A number of you offered suggestions a couple of weeks ago and I checked those
suggestions a couple of times. I have finally got back to trying to track down
what
is probably a silly error on my part that has broken my Clipperton-L. The mods
were
triggered by the destruction of the original parasitic suppressors. The amp was
working - just not well in all conditions.
I replaced the power supply board (just an upgrade to better supply), replaced
the
plate RFC to an Ameritron AL-572 RFC along with the parasitic suppressor board,
changed the plate bypass cap at the power supply side of the plate RFC to a
0.002uf
value, changed the plate blocking cap to 0.002uf, changed the filament RFC to a
bigger unit, and changed a couple of doorknobs for 160 (unrelated to the
original
problem of the parasitic suppressors). I haven't gotten to 160 yet. The current
effort
is using 40. The current result is still no output
1. There is plate current (as measured by the panel meter) and there is plate
voltage.
2. I don't have a HV probe but I could measure at the plate voltage (at the
plate caps)
as the voltage was dropping after turning off the power switch and it tracked
with the
panel meter.
3. The idle current seems OK.
4. The plate current follows keying. The plate current changes as it should as
the driving
power is increased or decreased.
5. Adjusting the output cap controls has no noticeable effect on the plate
current (no dip
etc).
6. Using an ohmmeter there is continuity (short) from the output network side
of the plate
blocking cap (on the cap lead) to the output connector. From the other side of
the
plate blocking cap (on the cap lead) to the power supply there is continuity
(short).
Thinking perhaps the new blocking cap might be bad I replaced it with a pair of
0.001uf
in parallel but still have the same result. (I remeasured the shorts after
replacing the
blocking cap.)
7. The output relay is switching as it should. None of the wiring to the relay
was touched
in this mod.
It has been a long time since I worked on an amp. I am sure I am overlooking
something
small and silly. I was hoping one of the gurus here might have a pointer or
suggestion of
something I might have missed.
Thanks
73, Larry W6NWS
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