Replacement of curtains on Xiaomi: deal with IR-filtering in TVs and projectors

Mechanical curtain (aka mechanical curtain) IR-A filter or blade shutter is a critical component in projectors and some Xiaomi TVs that regulates light flux and contrast. You get vertical stripes on the screen, you get a decrease in brightness, or you get a curtain that gets stuck with a characteristic grinding, and you get a replacement from 3,000 to 8,000 rubles, but with the tools and patience, you can do it yourself, saving up to 80 percent of the cost.

In this article, we will analyze the unique nuances of changing the curtain on Xiaomi devices (including the popular models Mi Laser Projector 150, Mi). TV Laser Projector 2 and Mi TV Series TV Q2), You'll learn how to diagnose a malfunction, pick up an original part, disassemble the case without damage, and avoid typical calibration errors after repair.

Signs of malfunctioning curtains: when is it time to change?

The first symptoms of wear curtains are often confused with problems of the matrix or lamp. In order not to waste money on unnecessary diagnostics, pay attention to the following "bells":

• 🔍 Vertical dark stripes in the lighter areas of the image (especially visible on a white background) are a sign that the curtain blades are not fully open.
• 🎚️ Spontaneous change in brightness – the screen periodically “blinks” or becomes dimmer without commands from the remote.
• 🔊 Extraneous sounds from the projector/TV: squeaking, cracking or knocking when switching on or changing a scene in the film.
• 🛑 Mistake. E12 or E24 on the screen (in models with self-diagnosis) - indicates a mechanical locking of the curtain.

If at least one of these signs appears, we recommend to run a test: run on the device white screen (for example, through the Settings menu). → Picture → Test sample, and carefully examine it for stripes or uneven lighting, 90% of the time, this will confirm a curtain problem.

⚠️ Attention: Do not confuse curtain defect with matrix burnout! When burnout, the stripes are static and visible against any background, and the curtain problems manifest themselves dynamically (for example, the stripes "float" when the brightness of the scene changes).

Which Xiaomi models are equipped with a curtain?

Curtain (IR-The filter is not installed on all Xiaomi devices, here is the current list of models where it is present and may require replacement:

Important: LED-Xiaomi TVs (e.g. Mi TVs) TV A2 or Mi TV P1) There's no curtain, it uses a different kind of lighting technology, so if your model isn't on the list, the image problem is more likely to be a matrix or a power supply.

Preparation for replacement: tools and spare parts

Before disassembling the device, prepare everything you need. To replace the curtain on Xiaomi, you will need:

• 🔧 Setting screwdrivers: PH0 (cross, for most of the screws of the body) T5 and T6 (stars, for internal fastenings) 1.5 mm (flat, for slapping latches)
• 🛠️ Plastic blades (for safe opening of the body without scratches).
• 🧲 Magnetic mat or screw box (so as not to lose small details).
• 🔍 loope USB-microscope (to examine the contacts of the curtain for oxidation).
• 📦 Original curtain (article depends on model, see table below).

To select spare parts, use the articles from the official Xiaomi catalog:

⚠️ Warning: Buying a curtain on AliExpress, check the reviews about the seller - often under the guise of original spare parts sell replicas with a resource 2-3 times lower.

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Before ordering the curtain, take a picture of the old part on both sides - this will help the seller to choose the exact replacement if the article is unknown.

Step-by-step instructions for replacing the curtain

The replacement process is different for projectors and TVs, and here is the universal instruction for Xiaomi laser projectors (the most common case). For TVs, the steps are similar, but disassembling the case is more difficult, requiring the removal of the stand and the back cover.

Disconnect the device from the network for 30 minutes (discharge of capacitors)|

Take a picture of all the cables before disconnecting.|

Sign the screws with a marker (they may differ in length)|

Wear an antistatic bracelet or touch a grounded object

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Step 1: Disassembly of the hull

1. Turn the projector down on a soft surface (for example, a towel).

2 Unscrew 8 screws on the back cover (use a screwdriver). PH0). In models Mi Laser Projector 2 additionally need to remove the decorative grille of speakers – it is attached to 4 latches.

3. Carefully apply the plastic blade to the back cover, starting at the corners. Be careful - there may be power wires inside that are easy to tear off!

Step 2: Access to the curtain module

1. Disconnect the plumes leading to the motherboard (pre-photo their location!) In Xiaomi projectors, they are fixed with white latches - they need to be lifted up.

2 Remove the metal screen covering the optical unit. It is attached to 4 screws. T5.

3. the curtain is located to the right of the laser module (in models 150) or on top (in Mi). TV Laser Projector 2. It's mounted on two guides and connected to a 4-wire loop control board.

Step 3: Remove the Old Curtain

1. disconnect the power supply plume of the curtain (carefully pull the plastic connector, do not pull the wires!).

2. Unscrew 2 screws. T6, locker.

3. Remove the curtain by moving it to the left (along the guides). Don't make any effort - if it doesn't come out, check if all screws are unscrewed.

Step 4: Installation of a new curtain

1. Before installing a new part, blow out the guides with compressed air - the dust can cause snag.

2. Put the curtain in the grooves and lock with screws T6. Make sure the blades move freely (you can slightly shake the module with your hand).

3. Connect the power plume. Important: the connector should click with a characteristic click.

Step 5: Assembly and testing

1. Place the metal screen and the back cover. Rotate the screws cross-cross to avoid skewing the body.

2. connect the projector to the network and run the test mode (Settings) → System system → Self-diagnosis).

Check the curtain's operation:

• 🔦 Point the projector to the white wall and turn on the maximum brightness mode.
• 👀 Carefully examine the image for stripes or flickering.
• 🔊 Listen to if there are any extraneous sounds when the brightness changes (for example, in the settings menu).

Calibration of the curtain after replacement

Even the original curtain after installation can work incorrectly without setting. In Xiaomi projectors, the calibration is performed through the service menu:

1. Turn on the projector and press the Menu button on the remote. + OK 5 seconds to open the engineering menu.
2. Go to the Shutter Calibration section (some models call it the Shutter Calibration section). IR Filter Adjustment).
3. Select the Auto Calibration option and wait for the process to complete (it will take 2-3 minutes).
4. If automatic calibration does not help, manually adjust the settings: Shutter Open Time: 12-15 ms (for laser projectors) Shutter Close Time: 8-10 ms Contrast Balance: 50-60%

After calibration, restart the device and recheck the image. If the bands are left, try resetting the image settings (Settings) → Picture → Reset).

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Calibration of the curtain is mandatory! Without it, the new part will serve 2 times less due to the uneven load on the mechanism.

Common Mistakes and How to Avoid Them

Mistakes in changing the curtains can lead to even more serious breakdowns, and this is what most often spoils the device:

• ⚡ Undischarged capacitors – if you don’t wait 30 minutes after the power outage, you risk being electrocuted or burning the motherboard.
• 🔧 Twisted screws, which deforms the body and can block the movement of the curtain.
• 🧹 Dust in the optical unit - if you do not clean the guides before installing a new curtain, it will quickly clog and begin to bite.
• 🔌 A damaged plume is easy to break if you pull wires instead of a plastic connector. Always grab a black or white lock!

Another common problem is part incompatibility, like the curtain from the Mi Laser Projector 150" (MDZ-23-AB) It looks like a piece for the Fengmi Cinema. 4K, But it has a different blade pitch, and if you put a curtain like this, it's going to flicker at 120 Hz.

⚠️ Note: If the projector is making an error after replacement E30, It means that the curtain is upside down. Turn it over. TOP case-piece).

Alternative solutions: repair vs replacement

It is not always necessary to replace the curtain completely, and in some cases it can be repaired:

• 🧴 Cleaning and lubrication – if the curtain is ingested due to dust, wash the guides with isopropyl alcohol and apply a drop of silicone lubricant (for example, WD-40 This will extend the life of the part by 3-6 months.
• 🔧 Replacing the drive motor -- 20 percent of the time, the problem is not with the curtain itself, but with the motor that opens it: ~1 200 ₽.
• 📶 Update firmware – in projectors Xiaomi 2020-2021. there was a curtain control error, fixed in software versions 1.4.52 and higher.

Repairs are justified if:

• The device is less than 3 years old (the curtain life is not yet exhausted).
• The problem occurs episodicly (for example, only at high brightness).
• You are ready to repeat the procedure in six months.

In other cases, the replacement is more reliable. For example, in Mi Laser Projector 150 projectors, after 20,000 hours of operation, the curtains thin and begin to let the light through even when closed, cleaning this will not help.

FAQ: Frequent questions about curtain replacement