As a wild guess (have not been there/done that), the inductance of the
suppressor is too high. There will be a voltage drop across that inductance
related to the current through it. If this voltage is high enough, the 100 ohm
resistor will be above rated dissipation.
The power dissipated in the resistor is equal to the voltage squared
divided by the resistance.
If the suppressor was designed for 10m, it is not surprising that the
inductive reactance is greater on 6m resulting in more dissipation in the
resistor.
You can reduce the inductance (fewer turns) or increase the power
dissipation of the resistor.
The 3CX800 is a quite high frequency tube with short internal leads. You
may find that the suppressor is not even needed. Again, beware: I have been
there/done that. Use caution.
73,
Gerald K5GW
In a message dated 9/9/2009 2:30:14 P.M. Central Daylight Time,
K8LEEWMM@aol.com writes:
gentlemen
I have acquired a nice 76ca that has been converted to a pair of 3cx800,s
.
The challenge now is that it also has been converted to 50mhz.
On my first testing done, it worked very good. After running some test I
slowing loaded
the amp up for near max output. Within about 2 minutes the original plate
lead suppressor went
up in smoke. The 100ohm resisters opened.
I have talked too and tried some of ag6k,s fix,s but no real steps
forward.
I have tried parasitic suppressors from a Drake L4B , the single "U"
type
with no change.
It does have a tuned grid input unit mounted on the back, to me it seems
to
tune much too sharp?
The plate choke looks non original, issue there?
thanks for ur thoughts
wayne k8lee
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