Hello Roger and group,
I had the same problem with an L-7 I bought some time ago. It came
without P/S, was cheap and had 3-500ZG with graphite anodes from RF
Parts. But I was aware of a short in the load cap because you could hear
it when turning even without RF applied. I bought the whole thing anyway.
To fix the problem, I had to get the cap out of the L-7. That is not the
nicest job you can imagine but can be done. There was some melted
aluminum on 2 plates. I used a Dremel with a sanding disc to get between
the plates and sand out the aluminum. Luckily the short was not further
inside. I would have had a hard time if this had been the case.
The cap can be aligned so that the plates are centered. Maybe yours has
been mistreated by a previous owner.
73s Dieter DL5RDO
Am 30.07.2012 03:53, schrieb Roger White:
I have had a Drake L-7 sitting on the shelf unused for a few years now
and recently decided to sell it. It has had the power supply updated
and the ON/OFF switch disassembled and cleaned. It had functioned OK
the last time I had used it (2 years ago) with the only problem being
an erratic reading Plate Amp meter (an quick tap on the meter made it
come from "zero" to the correct reading).
The problem I am having now (and one that has never occurred before)
is the Load Variable Capacitor is appearing to short some of its
plates over a narrow arc of operation (say 10-20 degrees of arc). I
can hear the plates touching and, of course, the resultant negative
effect of the power out going to zero, etc. I have only had the amp
open once to clean the power switch, I could tell it may have been
worked, on as far as the screws on the bottom cover(s) appear to have
been removed at few times.
One thing I have noticed as I looked at the cap with the cover removed
is that I can hear the plates "unshort" if I "torque" the chassis a
little bit or loosen the screw that holds the front half of the Load
Cap to the floor. Has anyone had this sort of problem with one of the
variable caps? Can the Load var. cap be removed easily?
Thanks for any help in advance.
Roger White W5RDW
Murphy, Texas
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