Samsung 400pxn Low fan voltage

[roanantelope]

Hi All. I have a Sansung monitor ls40bhzns/edc. The fans (3) have low voltage 7.5 vdc.
At the input to the main board the voltage is 12 vdc and remains at that voltage. If I unplug the fans the fan voltage is 12vdc. As I reconnect the fans one by one the voltage slowly drops to 7.5 vdc. The board is triple layer and the fan circuit is in the middle layer. This makes it impossible for me to trace the circuit. If anyone could assist me I would be very grateful. Many thanks.

roanantelope.