monitor will come on with a picture for a second or two then turn back
off. power led stays on.

These KDS sets are known for their bad flyback transformers.
Measure the resistance from the anode (big red wire going to top of
picture tube) to ground. Should read open circuit (greater than 200 Meg ohm).
If OK, measure the capactance from the wire to ground. Should read about
2.75 nano-farads. Flyback is bad if less than 1 nano-farads or has any
resistance reading.
I also check the primary winding of the flyback with a transformer ring
tester, but I doubt if you have one.
John