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fu2service manual download site
fu2service manual download site
(2) the dummy load when the low voltage main and problems are mainly in standby voltage control circuit. Mainly Q802, Q803 disconnect Q803) c - e interelectrode leakage, D804 voltage value reduced. So the case most of the device performance, appropriate USES substitution method of maintenance. fu2service manual download site
fu2service manual download site
(3) after pass circuit voltage output below normal, 90 v, can be sure the problem was with the pulse width control circuit, but involves the element is not much, can only be (2803 c - e electrode (dummy load which may have excluded), (3), (4) feet D809, IC801 breakdown, (2), (3) feet of leakage or other damage of components will not cause the voltage drops. Also cannot ignore R808 resistance is increased. When R808 resistance increases, the R808, R828, R810, Q803 over-current protection circuit will be composed of action, of Q801 b shunt is too big, causes the output voltage drops. fu2service manual download site
fu2service manual download site
(3) for MX - 3 machine core the main voltage output increases, due to the characteristic of the circuit, also in two situations: one is false load slightly tall, by pass circuit voltage can be back to normal after the 90 v; 2 it is false when the load voltage is normal, after pass circuit, the main 90 v voltage can not back to normal. fu2service manual download site
fu2service manual download site
(1) when the dummy load the main voltage output slightly tall, standby voltage control circuit has to work, just because of device performance, cause the voltage loop control. Components Q802 amplification ability becomes poor, D804 high voltage value, C810 capacity decreases, D803 performance becomes poor. Because of few components, and components for the damage of soft, had better use substitution method, maintenance in order to quickly find the fault components. fu2service manual download site
fu2service manual download site
(2) for the dummy load when the main voltage output is normal, and by pass circuit can not back to normal after voltage 90 v, the reason is that the main pulse width control circuit is not working. Then can be divides into the main pulse width control circuit composed of Q803, D809, IC801 sampling control circuit and by C811, D807 and T801 power supply circuit composed of two parts to check. The distinction between two parts of the fault point is: whether there are about 7 v voltage on C811, if any, problems in the sampling control circuit, at this time can be short circuit IC801 (2), (3) feet, quick judgment is D803 or Q803 question or IC801 itself has a problem. The short-circuit IC801 (2), (3) feet, if the primary voltage drop to about 55 v, explain IC801 has a problem, it is D803 or Q803 has problem. Then short circuit D809 (3), (4) feet is Q803 D809 still has a problem. If no around 7 v voltage on both ends of the C811, explain the problem in D809 power supply circuit. Through the oscilloscope, intuitive and fast to the cause of the problem. Damaged components mostly open sex, measured with a multimeter, relevant parts of the electrical malfunction can quickly.
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