How to replace old power cord with polarized cord for 1955 Zenith T825

[TomJr.]

Hi --I'm new to this forum and am a newbie to antique radio repair. I've read several articles on replacing old non-polarized power cords with polarized cords (2 blade type). What's the best way to determine where to hook up the wider side of the polarized plug on this radio?

Thanks!

 

[Gryd3]

Non-polarized plugs can be plugged in either way. I don't think it makes a difference which way you wire a polarized replacement in.

Just don't wire a non-polarized plug onto a device that had or requires a polarized plug.

 

[KrisBlueNZ]

Hi Tom and welcom to Electronics Point

I think you would be better off joining a forum specifically about antique radios. Electronics Point is oriented towards general modern electronics subjects. We do have some more senior people here, but I don't think they're into antique radios. They will correct me if I'm wrong

The basic answer is, as Gryd3 said, if it had a non-polarised plug originally, then you should be able to wire a polarised plug either way around without causing a hazard. But there are usually ifs and buts, and it's best to ask people who are familiar with the make and model you're working with.

 

[pebe]

From the link http://www.radiomuseum.org/r/zenith_t825_t_825_ch8t01_8_t_01.html

I found the spec on this receiver. It had 8 tubes with 300mA heaters totalling 114V, and a selenium rectifier.

The power supply was specified as 117VAC, so the heaters would have been connected in series directly from the supply, with no line cord voltage dropper. The chassis would have been connected to the neutral of the supply, and the rectifier and ‘live’ end of the heater chain would have been connected to the live 117V phase.

There are two antenna terminals on the back marked G and AT(?), and these are almost certainly isolated from the supply cable. But to avoid any risk of electric shock, ensure that the wire in the supply cord that connects to the chassis is the wire that connects to neutral of the plug.