UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - DC Mains on Pre-War TV's

Niechcial,Steve · 10th Apr 2021, 5:48 pm

Recently I came across a fascinating item for sale on Ebay. It was a service manual for a power converter unit for Philips TV sets enabling use on DC mains and it is dated 1936. It wasn't expensive so I bought it.
It basically describes a vibrator system feeding a full wave double-wound transformer. The input voltage goes from 110v to 245v. Unfortunately, the manual doesn't give an output voltage. However, whatever the output voltage is, it is not 'standard' AC mains because the TV set itself has to be the 'universal model' i.e one fitted with a different mains transformer. 'Standard' models could be converted to 'Universal' by changing their mains transformers.
There was a lot of DC mains around in London in 1936. All TVs of course had mains transformers so I guess other manufacturers had similar provision. Does anyone know anything about this? Also intriguingly, this service manual starts out ' Instead of the former method of construction of Universal Receivers, use is now made of a vibrator and transformer'. What could the 'former method' possibly be?

10th Apr 2021, 5:48 pm	#1
Niechcial,Steve Hexode Join Date: Jan 2007 Location: Beckenham, London, UK. Posts: 373	DC Mains on Pre-War TV's Recently I came across a fascinating item for sale on Ebay. It was a service manual for a power converter unit for Philips TV sets enabling use on DC mains and it is dated 1936. It wasn't expensive so I bought it. It basically describes a vibrator system feeding a full wave double-wound transformer. The input voltage goes from 110v to 245v. Unfortunately, the manual doesn't give an output voltage. However, whatever the output voltage is, it is not 'standard' AC mains because the TV set itself has to be the 'universal model' i.e one fitted with a different mains transformer. 'Standard' models could be converted to 'Universal' by changing their mains transformers. There was a lot of DC mains around in London in 1936. All TVs of course had mains transformers so I guess other manufacturers had similar provision. Does anyone know anything about this? Also intriguingly, this service manual starts out ' Instead of the former method of construction of Universal Receivers, use is now made of a vibrator and transformer'. What could the 'former method' possibly be?