[Johnson] 866A catastrophic failures?

[Charles Ring, W3NU]

kwylow zinjanthropus wrote:

> Can anyone cite any catastrophic failures that occur with equipment using 866A's (merc vap recs) that's a direct result of the same? Just wanted to know as I'm looking to retrofit a Courier with a pair of these jewels. Let me know and thanks. Cal. N6KYR
>

I guess my experience has been different from some. I have not had a plate transformer fail when a MV rectifier arcs over, but I have had the 866A filament winding on the power transformer of a Valiant short to ground. The fix was a separate filament
transformer mounted to the back side of the front panel. When that also failed years later I went to SS rectifiers on that Valiant. Peak inverse voltage is the killer of filament transformers with MV rectifiers.

On several 1KW broadcast transmitters I have seen 866A's and 8008's arc over with no harm to other components.

73 de W3NU