Monitor woes

So my monitor decided to go crazy on me, intermittently the last week. Sync issues primarily and loss of data to screen.
 I thought it might be cap failure, and was ready to rebuild it.
Not being 100% conclusive I grabbed a spare monitor and hooked it up, but it was too old apparently to work with the computer I have.

 So I reconnected my old monitor up and the problem has not shown up since yesterday.
 I think the DB15 connector has gotten dirty, as pounding on computer & monitor did no good in locating the problem.
 Reconnecting the DB15 connector seems to have solved the problem.

I will go to state surplus this coming week & grab a spare monitor, JIC I do need one.

I HATE these sort of problems. It could have been the monitor or the video card, or something else spooky.