[GreenKeys] Model 15/19 power supply 120VDC

[E.]

1A is needed for the punch… I’ve also measured it and it’s around there.  Too little may stress the power supply.


> On Mar 2, 2026, at 8:07 PM, Brenda Gentry via GreenKeys <greenkeys at mailman.qth.net> wrote:
> 
> Another source of transformers is industrial control transformers. Many have two primaries for 120/240 volts in. If you find one that is 50 VA, the two primaries can be connected one to the line and the other to the load and used as an isolation transformer for a loop circuit.  A model 19 needs a  good bit of  current for the punch, a 250 VA transformer would be plenty for both the punch and the loop. Look around for them on the internet and at hamfests, used ones are often inexpensive.
>      Brenda Gentry, KA2IVY
> On 3/2/26 8:29 PM, Jeffrey Golas wrote: