前天接修一台美的变频空调，内机正常有正常的220输出，信号有40V的跳动外机没反应。看着3楼高的墙体从窗户够不着。心里打退堂鼓这时机主说几个师傅看过了说要换主板，价钱要过千你看能修吗？看着机主期待的眼神。说尽量修。于是架好梯子拆盖开机检测板上的指示灯没亮查查5V，有3V多，12V有6V拆板回店里修。副电源是TNY268PM电源切断各负载串灯泡电压还是低心里一阵高兴。断开817电压变高，断电测431，817没问题焊下取样贴片电阻仔细看是273，实际测变为1.8K.273应该是27K才对的啊重新测还是1.8K找了两个电阻串好通电7805前是8V输出5V,标12V输出实际是15V.恢复好电路。再次通电指灯终于亮了，再测电压5V,15V正常。看来是副电源不正常导致外机不工作。装好试机一切正常，这时机主说高啊师傅以后这一排空调就指定你修了，现在那里就有6台要修我不急你看着安排时间来修吧，收了蓝黑宗谁知机主多给一张毛爷爷说拿去买水喝。
The day before the repair of a beautiful inverter air conditioner, the normal machine has a normal 220 output, the signal has 40V jump outside the machine did not respond. Look at the walls of the 3rd floor from the window. Heart back to the drums of the time that the master said a few master said to be for the motherboard, the price to be over you you can repair it? Looking at the owner looking forward to the eyes. Said to try to repair. So the roof of the ladder to open the test board to open the lights do not light to check the 5V, there are more than 3V, 12V 6V demolition board back to the store repair. Sub-power is TNY268PM power cut off the load string light bulb voltage or low heart burst of pleasure. Off 817 voltage becomes high, power off test 431,817 no problem welding under the sampling chip resistors look carefully is 273, the actual measured into 1.8K.273 should be 27K only ah re-test or 1.8K find two Resistance string good power 7805 before the 8V output 5V, the standard 12V output is actually 15V. Restore good circuit. once again power indicator light finally bright, and then measure the voltage 5V, 15V normal. It seems that the secondary power is not normal cause the machine does not work. Installed all the normal test machine, then the owner said the high after the master of this row of air conditioning to specify you to repair, and now there are six to repair I do not hurry you look at the time to repair it, Know the machine owner to give a hair grandfather said to take to drink water to drink.
导读：前天接修一台美的变频空调，内机正常有正常的220输出，信号有40V的跳动外机没反应。看着3楼高的墙体从窗户够不着。心里打退堂鼓这