Marconiphone 271AC Radiogram


The Marconiphone 253AC is a 3-valve (plus rectifier) TRF receiver designed to operate from AC mains of 200-250 V, 50-60 C/S.
A similar chassis is employed in the Marconiphone 254 and 271 AC radiograms, in the HMV 436 and Columbia 355 AC table models, and in the Columbia 620 AC radiogram.
Release dates: Marconi phone 253, 1932; 254, 271, 1933; HMV 436, 1933; Columbia 355, 620, 1932.
(ref. Trader Service sheet 573, Wireless and Electrical Trader, June 6, 1942)  See http://www.radiomanuals.info/


As found this set was in a pretty poor condition.  The original turntable had been replaced with a cheap 1950s model and the cabinet wasn't great - though free of worm.  It wasn't felt worthwhile to restore, but dismantling it revealed that the mains transformer had been replaced with a rather more substantial type.  The speaker was in good order and all valves were present. 



Schematic

Valves

 Valve  Anode  Screen  Heater  
 V1 MS4B  230V 3.5mA  62V 0.6mA  4V 1A  
 V2 MH4  40V
1.8 mA
 -  4V 1A  
 V3 MPT4  250V
36mA
 210V 6.5mA  4V 1A  
 V4 U12  25mA DC each anode  -  4V 2.5A  
Note the valves in this set (the Marconi ones are probably original) are glass, not the metal Catkin types.

From valves

Other sets with this chassis 

Which looks identical to the HMV 435 of 1932
See the attachments to this page for a review of this set.


Ċ
Michael Saunby,
25 Jul 2009, 01:38
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