Quote:
Originally Posted by Brigham
Is the Dual-Standard switch still fitted?
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Hi Colin, There is no evidence of any components in the timebase chassis ever been fitted for the 240/25 Baird system.
In 1947 the receiver was returned to the works for a complete overhaul. New electrolytic capacitors fitted and a number of modifications carried out to improve reliability. For example, 50 ohm resistors fitted between the anodes of the IW4-350 HT rectifiers and the secondary of the mains transformer. The replacement electrolytic capacitors are of TMC make, dated 1947.
The 2.5volt CRT filament is suppled from a separate winding on the mains transformer. In series with the CRT filament is a variable resistor. This component has gone high value so the CRT filament was underrun.
The attachment shows the timebase and receiver units have been successfully removed from the cabinet. The wooden shelf is close to disintegration, another part to replicate.
DFWB.