Later model X-700s, such as yours with that serial number of over 3.000.000, will not have a Tantalum capacitator as there were some problems with it getting more expensive in the 90s, so they switched to something cheaper to make the capacitators which made them more prone to failure.
Mine works perfectly despite having been unused for over 2 decades until May of this year, because it's an early 1982-83 model ( Serial No. 1728471 ) and it has a Tantalum capacitator.
If it was advertised as working i would get a refund and return the camera, X-700s are a great camera that can be found for usually under 100$ on Ebay on good working order, and i would recomend that you get an early one with a serial number of under 2.000.000 if possible.