1. The DH321 integrated block can be replaced by the FSDL321 model. DH321 is the latest single chip low-power off-line switching power supply integrated circuit developed by Fairchild. The power supply voltage output control mode is current type pulse width adjustment (pwm), which is called "green chip".
2, the switching power supply composed of it has a wide range of utility, high efficiency and low power consumptionSmall electromagnetic radiation, simple circuit and other advantages.
3, DM311 and DH321 can not be completely replaced, DM311 starting voltage is 8-10V, DH321 starting voltage is 11-13V; The DM311 operating frequency is 61-73kHz, and the DH321 operating frequency is about 130kHz. The noise may be caused by the DH321 not starting, and its high frequency may also be inconsistent with the auxiliary transformer.
4, DM311 can be replaced by D321 after the circuit comparison is the same, I use D321 replacement after the boot output voltage is positiveMay be the battery quality problems, high internal resistance, large self-discharge. Something else.
3. The line is relatively thin (the wire is relatively thin, the short rent is too large. There will be a voltage drop,) 2. Switch contact is not good. There is also a large resistance, the voltage will be reduced. 3. There's a problem with the wiring section. The unreliable connection of the wiring part (there is a large resistance) produces a voltage drop. 4.
4. The reason for the failure of the output voltage at the output end of the switching power supply is too low, in addition to the abnormal voltage regulator control circuit, there are usually the following three reasons: (1) the performance of the switching tubeDown. This situation will cause the switch tube can not be normally on, so that the internal resistance value of the power supply increases, and the capacity of the load becomes worse.
5, 7 After power-on, the buzzer is small; After checking the low voltage of the 18V power supply, the triode Q5 emitter E, voltage regulator diode DZ, 18V breakdown at the same time, the whole machine returned to normal after replacing the above components. 8 Buzzer sound after power-on; A short circuit is checked for the resonance capacitance C2-0.3μf capacity becomes smaller, IGBT breakdown, the whole machine is normal after replacing C2 and IGBT.
1, can be replaced. The same type of 0265R above can be replaced. DM31Q100 can be directly replaced.
2, directly replace with DH321, and connect the ground VccVFB to the optical coupler pin 4 empty VSTR through the resistor. Connect 300V (678) Pin connect 300V primary. (1) Buck circuit - buck chopper, the output average voltage U0 is less than the input voltage Ui, the polarity is the same.
3. No. DL1065R chip is responsible for the transformation, distribution, detection and other power management responsibilities in the electronic equipment system, SD6834 is used to store files, can not replace each other.
1. SP5624P can be replaced with the common DH321 change. Specific method: DH321 -- SP5624P678 feet -- 56 feet 5 feet -- 300V4 feet -- empty 3 feet --- 3 feet, 2 feet, 2 feet, 1 foot - the optical root 4 feet can be connected to 104 capacitors.
2, can not SP7623HP is an 8-pin DIP package of power management IC chip, generally used in the third generation of household set-top box inside the power board circuit, SP7623HP and SP7625HP, SP5623HP, SP5624HP these four chips can be directly replaced.
3, the power chip SP7625HP is currently most used in the top of the machine. In fact, a treasure is easy to buy, if it is really urgent, you can use versatile Viper22A replacement, you can refer to the application circuit diagram changes, but you need to have a wealth of maintenance experience.
4, power chip sp5623p can be replaced by what model This is not replaceable, buy the original model sp5623 instead of sp5624 can be done? Are there any other models that can be substituted? First of all, rar is a compressed format file, not software.