Author ：Iflowpower – Portable Power Station Supplier
First, there is no flash, the output voltage is low, can not afford to load such a bad first exclude battery poor (battery core has no voltage or voltage), suppose the battery's self-consuming power should be inspected, see if it is protection Board self-consuming capacity caused low battery voltage. Assume that the battery voltage is normal, it is because the entire loop of the protective board is unlocked (the components are solder, fake welding, FUSE is poor, the internal circuits of the PCB board are not passing, the forales are not passing, MOS, IC damage, etc.).
The specific analysis process is as follows: (1), use a meter black list pen to connect the core negative, red table pen, two ends of the FUSE, R1 resistor, the VDD, DOUT, COUT, P + terminal (assuming the battery voltage is 3.8V), Date segmentation, these several inspection points should be 3.8V.
If not, this circuit has a problem. 1, the voltage of the fuse has changed: check if the FUS is turned on, and if the implementation of the Execion is the internal circuit of the PCB board; if there is no problem in the Executive FUSE (failure, overcurrent damage (MOS or IC control failure), Questions have problems (FUSE is burned before the MOS or IC action), then short-line FUSE, continuous analysis. 2, the voltage between the R1 resistors has a change: check the R1 resistance value, if the resistance value is abnormal, maybe it is a duvement, the resistance itself.
If the resistance value has no loss, it may be a problem with the internal resistance of IC. 3, IC test terminal voltage is changed: VDD end is connected to R1 resistance. DOUT, COUT ends are often due to IC duel or damage.
4. If the front voltage has no change, check the voltage of the B- to P +, because the protective plate is not passing. (2), the multimeter red table brush picks the electric core, activates the MOS tube, the black table pen is in turn 2, 3 feet, 6, 7 feet, P-terminal.
1. MOS tube 2, 3 feet, 6,7 foot voltages have changed, then indicate MOS tube implementment. 2.
If the MOS tube voltage is not changed, the P-terminal voltage is abnormal, and it is because the protective plate negative is not passing. Second, short circuit no protection 1, VM-side resistance problems: available multimeter table written IC2 foot, a table pen is connected to the MOS pipe pin connected to the VM-terminal resistor, contributes its resistance value. Watching resistance and IC, MOS pin is no soldering.
2, IC, MOS abnormality: Because of overlapping protection and overcurrent, short-circuit protection shares a MOS tube, if short-circuit malfunction is because MOS has problems, this board should be freely protected. 3, the above is the normal situation, and may have a short circuit abnormality caused by IC and MOS equipment. As the BK-901 that appears in the previous stage is too long in the IC of '312d', the MOS or other components have been damaged before IC's corresponding action manipulation.
Note: It is the easiest to confirm whether IC or MOS is on the easiest, and the direct method is to replace the doubtful components. Third, short circuit protection is not self-recovery 1. The IC used in the plan is originally not self-recovery, such as G2J, G2Z, etc.
2, the instrument setting short circuit recovery time is too short, or the load is not removed when the short-circuit test is shorted, if the short circuit is short-circuited with a multimeter voltage file, the sheet is not removed from the inspection end (the multimeter is equivalent to a few megaby load). 3, P +, P- Of the leakage, such as the presence of impurities, with impurities, yellow gum or P +, P-room capacitor being broken, ICVDD to VSS is broken. (Only a few k to a few hundred k).
4, suppose, there is no problem, maybe IC is broken, can verify the resistance between ICs. Fourth, the internal resistance is 1, because the MOS internal resistance is relatively stable, there is an internal resistance, and the first suspicion should be a component of the FUSE or PTC to relatively simple episodes. 2, assuming that the FUSE or PTC resistance is normal, then the protective plate structure detects the via resistance between the P +, the P-pad and the components surface, and may have a microcontrolled phenomenon, and the resistance is large.
3, assuming that there is more than the problem, you must doubt whether MOS has an abnormality: the first conviction welding is no problem; the thickness of the board (simple bending is simple), because the bending may cause the tube welding to be abnormal; Put it under the microscope to observe whether it is broken; finally use the multimeter to test the MOS pin resistance value, see if. V. Id abtennation, ID resistance itself because of duel, cracking or due to the resistance, it can be unexpected: can be both end welding resistors, if the free welding ID is normal, the electrical resistance is resistant, if cracking, the resistance will be in heavy Welding from the middle.
2, ID via does not turn on: can be used to test both ends of the hole. 3. There is a problem in the internal line: can be scratched to protect welding paint to see the internal circuit has no disconnection, short circuit phenomenon.
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