This is my first visit to this site for about 6 years as I had to put the hobby on hold to do more urgent stuff. I started to restore this tape recorder in 2010 and have today started to have another look at it. I decided I was not happy with the tiny 3 pin mains plug / socket arrangement as the terminals are very close together and there is not much to stop them from touching. Instead I will have the cable hard wired but entering through the compartment in the cabinet intended for cable storage.
I have a circuit diagram but have been tracing the wiring to the various internal plugs etc. The valve heater wires (green and brown) are not shown on the circuit diagram but just terminate with "X X" symbols. I notice that the green heater wire is connected to the chassis / mains earth, again not indicated on the circuit diagram. Is this correct or should I change it? Another minor issue is that I am getting a resistance of 3K across the On/Off switch when switched on but I suppose there are bound to be dirty contacts on something this old. It looks like this switch gave trouble before as only one of the dual poles is in use.
I have a circuit diagram but have been tracing the wiring to the various internal plugs etc. The valve heater wires (green and brown) are not shown on the circuit diagram but just terminate with "X X" symbols. I notice that the green heater wire is connected to the chassis / mains earth, again not indicated on the circuit diagram. Is this correct or should I change it? Another minor issue is that I am getting a resistance of 3K across the On/Off switch when switched on but I suppose there are bound to be dirty contacts on something this old. It looks like this switch gave trouble before as only one of the dual poles is in use.