The switch power supply board + B (140 v) terminal voltage is only about 25 v, this machine is in standby mode. Micrometer IC1102 processor (MN152810TTD4) 29} {foot switch control voltage, and at the same time according to the remote control to open, the key, at this time the foot only between 2 ~ 3 v voltage change, when the normal boot to 0 v, standby for 5 v. Indicates, this machine 3 without fault is due to the IC1102 {29} feet caused by abnormal voltage. To further judgment, remove E82 * thing after shutdown, then IC1102 {29} feet and + 5 v side resistance R0 (the resistance on the schematic diagram is not marked, but directly welding on the underside of the circuit board) and then measuring {and} feet and side positive and reverse resistance are about 6 k Ω, and normal should be around 10 k Ω, thus confirm the damage of circuit inside the foot. Considering MN152810TTD4 price Leon and difficult to purchase, so try to external components in repair. Method is: will IC1102 {29} feet and E822 JiaoXiang the jumper wire welding connection, to join in such as the appended drawings of components within the dotted box (c parts can be directly by lap welded on the circuit board). On the remote control to open, the key, as long as the V2c voltage can change between 0 ~ 5 v. QY7service manual download site
 QY7service manual download site
Using MX - 2 movement models in addition to the common panasonic TC - 25 v40rq, and TC - 25 v42g, only the latter more LiYin receiving function. The movement of switch power supply maintenance method "e-paper" has been introduced, in this based on the author's maintenance experience to add the following: QY7service manual download site
1. Many burn IC802 (STR - S6708) power supply is the cause of the thick film blocks D831 diode appear empty welding, the solder joint very discreet, imperceptible. QY7service manual download site
2. Power adjustment Q804 tube, after the damage, should be looking for similar performance darlington tube substitution. Without this thing also can use beta values greater than 250 C2073 substitution, if after substitution phenomenon, it is hard to start at this time can be the substitution of c, b interelectrode Ω a 15 k resistor in parallel, if not yet, again in D824 (6.2 V voltage regulator tube) at one end with a string of 1 n4148, raise the voltage value of D824 to about 6.8 V, the switching power supply can work normally.

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