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January 9th 04, 06:32 PM

On Fri, 9 Jan 2004 16:49:57 UTC, (geojunkie) wrote:

I have restored several receivers, but this is my first transmitter.
It seems to be nearly 100% original... paper caps and all. It was
reported to have been regularly used up until last summer by the
previous 30 year owner. I assume that I should go ahead and replace
the paper caps, check the resistors, and check/replace the
electrolytics as I have been for receivers... correct me if I am
wrong. Is there anything else that usually needs to be done/inspected
for a transmitter? I have no way of testing the 4-400 outputs or the
3B28 rectifiers, so do I just fire it up and hope for the best? I
assume I should try and bring this up with a variac, but would really
appreciate a startup procedure recommendation for high power vintage
transmitters.

What a beast. Lifting the power supply will make your eyes water. This
has the largest transformer and tubes I have run across to date. Can't
wait to see what those 4-400s look like lit up.

Dan

After you replace the caps and bring the voltage up slowly with a
variac, you still shouldn't transmit unless you have a known good,
known low-SWR antenna.

Having an antenna or even better, a Heath cantenna, you can tell if
it is transmitting with a power meter and your receiver. The
receiver will tell you the frequency and a power meter will show you
that the controls are working properly, load, tune, drive, etc.

That much power will quickly warm up a cantenna.

Parasitics are self oscillating finals. If that happens, the plates
of the tubes will glow red when you apply HV but are not talking
into the mike or are key-up. Watch for this and be ready to cut
the power.

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