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Here to Get the Best Guide for Phone Repair Multimeter


Digital multimeter is an important use of cell phone repair, which can be also used to measure all other circuit breakages, usually used in circuit breakage or logical part. In the actual maintenance work, the digital multimeter often uses the grounding resistance method to maintain mobile phones. In this article, Phonefix Shop Team will share more guide for how to use digital multimeter when repairing cell phones.  Hope it will help for your professional cell phone diagnosis and repairs.

As the name implies, the resistance to ground is the resistance of a component to the ground. it is important to use a multimeter diode to stop measuring it (the black pen is connected to the element, the red pen is connected to the ground line), so long as there is a data display, it can prove that the element can form a loop with the ground line, that is, the element can be directly or directly to the ground. The line is connected.

The important application of Digital Multimeter in mobile phone maintenance:

1) lookup the broken line of the main board - accurate and rapid

In the maintenance work, in addition to the replacement of components and software processing for a mobile phone, in addition to the replacement of components and software processing, the broken lines are often unable to be repaired. Therefore, many mobile phones are scrapped because of the broken lines of the cell phone logic board. The "ground resistance method" can be used to accurately determine whether the main board is broken line and accurate. The position of the broken line.

2) judge BGA damage or false welding

In the non opening maintenance, the proportion of logical part damage is very high, and the logic part is welded or damaged, and it is the key point. Now the logical part of the mobile phone (like iPhone CPU, font library, power and so on) is basically BGA package. So, how to accurately judge the logic part of the chip to weld or damage under the minimum risk. It is most convenient to use the method of ground resistance.

3) three basic conditions for the measurement of the ground resistance method

The two measuring points are directly connected without any other resistance (mostly in address lines and data lines). The picture shows a motherboard, A is the font, B is CPU, C is the ground wire on the machine board. In this picture, the El foot of A is connected with the Fl foot of B. Now it is necessary to determine whether there is a broken line between the two points. How should we operate it?

generally, the mobile phone can only be taken off A and B at the same time, and then use the multimeter to measure it, but in practice, after the A and B are taken off, there is no broken line between them, instead of the B, it will cause the unnecessary loss. If the grounding resistance method is used to measure, the result will be different.

More professional cell phone repair tutorials you can get from China Phonefix Shop Team.

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