SIMENSSoronaE Dental Unit, full-featured, easy to use, in our major hospitals in the possession of certain. The unique design of the circuit by the 8048 MCU control, maintenance of a more general treatment station complex. Recently, I had a number of fault repair are mixed with the treatment unit, the process of twists and turns.
Symptoms: loss of all functions of the treatment station
Repair process: treatment of Taiwan Power, water pressure normal, but the barometer without instructions. Examination revealed a large amount of water compressed air pipe, put the exhaust purification, the barometer is indicated, but treatment units can not move, mobile instant jet of water, the pressure decreased rapidly to zero. Off pneumatic valve to release the remaining air pressure inside the tubes, then open valve, the phenomenon of repetition. Shows no pressure in the pipe case, the compressed air valve can be crossed machine. Anatomy of the unique structure of this valve was found only in the power-cases, valve does not open, only the same applied pressure up to set value, the valve can open, play a pressure loss of voltage detection and protection role. Check Circuit found that the power connected, the valve 24V DC rated voltage no. Check the main circuit (P board), found that there is a pool of socket X9 Department patina-like spot mark, alcohol wash, they found printed circuit burns out, the local board of carbonization. Clear Charcoal recovery connection, fault still. From the circuit perspective, many labeled DC 24V, an analysis of the DC by the rectifier bridge VEO AC voltage was 20V, but is no AC voltage. Smooth map discovery 20V AC F13 fuse burned, replaced the DC voltage to normal air pressure to restore the machine after the curing of various functions such as mobile phones and were normal. Treatment units can also be down, but the back can only move forward not backward, and forward 90 °, the no longer move. Obviously, the previous failure was also mixed with back trouble. Can be seen from the circuit, down, back, by the first by three separate motors. Electrical wiring back there are three: bl line zero line, sw 220V AC line when connected, br line OV, motor forward, back forward; the contrary, br line connected power supply, back back. State of the motor depends on the relays K1, K2, relay, is controlled transistor V16, Vl7, integrated block J8 (4520), J9 (4516), J14 (4025), J16 (40106).
Principle: According to the back button, through a series of conversion, eventually JI4 (4025, 3 3 input NOR gate) of the third group of 9 feet or gate produces an output voltage transition, triggered J8 (4520, double 4-bit binary counter synchronous addition) of 7 feet R-side, so l pin CL terminal voltage from the "0" jump to "l", triggering transistor Vl6 turn, connected to DC 24V relay K2 pull its contacts 1 , 2 closed, the 220V AC motor access back, back action. As the lift, back by the motor power plug X3.3 and X3.2 introduction of P plates, apparently no power failure. Therefore, the first measurement J14 9 feet high to 5V, press the back button, no change, while the integrated block supply voltage normal, indicating the circuit had been failures. Check symmetrical lifting circuit, press the button, J15 10-pin voltage is 5V to 0V transition, confirmed the previous judgments. J14 9 feet and 1,2,8 footing or door, logic function Y =, 1,2,8 feet as long as the one for "l", 9-pin output to "0." Circuit is 1 foot ground, inputs are "0", does not affect the output state; 8 feet and J14 of the first group or non-doors (back to move the icon labeled) connected to the output of 10 feet; 2 feet and the second group J14 or door (marked with back back icon) output 6 feet, J9 (45l6, the binary can be prefabricated reversible counter) of a pin CL side connection; J9 2 feet Q3 ended output, trigger switch V18 control relay Kl of action, will be back by the motor power input line to br sw line, if K2 is also action at this time, back back. By back before and after the button, J14 of 6,10 feet with no change in output is "0", so the 9-pin output to maintain J14 "1" remains unchanged, no signal to trigger follow-up circuit, logic does not match with the requirements. Down control control check found that the second group J14 5 feet high or abnormal gate, closing the door leading to 6-pin output is constant "0" so that no backward movement back. J14 5 feet further examination, the 5V power source connected through resistor R8, and by the inductance L12 (680 H), normally closed switch S5, cable L9 of the ge. Line, the other normally closed to open S5, L2 of the ge cable lines, terminal 7, br: line, switch s5 'normally closed, grounding terminals 9 series. Clearly, the middle if not open, 5V voltage drop in the R8, the J14 is 5 feet should be 0V. Continuously measuring the loop-to-ground voltage, inductor L12 when detected, the both ends of the voltage 0V and 5V, found that open circuit inductance L12. In the absence of small inductors and put a small resistor 20 alternative, J14 5-pin voltage is O, back before and after the operating normally, feeling failure were excluded. I am a professional writer from China Toys Suppliers, which contains a great deal of information about 12 volt water pumps , rotary vane vacuum pump, welcome to visit!
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