28-07-2016, 09:09 AM
(This post was last modified: 28-07-2016, 09:12 AM by Old Sparky.)
As I understand it, and I've been repairing electronic items for 45 years now, a three core mains lead should never be used in any apparatus using 'U' series valves (i.e. sets commonly referred to as 'live chassis' models) It's also important to ensure that the Neutral side of the mains is connected to the common negative line (usually the amplifier metalwork) in circuits such as the two shown. The isolating capacitors shown in those circuits should be replaced with 'Y' types, as Nick says. If the mains lead is the old twin 'bell wire' type, it should be replaced with a modern double insulated type. (BTW, despite what I've just said about never using a 3-core mains lead I've just noticed tha both those circuits show that such a lead is fitted, with the earth lead connected to the record deck metalwork.