In article writes:

the schematic shows a diode between two pins on the ES-50
interface. Did you do that when you built your cable? It seems odd
to me to have components outside the box. There's probably room
inside the connector but still....

You notice that there are some jumpers in the plug, too. This probably
has to do with making it work with something it wasn't intended to
work with. Diodes are tiny and cheap. Any old diode will do. Just be
sure to observe the polarity.



--
I'm really Mike Rivers - )