Hi Don
Welcome
I dont know that particular monitor, naturally assuming its a CRT type.
its probable that the 3 pin (usually 3pin rarely 2 pin) PTC Thermistor has/is failing
I used to see it periodicaly in my TV servicing days
Follow the degaussing coil wires back from the screen to the circuit board
it will most likely head back to the early part of the PSU.
The degaussing voltage is usually the mains voltage 110 or 220-240 whatever where you live
Have a look for something like this....
note particularly the 3 pin black rectangular ones, they also are commonly cylindrical and blue or white
see how ya go finding it
report back with maybe a clear/sharp photo ofthat area of the cct board and we can identify it for you
cheers
Dave