[Amps] Plate Choke Issue

[Victor Rosenthal 4X6GP]

Did you check for resonance with a GDO with the choke shorted? You need 
to do this with it in place.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/
On 3 Jan 2018 17:28, AJ wrote:
> 
> Hi people.
> 
> I have some sort of issue I have not been able to figure out or do not
> understand the issue. I checked the bypass values the relay the wires
> etc.
> 
> Ok here's the skinny, multi-band amp. Works fine on 160,80,40.
> It was fine on all bands at one time; do not know what happens on 15 or
> 10 at this time. Tune the amp for ~2200 on 20 meters all is fine; get up
> to 2600 obviously into the load. And kerbang! ! ! Blows the ceramic and
> high voltage arc to some part of the chassis and a corona burn off of
> the wire.
> 
> Get a new ceramic insulator ( .75 x 4") as large as there is room.
> Wind 25 awg wire and ~65 cs turns on it. Fasten the ends to machine
> cir-clips. Measure inductance in the amp mounted 31.8 uh. Looked for
> any series, checked for heating with 2 amps of current etc. Checked the
> relay for function.
> 
> Well it lasted about 3 months, kerbang ! ! wife was in the room when it
> happen. muwahahaha actually it really was not funny, 3650 vdc at the
> choke, ~1 inch to any part.
> 
> So I dropped the number of turns now 27 uh, well that lasted about a
> week, not sure how many tx's; again on 20 meters.
> 
> This time I was able to measure where it blew apart, ~20 uh from end to
> end. I slid the wire off the broken ceramic and slid it onto a new one
> mounted it in the amp to measure. I am referring to RFC-1
> 
> pic is here http://oi67.tinypic.com/2lwmb5u.jpg
> 
> What am I missing?
> 
> 
> AJ___ VE3HJ