Hi Darrel,

Many thanks for your reply/explanation. I'll add that in my routines from now on.

Best regards.

-Jimbo-

P.S. Just implemented the -ve supply from the 232 comm's chip to supply contrast potential as recommended by many, as opposed to using a separate psu Works a treat - whole unit is now running off an old mobile phone charger, through a 7805 dc-dc converter