Older RS/GRE scanner receiver measures 100vac from chassis to ground

[videobruce]

I have two similar scanners (Radio Shack Pro4004 & Pro2006 mfg by GRE) of similar design that I just discovered both have a 'hot' chassis. Measuring 100vac (no load) to earth ground (grounded roof antenna). It's a non-grounded line cord.
They both have a 'old school' power supply (metal enclosed xformer), not switching that is mounted to the metal chassis. There is a 1.8 meg resistor from the neutral to the chassis. There is no other component between the AC line cord and the xformer.

If I de-solder the resistor, the leakage voltage drops to 9vac. So the question is, is it ok to leave it disconnected? I assume the 1.8 meg resistor is to drain any static charges off the chassis .

The odd thing is I have had one of these for probably 30+ years and never noticed this which I did now by re-connecting the antenna cable and holding a external metal enclosed FM broadcast filter and the antenna cable connector.

 

[a417]

<snip> It's a non-grounded line cord.
They both have a 'old school' power supply (metal enclosed xformer), not switching that is mounted to the metal chassis. There is a 1.8 meg resistor from the neutral to the chassis. There is no other component between the AC line cord and the xformer.

Can you turn the plug around in the socket, is it non-polarized? Many older tube radios (like the all-american 5s, IIRC) with a non-polarized line plug also do this.

 

[prcguy]

I would measure the current from chassis to your earth ground. It could be leakage through the 1.8meg ohm resistor and that would be harmless at about .00007A and very hard to measure. If its more than that then I would suspect an AC bypass capacitor has gone bad.

 

[videobruce]

The line cords both having quick connects by the radios had the L/N swapped. I didn't see it the 1st time.