Help please. Murphy A30 volume control.

[Station X]

Does it have a three core mains lead? If it hasn't the trip won't operate even though the chassis may be live.

Have you done the resistance checks? What was the result?

[RADIO DUFF]

tested with meter readings on both l and n come to zero with switch on

[RADIO DUFF]

has three core lead but there was no earth connected on original ! should i connect earth there is a tag fastened to chassis with nothing attatched ! looks like there has never been connection to this tag

[Station X]

Originally Posted by RADIO DUFF

tested with meter readings on both l and n come to zero with switch on

I need clarification of this.

Is the reading zero ohms ie the same as you get if you touch the meter leads together?

Or is it infinite ie the same as you get when the meter leads are not touching?

If the former, stop using the set immediately.

Yes. You can connect the earth wire of the mains lead to the chassis.

[RADIO DUFF]

meter set at 2m in ohms setting reads 1 with leads not touching when testing both pins on plug reading still 1 no movement

[Station X]

That's OK then, assuming the meter is working. Confirm this by touching the leads together and checking that the reading changes to near zero.

Try the mains lead test using a lower range too.

[RADIO DUFF]

Meter does go to zero when you put both probes together! Is there any need to connect earth to chassis or can that be left? Same reading on lowest setting on meter.

[Station X]

Originally Posted by RADIO DUFF

Is there any need to connect earth to chassis or can that be left?

Depends on whom you ask. I think it's a good idea for safety reasons and I always do it. Others say it increases the strain on the mains transformer's insulation and leaves the set non-original.

[RADIO DUFF]

Thanks for your info it was a bit of a suprise to see the tester screwdriver light up ! as a novice i am very wary about doing things right dont want to cause harm or injury or death ! Just getting the set in perfect working order has been a trial ! It is very interesting working on these sets and i am amazed at how good they sound ! Am a bit wary on connecting the earth as there does seem to be conflicting ideas as to yes or no as i said there was no connection to earth on original lead and that is what is confusing me ! The main transformer is original so its from1936 and although it looks ok i dont want to ruin it as it would be a pain to replace it with a modern version if there is one that i could use !PS have cleaned up connections since the pics were taken they are much neater now