This machine is in normal watch measuring various switch power supply output voltage is normal, shutdown fault occurs to measure the power output voltage of 0 v. XKaservice manual download site
 XKaservice manual download site
"Resistance method was used to measure the power output of all stripes and line output, the output field circuit has no obvious short circuit and leakage phenomenon: to remove protection method forcibly boot, answer the dummy load on voltage is 140 v + B is normal; Remove the dummy load and restore line scan circuit, sound, light, all normal. Measuring Q805 base voltage protection circuit, when the grating normal for OV, grating is bright, suddenly become a 0.7 V, brightness is still within the normal range, but this time grating is line over-current protection circuit protection by mistake. Check the + B (140 v) over current protection circuit, found that output current sampling resistor R834 / / R835 surface charred traces, resistance, cause the protection circuit protection by mistake. XKaservice manual download site
 XKaservice manual download site
After replacing R834 / / R835, restore protection circuit, automatic shutdown fault occurring again.XKaservice manual download site