Well, I got my problem figured out. I opened up the unit to replace the
fuse and to see if there were any problems I could see. I examined the
step-start relay (an open frame type), and tried to move the contact arm.
That's when I noticed that the arm was "misaligned". I obviously had
bumped it when I was replacing the detector diodes. Anyway, it was a
simple matter to wiggle the arm back into place. I put the lid on with a
single screw to test things, and everything seems to be fine. It is all
buttoned up now,,and is working fine.
Thanks again for the replies; I just wanted to let everyone know what was
found.
73,
John, K8DIL
On Fri, Nov 28, 2014 at 2:48 PM, John DiLorenzo <john.dilorenzo33@gmail.com>
wrote:
> I acquired this amplifier about two weeks ago, and when I received it,
> neither theforward nor reflected power meters would indicate anything. As a
> "test", Ireplaced the detector diodes (D114 and D115) with 1N914s as these
> were diodes I had on hand. My intent was to see if the meters would at
> least register something, and if so, order the correct diodes (1N34s).
> Well that worked,so I ordered the diodes.
>
> They arrived, so I replaced the 1N914s with the correct 1N34s. With the
> unit all buttoned up again, I noticed while tuning up, the meter lamps
> would dim, and the HV would sag significantly. I wanted to test and record
> some values when the amp shut down completely; this is what I had to that
> point:
>
> HV
> (volts) Ig
> (mA) Ip
> (mA) Standby 3050 0 0 Keyed, no drive 3050 0 0 CW, 5W drive 2700 20 125
> I discovered that F101 had blown in the amp. This fuse is in series with
> the step start resistor, so it seems my step-start was staying in the "low
> current" mode, and when I keyed the amplifier, this 2A fuse blew as
> expected. I'm just not sure what broke. The diodes I replaced aren't near
> the rectifying diodes that pull the step-start relay. Any insight into
> common failures, where to start looking, or how to debug?
>
> Thanks in advance,
> John, K8DIL
>
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