Electronic Creations Co. one tube wonder phonograph

[radiotvnut]

Originally Posted by comradesvox

Oh, and yes I did notice the hot cartridge. This thing can be dangerous. I can't even figure out a way to make it safer with a polarized plug and fuse - as the switch is switching the ac to the chassis! The diagram shows a polarized plug only because I couldn't find an unpolarized plug in visio, but in reality this unit is not polarized.

In hot chassis radios, they used a non-polarized power cord and the switch would be placed in the neutral side of the power cord. Depending on the plug position in the wall socket, there's a 50/50 chance the chassis will be hot. This will also be the case even if the radio is off because of the series wired tube filaments.

The way we get around this problem is to use a modern polarized AC cord and wire the power switch in the HOT side of the AC line. However, this is still not a 100% safe method because if the radio is plugged into a miswired AC outlet, you have a hot chassis on your hands. It would probably be best to get one of those little LED outlet testers to make sure all outlets in your home are wired correctly.

I recently had a '48 Decca 78 rpm child's record player that had a hot chassis. Due to the shielded tonearm cable, even the metal tonearm was hot, along with the metal volume control shaft. If the plug was orientated so that the hot side of the line was going to the chassis and if the user was touching an exposed metal part while another part of their body was in contact with something that had a return path to ground, the results could very well be deadly. It's hard to imagine something like this that was made for kids passing UL inspection, even in 1948.

In later years, they connected a capacitor between the chassis and actual circuit ground. This made things a little safer; but, it's still possible for one to get nailed from one of these.