I am second owner. This one covers 160-10M
6 yrs ago had problem on 12/10M, possible parasitic, blew 25 ohm res in B-
and plate choke. Henry said there was a mod for this problem. Deck was sent
back to Henry and they put in a set of contacts which short part of the
plate roller inductor, on 15 - 10M. connected to the 15-10 band switch cam.
This shorts out the 160 end of the coil on 15-10M. ( 15 t or about half of
it) I didn't really understand what this accomplished, but trusted their
design change.
So the problem still is there. I usually use it only on 160M, but needed it
on 20M the other day and got that big "bamb" tuning it up, only at about
1000w or so. It trips the breaker, 40A.
Plate choke is blown, two black marks on the plate choke, about 1.5 and 2.5
inches from the bottom. Also there appears to be some arcing from on the
band selector contact, 160M, which is on the end, to a screw, grounded,
which holds the band switching contacts plate. Henry didn't use a rotary
switch, just a flat board which holds contacts activated by cams .
I was going to use an AL1200 plate choke, but its too big.
Henry didn't use any type of neutralizing on the 1200A7, which is suspect
might be part of the problem. I also suspect the rather long leads on the
parasitic plate suppressor. A good 2 to 3 inches could be taken out and
still make connection.
Has anyone been down this path before?
73 Jack N8DX
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