One good man — the brother of his wife — asked to see the phone for the restoration of its working capacity. Some time ago, the phone began to charge only at a certain position of the charging connector, and now it does not charge at all.
This is a rather common model of the Chinese manufacturer Xiaomi, and first, I wanted to help a good person, and secondly, to open and see if my assumption is confirmed.
The symptoms indicated that the connector had a contact in the MicroUSB connector between the output of + 5V and the circuit board with time. Remove the back cover of the phone.
To get to the connector, unscrew 6 cogs — 2 silver and 4 black. Pay attention to their location — when assembling it will be necessary to spin them into the same places.
It is also worth noting that the screw number 5 in the photo is hidden under the protective sticker with the inscription «MI», I did not immediately notice it.
By revealing the screws, remove the lid. It does not need to disconnect the loops — all contacts between the boards are spring-loaded, which is very convenient.
But before touching the charging connector, you need to de-energize the system — turn off the battery. To do this, we subscribe a battery connector with something non-metallic and disconnect it.
The connector is small, but contains as many as 8 contacts, so be extremely neat with it.
After disconnecting the connector, I connected the charger and measured the voltage in two places: on the connector and on the ceramic capacitor, where the voltage is +5 V from the connector.
As expected, in the first case there is a voltage, in the second — no, that is, the advantage of the advantage really moved from the fee due to the vibrations and the destruction of the solder.
The GND contact (it is a minus contact) is connected to the connecting housing, so that it can be used during measurements.
Turn off the charging connector, we apply a flux, take a soldering iron with a thin stale and carefully disappear. I gave up at the same time the rest of the contacts so that there was no such problem with them in the future.
We wash your fleece board, connect the charger and repeat the measurement. Now the condenser appeared +5 B, which means the contact is restored.
Turn off the charging connector and connect the battery connector, and then we collect everything in the reverse order. Now the phone is adjusted again.
In this case, the problem was on the surface, so it was not difficult to solve it on its own. If the malfunction was in the charge controller, or even more global, would make sense to attribute it to a specialized workshop.
If at least one person this article is useful — it means it was worth writing it.
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