Philco Model 255

 This radio arrived for a refurb back in 2002 but the owner hadn't realised it was a battery model so agreed to a swap. It was made in 1935 and bridges the gap between battery operated TRF sets and the superhet. It has an IF of 451Kc/s which is higher than its earlier cousins. It has both medium and long waves.

 

 There are 4 valves. One is hidden in the square can with the lead disappearing into its top. The original valves were all US made by Philco so may have caused a few hackles to rise in the British Radio Manufacturers' protectionist mob. The frequency changer was a 1C6 (UX6), the IF amp 1A4E (UX4), audio amp/det/AVC is a 2102 (UX6) and the output valve the unusual twin pentode 2103 (UX7). All are on the American UX base. At some time in the distant past a service chap fitted a UK valve in place of the frequency changer. He fitted a Mullard FC2A and made an adaptor to line up the B7 base to the original UX6 socket. Perhaps he used the UX base from the old 1C6? The FC2A is pretty obvious as it now sits a couple of inches higher due to the size of the adaptor. The loudspeaker is of course a permanent magnet type because the set is not mains powered.
 

 
 

 Above, the tiny dial which is common amongst American sets of this period.

Right, the Mr Marconi stealth tax notice and below a note that echoes that attached to modern washing machines. Maybe the precaution of tightening the chassis was to deal with shipping from the USA?

Bottom right is the code of the tuning condenser. Philco had a regime, similar to that used later during WW2 by the UK military. Every single part had a special code, so the Philco Radio Service Bulletin had a listing which has "Two Gang Condenser and Trimmers... 31-1566" and finally the serial number stamped on the chassis. Unfortunately the identification paper inside the case has been torn off.

 

   
 
 

 Below, the Model 255 circuit diagram.
 

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