馃敡馃攱 Recuperando la bater铆a de un Xiaomi Redmi A2. No es cambiar, es analizar y recuperar a un costo menor // Recovering the Battery of a Xiaomi Redmi A2. It鈥檚 Not About Replacing It, but Diagnosing and Restoring It at a Lower Cost 馃挵
Buenas tardes 
Good afternoon,
Hoy en la ma帽ana, hicimos la reparaci贸n de un Xiaomi que no encend铆a. El cliente nos comenta que lo estaba usando, ten铆a un 76% de carga la bater铆a y de repente se le apag贸. Ahora lo trata de encender y no prende. Ya esto lo hemos visto much铆simas veces en Xiaomi, aqu铆 vimos un caso ya de un Redmi 9C, este es un Redmi A2. Vamos a presentarle una vez m谩s nuestro proceder realizando el diagn贸stico y luego la reparaci贸n.
This morning, we repaired a Xiaomi phone that would not turn on. The customer told us that he was using it when the battery was at 76% charge, and suddenly it shut down. Now he tries to turn it on, but it won't start. We have seen this happen many times with Xiaomi phones. We previously covered a case involving a Redmi 9C, and this time it is a Redmi A2. Once again, we are going to show you our procedure, starting with the diagnosis and then moving on to the repair.
DIAGN脫STICO
DIAGNOSIS
1-Presionamos power y vemos que nos sale el indicativo de la bater铆a, pudiera pensarse a priori que la bater铆a est谩 sin carga, o ya en el fin de su vida 煤til, pero tambi茅n que sea un problema en el BMS de la misma que regula su proceso de carga y descarga. As铆 que en primer lugar abriremos nuestro m贸vil, este es f谩cil de abrir. Nunca podemos olvidar extraer primero la tarjeta SIM, pues podemos da帽arla.
1-We press the power button and see the battery indicator appear. At first glance, we might think that the battery has no charge or has reached the end of its useful life. However, there could also be a problem with the battery's BMS, which regulates its charging and discharging process. So, the first thing we will do is open the phone; this model is easy to open. We must never forget to remove the SIM card first, as we could damage it.
2-Una vez abierto completamente el m贸vil, medimos el voltaje que tiene la bater铆a, en este caso tiene 4.029 V, m谩s que suficiente para encender el m贸vil, aqu铆 corroboramos lo que nos dec铆a el cliente, que ten铆a la bater铆a con suficiente carga. Con este voltaje debe estar por encima del 70 por ciento de carga, recordemos que el m谩ximo es 4.2 V correspondiente al 100 %. Por aqu铆 ya descartamos que sea por falta de carga.
2-Once the phone is completely open, we measure the battery voltage. In this case, it reads 4.029 V, which is more than enough to turn on the phone. This confirms what the customer told us: the battery had sufficient charge. At this voltage, the battery should be above 70 percent charge. Remember that the maximum is 4.2 V, corresponding to 100% charge. We can now rule out insufficient charge as the cause.
3-Nos quedan dos hip贸tesis por comprobar, o es el fusible que sabemos se abre y no da paso a la corriente del dep贸sito de la bater铆a a la m谩quina, o es la bater铆a en s铆 da帽ada. Comprobaremos ahora si es el fusible del BMS: pudi茅ramos hacerlo como en otros casos soldando dos cables, uno a la l铆nea VBAT y otro a tierra en placa y con nuestra fuente conectada dar power, en este caso, lo haremos de otra manera. Levantaremos la regleta de la bater铆a y con una pinza colocaremos cada una de sus puntas en cada extremo del fusible, damos power y, en efecto, ahora el m贸vil s铆 enciende. Cuando retiramos la pinza, el m贸vil se apaga de inmediato. Aqu铆 ya tenemos el diagn贸stico. El fusible, que es una de las protecciones de sobretensi贸n, est谩 abierto y no permite pasar la corriente necesaria para arrancar la m谩quina.
3-We still have two possibilities to check: either the fuse has blown and is no longer allowing current to flow from the battery to the phone, or the battery itself is damaged. Now we will check whether the BMS fuse is the problem. As in other cases, we could do this by soldering two wires, one to the VBAT line and the other to ground on the board, and then pressing the power button with our power supply connected. However, this time we will use a different method. We will lift the battery connector strip and place the tips of a pair of tweezers on each end of the fuse. We press the power button, and indeed, the phone turns on. When we remove the tweezers, the phone shuts down immediately. We now have our diagnosis. The fuse, which is one of the overvoltage protection components, is open and does not allow the current needed to start the phone to pass through.
REPARACI脫N
REPAIR
1-Para este caso, si no tenemos el repuesto hacemos un puente de lado a lado del fusible. Estos son muy sensibles, se abren con much铆sima facilidad, el 90 % de los casos de Xiaomi con estos s铆ntomas vienen de este fusible. No importa qu茅 modelo sea, desde los gama baja hasta los gama alta hemos visto esta falla. Para hacer este peque帽o puente, tomamos un peque帽o alambre de fino grosor, por ejemplo, como los cables de auriculares, raspamos sus extremos y, con el caut铆n, lo soldamos de lado a lado del fusible.
1-In this case, if we don't have a replacement, we create a bridge across the fuse. These fuses are very sensitive and blow very easily. In 90% of Xiaomi cases with these symptoms, this fuse is the cause. It doesn't matter which model it is; we have seen this fault in everything from low-end to high-end models. To make this small bridge, we take a very thin wire, such as one from a pair of headphones, strip the ends, and use a soldering iron to solder it across the fuse.
2-Conectamos la bater铆a, probamos a ver si surte efecto, damos power y el m贸vil enciende sin ninguna dificultad. Desconectamos y repetimos el proceso de encender nuevamente para estar seguros y listo, el m贸vil est谩 reparado. Armamos y entregamos al cliente.
2-We connect the battery and test to see if the repair has worked. We press the power button, and the phone turns on without any difficulty. We disconnect it and repeat the power-on test to make sure everything is working properly. That's it! The phone is repaired. We reassemble it and return it to the customer.
Aprovechamos para echar pegamento debajo de la bater铆a, que estaba despegada. Usamos B-7000, que es pegamento transparente. En este caso no podemos echar ning煤n tipo de pegamento que cristalice, pues podr铆amos da帽ar o
la bater铆a o el flex que est谩 pegado al chasis. Esta es una soluci贸n aplicable a muchos otros tel茅fonos, no solamente a los Xiaomi. Hay clientes y t茅cnicos que han cambiado la bater铆a completa por desconocimiento, teniendo que pagar montos de 4 a 5 veces mayores al costo de esta reparaci贸n, que pone en servicio nuevamente la bater铆a.
We also took the opportunity to apply some adhesive underneath the battery, which had come loose. We use B-7000, a transparent adhesive. In this case, we cannot use any type of adhesive that hardens into a rigid material, as it could damage either the battery or the flex cable attached to the chassis. This solution can be applied to many other phones, not just Xiaomi devices. Some customers and technicians have replaced the entire battery simply because they were unaware of this repair method, ending up paying four to five times more than the cost of this repair, which restores the battery to working condition.
Hasta aqu铆 la presentaci贸n de este post. Muchas gracias a los lectores por su atenci贸n. Las im谩genes son de mi total autor铆a.
This brings us to the end of this post. Many thanks to all the readers for their attention. All the images are entirely my own work.
Traducido con ayuda del traductor de Google.
Translated with the help of Google Translate.
Hasta pronto
See you soon!