Yes, it is worth sending the board in for repair, Badbaud said it best, once they are working they work for a long time!
Start by re-seating the connectors on all the wire looms where they connect to the back board. Spray some electrical cleaner or Dexoxit on the pins and unplug and re-plug them several times. Those have a tendency to get oxidization.
As for the monitor, we would need to know which monitor you have specifically to say if one is available just like it. Sometimes they used RGB, sometimes they used Electrohome. It would be best to send your board in for a cap kit. You would only need to send the circuit board, not the entire chassis and tube. K-Lar can take care of both. Their contact information is on the Home page/supporting vendors.
Chris