TCL color TV HD34276 can not be activated after standby, the indicator light flashes for a while and then lights up, then press the power button to no response, power off and restart this phenomenon. The user said that if the remote power is turned off and the main power is turned on, the normal viewing can be started. Later it developed into not starting up.
When the power is turned on, the main power supply +B rises from the standby 70V to the normal value of 130V, but there is no line start sound, then the voltage drops to the standby state indicator and the whole machine does not respond. Measure the voltage of 12V and 5V normally, but find that the digital +5VD is low at around 4.8V. Check that the voltage regulator circuit composed of Q205[D1273] is normal, the input voltage is low at around 7V, and the filter capacitor C883[16V1000UF] is normal. D881 rectifier tube failure is unchanged, it is suspected that the current limiting insurance becomes larger, and then the short-circuit R880 [5A insurance] power-on voltage rises to 8.8V, and the high-voltage sound line starts, the grating is trouble-shooting.
There is a little ohmic resistance to the removed insurance measurement, indicating that the damage has been deteriorated. This fault is mainly caused by the lack of digital 5V power supply voltage, which makes the power supply difficult or does not start. Although the voltage is only 0.2V deviation, the digital circuit has higher voltage requirements. As a result, many strange problems arise, so be careful when you are overhauling. Do not ignore the subtleties and take detours.
SHENZHEN CHONDEKUAI TECHNOLOGY CO.LTD , https://www.szfourinone.com