Except otherwise stated here are for line breaks the dummy load. er5service manual download site
 er5service manual download site
For any a TV power supply malfunction, nothing more than three conditions: 1) the main voltage output; 2) the main voltage output is low; 3) the main high voltage output. er5service manual download site
 er5service manual download site
1. The main voltage output and can be divided into the burning and don't blow a fuse fuse two cases. Burning fuse shows that there is a short circuit, and hard and it's not difficult to find problems. For this machine, mainly is the anti-interference circuit breakdown or rectifier filter circuit element, or Q801 c - e interelectrode breakdown, other components damage is caused not to burn the fuse. For the main voltage and the output fault, don't burn insurance issue also involves only by Q801, R804, R805 and C2809, R809 components of self-excited oscillation circuit is open sex is damaged, or by Q802, D804, D803, C810 components standby voltage control circuit is composed of short circuit damage, involving the main pulse width control circuit only Q803 depth (c - e extremely leakage or breakdown), main pulse width control circuit damage will not affect other components meet dummy load when the main voltage output. er5service manual download site
 er5service manual download site
2. Due to the characteristics of mechanical and electrical source circuit, the main low voltage output is divided into "fake load" main voltage is very low, and there are "squeak" sound, "fake load" main power down and "load" (line circuit work) low voltage main three conditions. er5service manual download site
 er5service manual download site
(1) the dummy load when the voltage is very low, and there are "squeak" sound, cause this one by one now as there are two reasons: one is the master have breakdown voltage load short circuit; 2 it is the main voltage output is too high, causing protection SCR I) 815 action.. the first known reason - measure, and in measuring the voltage output has no obvious short circuit, it can only be the second. And cause D815 action, besides the pin welding copper platinum breaking open, it can only be involved in standby voltage control circuit Q802, D804, D803, C810 this four components damage performance variation or open, the actual repair, parallel element method can be used to find the fault.

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