The machine boot does not work, no display. Lighting the lamp plug door, hold that fuse in good condition, there is no serious short circuit problem. LCD screen without any display, background light is not bright, press all the buttons don't respond, open the preliminary judgment was no power supply or damage to the computer control part. Open shell, observing the internal parts, found no appearance damaged signs. Control circuit power rectifier circuit boards, capacitance, diode, triode, and solder joint earnest observation, found no signs of damage or virtual welding. HHmservice manual download site
 HHmservice manual download site
The circuit board with step-down transformer. Careful observation circuit line, see the control part of the direct current is regulated by discrete component, voltage regulator triode is Ql0, connection Ql0 zener diode as ZD10 base. Using pointer multimeter on road test Ql0, ZD10, no breakdown short circuit. In order to further check the Q10, ZD10, pull the magnetron terminal (magnetron circuit does not work), electricity, measuring Q10c voltage for about 10 v, e, the base voltage of 0 v, and ZD10 on both ends of the voltage of 0 v, when the electricity estimated ZD10 breakdown. Remove the ZD10, see is the nominal 5.6 V voltage regulator tube, actual and no breakdown. To be on the safe side, look for to a 5.1 V voltage regulator tube substitution. Electricity of commissioning, screen display, buttons also have a reaction, but only the top two rows of buttons is responsive, "start" button is no response, exert oneself to do more than press the "stop/calibration" button several times also have a reaction, but not every time according to the reaction. Owner said machine damage all keys are valid before, there is no pushing or ineffective. Button control integrated piece of damage? HHmservice manual download site
 HHmservice manual download site
ZD10 and control integration block and damage is unlikely. Is 5.1 V voltage regulator tube voltage value is low, still new in stabilivolt no voltage stabilizing function, the output voltage is too high, the integrate control block was damaged? Detect ZD10 around on both ends of the voltage of 5 v. On the 5.1 V voltage regulator tube string of a diode, the voltage value reached around 5.8 V, commissioning, no progress.

 2    1 2 Next Last