[GreenKeys] Model 15 chassis voltage?

[John Nagle]

> Date: Mon, 16 Sep 2013 21:16:58 -0600
> From: Trammell Hudson <hudson at osresearch.net>
> Subject: [GreenKeys] Model 15 chassis voltage?
> 
> Is there supposed to be a voltage on the Model 15 chassis? 

   No. That indicates leaky bypass caps or a short somewhere.
There should be infinite resistance between frame and both
sides of the power line.

> All three 
> of the ones that I have tested trip GFCI outlets instantly if I ground 
> the chassis to the green wire on the power cord.  Measurement with a 
> multimeter shows 20-40 volts AC between the chassis and the neutral line 
> on the input when the ground is left floating.  This occurs even with 
> the switch in the off position.

    That should not be happening.  Replace the filter caps.

    I have four Teletype machines, all equipped with 3-wire cords
and plugged into GFCIs.  The last time I got a GFCI trip was when
a Holtzer-Cabot motor from the 1920s  in an early-model Model 14
arced over due to dust.  I cleaned it out and it's been running fine,
although more noisily than GE motors.

				John Nagle