This is a soft failure, there is a poor thermal stability of components, so after an hour out of order. Image distortion failure, can be made of AGC circuit, AEC circuit. Oscillation circuit fault cause. Maintenance available heating, cooling, the method of quickly find damaged components. GHbservice manual download site
(1) after startup with electric heating element may be down, such as IC201, IC201. C708, C204, Q201, such as main components, when heating C204 fault appear soon. GHbservice manual download site
(2) to use alcohol cotton ball cooling C204, fault and soon disappeared, new 1 u F / 16 v capacitance, fault elimination.GHbservice manual download site