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What does Ohm's Law have to do with phone repair? Well, it has a lot to do with it. We will explain why. Ohm's Law states that the Voltage is the result of multiplying the Resistance by the Current (V=RxI). This means that in electronics, including phones, these three elements are always present. For example, when we look for short circuits, we look for the resistance (or to explain a little, the resistance to the passage of electrons) to be low. So, we measure with our multimeter in ohm scale, that there are less ohms than normal or even 0 Ohms, and we measure in diode scale, that there are few volts, or 0 volts. You see? In a short circuit, the resistance goes down and consequently the voltage goes down.This is due to Ohm's Law. The lower the resistance, the lower the voltage. Let's apply it to the equation: V=RxI. Suppose we have a voltage of 5 volts which is the result of the resistance being 2 Ohm and the current being 2.5 amps (5V=2 Ohm x 2.5A). This is an electronic circuit that is normal, without failures. Now, however, due to a malfunction, a short circuit occurs that lowers the resistance from 2 Ohm to 0.5 Ohm. Then, in that case, so that the multiplication between the three elements V, R and I is exact, consequently, the three values will change: since the resistance has dropped, the voltage drops and the current rises (the number of electrons rises). Therefore, to find out the cause of a fault on a motherboard, it is important to make measurements with a multimeter.   Want to see how we do it? Don't miss our next videos about iPhone and Android motherboard repairs. Subscribe to our channel and hit the notification bell so you don't miss them.

Rice? No way. We'll tell you the truth: it requires you to be a technician and have experience and expertise. We'll walk you through it step by step. Step 1: Without connecting it to power and without turning it on, open the device and inspect it carefully. Look for any moisture seals. For example, there will be some on the motherboard, on the screen and on the charging flexor, so if any of them is active, in that area of the active seal it is very likely that there are traces of moisture. Step 2: Look at it millimeter by millimeter. Take your time. Don't clean it and don't put it in an ultrasound machine all at once. You must first of all be aware of the area where the moisture is located and then concentrate on it to clean it. Step 3: If you don't see anything and the device is still not working, remove the shielding where you suspect sulfate may be present. Step 4: As soon as you get moisture, sulfate or rust remember the area and clean it with 99% alcohol or acetone. Then blow some hot air on it to evaporate the liquid you have cleaned it with. Step 5: If cleaning the affected part does not repair it and you can replace the part, do it. You can find all kinds of quality spare parts at your trusted supplier 4Phones.es. Now, if it is the motherboard that is affected, you have to make measurements with the multimeter in order to investigate where the short circuit is. It may be that the short is in a component such as a capacitor, a resistor, a diode or under an integrated circuit. If you want a more detailed explanation, check our video: Don't forget to like and suscribe to our YouTube Channel.

During Easter, from the 11th until the 14th of April 2022, we hid some golden eggs into orders of our customers. Customers who were lucky enough to find one of the few golden eggs, could participate in the giveaway that was mentioned in our newsletter, Instagram and Facebook. By posting a picture of the golden egg, lucky finders were able to win 3 amazing prizes. After receiving some creative, funny and lovely pictures, we created a poll of which the following 3 winners were picked:- VIDAU electronics from The Netherlands, who won an Creality Ender 3 V2 3D Printer
- Oficina do Telemóvel from Portugal, who won a Qianli Repair Kit: Apollo Programmer + Henry Phillips screwdriver Set
- i-Repair.net from Austria, who won a Quick TS1100 Soldering Station + QianLi Universal TipsWe wish our amazing winners a lot of fun with their prize. We’d love to see the amazing 3D things you created and what awesome repairs you have done with the help of these products!Participated in our giveaway but unfortunately didn’t win? Or do you want to be sure not to miss any future giveaways and competitions? Follow us on social media and stay up to date about future giveaways, product launches and many more!

Written by Carlos Saca and Carlos Saca Jr. To download the promised PDF with Repair Protocols and Schematic Nomenclatures click here. We are often asked which schematic diagrams we use. In this blog we will tell you. We use the Xin Zhi Zao, and we take this opportunity to tell you that we used to use the ZXW but we will tell you why we prefer the Xin Zhi Zao. We use this schematic diagram for three main reasons: first of all, because it is very complete; it has as many schematic models as the ZXW. In fact, there are times when certain models were in the Xin Zhi Zao that the ZXW did not have. Of course, we must admit that it also happened the other way around, so while it is one of the reasons we have the Xin Zhi Zao, it is not one of the reasons we prefer it. Here come our reasons for preference: because of the technical support material it has. They have repair cases and, above all, block diagrams and diagnostic protocols, called troubleshoot ways. These are super useful for effective board diagnosis and repair. When you study this section, you grow a lot as a technician. Finally, for the costs: while the ZXW is about 50 euros per year, this software can be purchased from 8 euros per month to 180 euros for 20 years (9 euros per year); so seen this way, it can be almost free. If you want to learn more about this fundamental facet of repairs, on our YouTube channel, we have videos in which we teach how to interpret schematic diagrams in a simple way and with supporting material. For example, you can watch our video while we repair a Huawei P Smart and learn more about it:   To download the promised PDF with Repair Protocols and Schematic Nomenclatures click here.

The 4Phones RMA department regularly faces RMA’s that unfortunately must be denied. From incorrectly packaged items to products that haven’t been tested before installing: it’s important to be aware of these easily avoidable inaccuracies. Therefore, we asked our RMA specialists Adnan from our headquarters in The Netherlands and Kashif from our office in Spain which inaccuracies they often notice, so you can avoid your RMA to be denied. The most common RMA inaccuracies according to our specialists 1: Not testing before installing. It is important to test your products before using and installing them. Testing before installing could help you notice any defects in advance. If displays are already installed whenever they arrive at us, we will unfortunately not be able to accept your RMA. 2: Wrong placement of flex cables. Our RMA department often comes across flex cable issues. Most of the products that get denied for RMA approval, contain a damaged flex cable or connector. The damage is caused by incorrect placement during installation or bending of the flex cables. Remarkable is that most denied RMA’s come from iPhone series 7 and 8 displays that were harmed during installation. Especially these series require to be installed very carefully, because any lack of precision could lead to a harmed touch or display. 3: Removal of protective foils. The protective foils should not be removed before returning the products. Don’t remove any foils until sure it is going to be installed. Make sure the product is as close to its original state (which includes the foils) before claiming the RMA, because otherwise it will be denied. 4: Incorrectly packed returns. Products should be returned in a way that is closest to its original state. This means that RMA’s should contain the original packaging. Another important thing regarding the packaging of the returned product, is the protection. Products should be carefully packed by using bubble foil, enough layers of carton or proper boxes. This way, we’ll more surely receive the package in the state in which you shipped it. 5: Sending products that aren’t ours. Every now and then, we receive so-called returns that actually come from another supplier. Make sure that the returned product is 100% ours before shipping. We can tell by the visible and invisible markings what belongs to us and what doesn’t. 6: Returning without mentioning the problem or defect. Sometimes we receive products of which we don’t know what is exactly wrong with them. Therefore, it is important to clearly mention the problem or defect you’re facing. Give us as much information about the problem as you can, if applicable supported by photos and videos. Ways to avoid denied RMA’s The best way to avoid denied RMA’s, is by keeping the things listed above in mind. In order of approval, products should be returned precisely and carefully. Before submitting and sending your RMA, we ask you to send us additional information about the problem or defect, eventually supplemented with photos or videos. This speeds up the processing of your RMA and can sometimes even help us solve your problems from a distance, without you having to ship and return the product. Do you have any additional questions about your returned products or our RMA process in general? Don’t hesitate to contact us, we’re happy to help!