Xiaomi’s modern smartphones are famous for their functionality, but the initial setup often raises questions among new owners. The Redmi 3S model, released in 2016, remains popular due to its robust metal body and autonomy, but its tray design has its own peculiarities. Incorrect installation of the communication module can lead to the fact that the device will not see the network or damage contacts.
In this article, we will discuss the installation process in detail. SIM-You will learn how to avoid common errors and ensure stable reception of the signal the first time. Careful study of the instructions will help to maintain the guarantee and integrity of the internal components.
Before you start physically affecting the body, you need to make sure that you have all the tools you need. Usually, there is a special paper clip in the package, but if it is lost, a thin needle or pin will fit, the main thing is to act carefully, without excessive pressure, so as not to damage the extraction mechanism.
Features of the design of the tray Xiaomi Redmi 3S
Redmi 3S is equipped with a combined tray of hybrid type, which is an important technical nuance.This means that the user can choose from two configurations: either use two SIM-cards of Nano-SIM format, or one SIM and one microSD memory card. Simultaneous installation of two SIM cards and memory card in this model is technically impossible.
The tray is located on the top end of the body and has an elongated shape. It's important to note that it's not symmetrical in the thickness and shape of the cutouts, so you can't put it back in without the use of force, which is absolutely impossible. The fixation mechanism is made of metal and plastic, requiring careful handling.
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Always check the integrity of the tray before installation: if the plastic is cracked or the metal is deformed, it is better to replace the part so as not to damage the motherboard.
The design provides protection from dust and moisture in the contact areas, but is not completely sealed. Therefore, when removing the tray in dusty rooms, you should act quickly.
Tools and training required
To do this successfully, you'll need a minimal set of items that you normally have at hand, a metal clip about 1 mm in diameter that comes with the tool, and if the original one is lost, you can use a paper clip to straighten one of the ends, or a special needle for the SIM.
- 📌 Special key clip or thin needle to remove tray.
- 📱 Same thing. SIM-Nano-SIM card (smallest size).
- 🧹 Dry soft fabric to wipe contacts if necessary.
- 🔦 Light source for better visual control of small details.
Before the manipulation is recommended to turn off the smartphone, although modern standards allow hot replacement. However, for Redmi 3S and its version of Android, it is safer to conduct all operations when the power is turned off, so that the system correctly recognizes the new module at startup, this will eliminate software failures in the radio module.
Make sure your hands are dry and clean. Fat spots or moisture can oxidize the gold chip contacts, which will eventually lead to poor communication quality.If the memory card is new, make sure it is formatted in the FAT32 or exFAT file system for compatibility.
☑️ Preparation for installation
Step-by-step instructions for removing the tray
The extraction process begins by looking for a special hole on the end of the device. In the Xiaomi Redmi 3S model, it is located on the top edge, next to the headphone jack. The hole is round and slightly recessed into the body to protect against accidental dust.
Insert the sharp end of the clip or needle into the hole strictly perpendicular to the body. You do not need to enter the tool at an angle, as this can damage the internal mechanism of the latch. Smoothly but confidently press until the characteristic click and the feeling of spring resistance.
⚠️ Warning: Don't put too much pressure on the tray. If the tray doesn't extend, check if you've hit the hole correctly, or try to slightly change the angle of the needle, but without jerking.
Once you click, the tray will extend a few millimeters, allowing you to grab it with your fingers. Carefully pull the protruding edge, removing the mechanism completely. Place the tray on a flat surface with a clean side up so you don't lose it and scratch the smartphone screen.
Proper installation SIM-microSD cards
The most important step is to place the chips in the sockets of the tray. Pay attention to the shape of the cutouts: they exactly repeat the outlines of the Nano-SIM card. The chip should lie tight, not stagger or protrude beyond the frame. The contact group (the golden part) always points down to the motherboard when installed.
If you're using a memory card, it's placed in a second, wider socket, and it's also important to be guided, where the contacts look down, and the bevelled angle helps you identify the right side, and make sure that the card is level with the edges of the tray, otherwise it might crack when you close it.
What to do if the card is not held?
There's a common mistake when users try to put a card back in, which you can't do. If the card doesn't go in the notch the first time, flip it over, and if you force it, you break the plastic locks in the tray.
Inserting the tray back into the smartphone
Once the cards are successfully placed, you need to put the tray back in place. It's critical to be guided: the bevelled angle of the tray should match the bevelled angle of the hole in the case. In the Redmi 3S, the tray has a specific shape that prevents the wrong insertion if not force is used.
Put the tray in smoothly, without skewing. It should enter easily, meeting minimal resistance. If you feel a push, don't push, take out the tray, turn it over and try again. A properly installed tray enters the end with a slight click and becomes level with the body.
| Parameter | Slot 1 (SIM) | Slot 2 (SIM/SD) | General requirements |
|---|---|---|---|
| Map format | Nano-SIM | Nano-SIM or microSD | Only one format at a time in the 2nd slot |
| Chip orientation | Contact down. | Contact down. | The golden part looks at the fee |
| 4G support | Yes (main) | Yeah (on switching) | Only one card works on 4G at the same time. |
| Max. SD volume | — | Up to 128GB (officially) | File system FAT32/exFAT |
After installation, turn on the device. The system must automatically identify a new one. SIM-map and request PIN-The status bar will have signal level and network type icons (3G, 4G, LTE).
Network setting and troubleshooting
If the smartphone is turned on, it says no. SIM-"Maps" or "Emergency Calls Only," check the density of the fitting. Sometimes you need to reboot the device to initialize the radio module. → SIM-Maps and mobile networks make sure that the slots are activated.
For the Redmi model 3S It's characterized by two-band support, but in some cases, you need to manually switch between slots to access high-speed Internet. SIM-maps and choose which slot will be used for data transfer by default.
⚠️ Note: If your smartphone doesn’t see the memory card, check its format. Android doesn’t work with the file system NTFS No root rights. Format the map on your computer in FAT32.
For persistent errors (when the system is constantly writing about the SIM error), try to wipe the contacts of the card with a soft wipe or an alcohol wipe. Contact oxidation is a common cause of communication problems on devices that were in active use.
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The main secret of success is the correct orientation of the bevelled corner of the tray and the purity of contacts, which ensures the stable operation of the network for years.