[GreenKeys] 60 ma Loop Power Supply?

[Jeffrey Angus]

Dave Hunter wrote:
> Hi Everyone:
>
> I have my 28ASR running now, but it needs a loop power 
> supply to stop the printer from chattering and to make it 
> respond to the keyboard.
60 mA @ 120 VAC = 600 mA @ 12 vac, so... A pair or 1 Amp 12 VAC
transformers back to back will give you an isolated 120 VAC to make the
loop supply with.

A 1800 Ohm 10 watt resistor will limit the current to about 60 mA.

A word of caution, your 28 may be set up for 30 or 20 mA instead
So I'd suggest using a 4000 Ohm 5 watt resistor to start with just
to see if the loop is happy with that lower level of current.

Jeff-1.0
wa6fwi