the time I finished up at 1:45AM.
> Think I invented some new swear words trying to get one of those
> silver straps from the band switch reattached to the side of the air
> variable.
>
> ~ Todd/KAQ