High pitched chirping (tripping) is probably the power supply attempting to run but being dragged down by excessive load.
Usually, do to failure of the line output transistor (short circuit)or less often, the line output transformer. Obviously, there are other possibilities but they are most common causes of those symptoms.
Transistor (is inexpensive) or transformer (is expensive), must be replaced by an engineer with identical parts to the original as they are safety rated. Est. £40-50 Transistor or Est. £90-£100 Transformer inc. fitting and tax.
Cobweb
May 2006