rectifier
tubes, 6 of them required in a 3-phase voltage-doubling circuit!. Marconi
UK ran out of stock! First call Japan I replaced them with silicon diodes
on my own initiative as the local representative couldnt get Marconi aproval
in time for departure, a warranty case.
At least two of the 3 sisterships had the big high voltage transformer
short a winding to ground with a bang! On Marshall Clark also one of the
4 filament transformers for the HV 3-phase voltage doubling rectifirer
tubes shorted out, the HV (5kV?) rectifier tubes behaved normally. In my
cases I was very lucky as I could locate the shorted secondary star winding
and cut it out, also I could disconnect the broken filament transformer
without much ill effects, just about 1 kV HV drop key down, worked okay
for a total of about 3 months before getting spares... After my time
on the Marshall Clark and sistership MS Inayama, I heard that Marconi had
replaced these bad power supply units on all sisterships on warranty, and
they worked well....
The new Crusader MFHF Tx (Left bay), 1400 Watt
SSB xtal control, performed very well, especially on SSB duplex, and for
me problem free. Consol: Central bay: Above the Atalanta
Rx is a Racal RA-17 (or 17L?) HF Rx, with it's
RA-63 SSB-adapter right above. The RA-17 was very good on CW, and with
a very good dial. AM was not a bit better than the simple Atalanta, and
it was not built for SSB. SSB with the RA-63 was no good at all,
as it was almost impossible to get a clean voice despite a good fine-tune
control on RA-63, same on MS Inayama. I suspect there was signal overload
somewhere in the myriad of tubes involved? Top unit on this bay is the
Tx antenna selector. The right-hand bay is for the 24-volt units: Bottom
charging panel, Autoalarm Lifeguard, Signal
keyer & 500 kHz spot frq Emy Rx, Emy Tx Salvor
II, all well-proven quality Marconi. On the desk is my ever-present
Vibroplex bought in Port Arthur Texas in 1954. |
