This machine boot after 1 hour, slight line twist, first line completely out of sync, field has been synchronization, serious when no character, sometimes with black screen. To turn it off immediately to boot, fail more frequently.
 
Because of the failure time is relatively fixed, poor contact may be smaller, there should be a parts thermal stability is poor, has gone bad.
 
Maintenance after: synchronous processing circuit in DG plate, with a heat gun to DG panels, and determine the fault in IC8004 periphery. Soldering iron heating respectively, are used to determine a diode D1857, D1858 thermal stability is poor, after in normal.