On Sep 28, 7:10 am, Eeyore
wrote:

How do TWO supplies connect to the display ?

Do you actually mean two WIRES (you said pairs of wires originally) ?

GRAHAM:

I must admit that I was assuming that the two 3.5v wires were two
supplies. They could easily be two parts of ONE 3.5v supply.

I was assuming (I know--a dangerous practice) that they were two
supplies because the transformer seems to have a common ground wire
(black wire) soldered to the ground circuit on the power supply
board. Or maybe the black wire isn't a common ground for the entire
transformer....read below:

Besides the outputs I have already mentioned, there is a black wire
soldered to the ground circuit of the power supply board, and this
wire is labeled "CT GND". There is also a grey wire soldered to the
power supply board in another spot, and it is labeled "CT". What does
"CT" stand for?