MS Marshall Clark / 6ZKA
Fotos (2) und Bericht © 2009: Ragnar Sivertsen

By courtesy of: Ragnar Sivertsen Radio Station MS Marshall Clark / 6ZKA
Marconi Crusader Radio console, all units were generally very good and trouble free -- except the Tx power supply unit located in the desk just underneath the Crusader Tx, and therefore not visible in my photo. The Tx, with it's external power unit was brand new construction. This power supply unit was a nightmare on all three sister ships, with bad quality transformer insulation and a special Marconi 600-volt rectifier tubes which wore out extremely fast --  my first 3 weeks onboard wore out 2 dozen spare 600-V
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 LifeguardSignal 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.
By courtesy of: Ragnar Sivertsen
MS Marshall Clark / 6ZKA in rough sea  The 80.000 tdw OBO-carrier under Liberia flag, built Japan 1965 for Berge Sigval Bergesen, Oslo, but later taken over by his father, Sig. Bergesen d.y, Oslo. I onboard 1965-1966. Carried iron ore from Lourenco Marques, Mozambique to Japan on long time charter. I was also on the sister ship Inayama 1968-69.

Alle Fotos (2)  Urheber gem. §7 Urh.G. / © + By courtesy of: Ragnar Sivertsen, N (Mit freundl. Genehmigung 2009)
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Version: 18-Nov-09 / Rev.: 22-May-11 / HBu