How to disassemble the power supply from an ASUS laptop: detailed instructions with nuances

Laptop power supply ASUS is not just a “black box” with wires, but a complex electronic device that can fail over time. You can disassemble it yourself for diagnostics, repair or replacement of capacitors, but the process requires caution: there are high voltage components inside, even after disconnecting from the network. If you've never dealt with electronics, it's better to leave it to the professionals - a mistake can cost not only a new power supply, but also your safety.

In this article we will look in detail at how to properly open the power supply. ASUS (using the example of popular models of the series ADP-65JH, ADP-90CD, ADP-120MH), what tools you will need, and what to pay attention to so as not to damage the board. You will also learn how to check the functionality of components after disassembly and avoid typical mistakes that beginners make. If your power supply has stopped holding a charge, is heating up, or is making strange noises, these instructions will help identify the cause.

Preparation: Tools and Safety Precautions

Before you begin disassembling, make sure you have everything you need. Without the right tools, you risk damaging the case or board, and without following safety precautions, you risk getting an electric shock. Even if the power supply is unplugged, capacitors can retain charge up to several days.

Here's what you'll need:

• 🔧 Phillips screwdriver (usually suitable PH0 or PH1) - most power supplies ASUS assembled on such screws.
• 🔨 Plastic pick or credit card - for carefully opening the case latches.
• 📏 Multimeter - to check the voltage on the capacitors before work.
• 🧤 Rubber gloves - for protection against residual voltage.
• 📸 Smartphone for photography — fix the location of parts before disassembling.

⚠️ Attention: Do not disassemble the power supply if it was plugged in less than 24 hours ago. Capacitors can carry dangerous voltages (up to 300V). Before use, check them with a multimeter in DC voltage measurement mode.

Also prepare your workplace: the table should be clean, without metal objects, and the lighting should be bright. If you are disassembling a power supply with external adapter (For example, ASUS ZenBook or ROG Zephyrus), keep in mind that its body is often glued together - patience and accuracy will be required.

Step 1: External inspection and removal of the top cover

Start by visually inspecting the power supply. Please note:

• 🔌 Presence of physical damage (cracks, melting, traces of burning).
• 📏 Model marking (usually on a sticker) - this will help you find the board diagram.
• 🔩 Housing mounting type: screws, latches or a combination of both.

Most power supplies ASUS have a body of two halves, fastened with 3–6 screws. In models ADP-65JH And ADP-90CD The screws are often hidden under stickers or rubber feet - these need to be carefully removed. After unscrewing the screws, try to separate the case with a plastic pick, starting from the seam.

If the case doesn't budge, don't force it - you may have missed a screw or the block is glued together. In this case it will help hair dryer: heat the seam around the perimeter (temperature no higher 60°C) to soften the glue. Do not use a knife or screwdriver as this will damage the plastic.

Remove all stickers and rubber feet|Remove all visible screws|Check the case seam for hidden latches|Use a plastic pick to separate the halves|Take photos of the parts locations before removing the cover-->

Step 2: Removing the Board and Inspecting Components

After removing the top cover, you will see the circuit board attached to the bottom half of the case. In power supplies ASUS the fee is usually fixed:

• 🔩 Screws (2–4 pieces).
• 🧲 Plastic or metal holders.
• 🔌 Soldered contacts (in cheap models).

Carefully remove the board without pulling the wires. Please note:

• 🔋 Swollen or leaking capacitors - a common cause of malfunctions.
• 🔥 Darkened or burnt resistors/transistors.
• 🕸️ Dust and dirt - they need to be removed with a brush or compressed air.

If you see capacitors with bulging tops or traces of electrolyte, they need to be replaced. In power supplies ASUS series capacitors often fail CapXon or Teapo - they can be replaced with analogues from Nichicon or Panasonic with the same voltage and capacitance.

Component	Symptoms of a problem	Possible reason
Capacitors	Bloating, electrolyte leakage	Overheating, exceeding service life
Resistors	Darkening, break	Voltage surge, short circuit
Transistors/diodes	Cracks, burnt legs	Overcurrent
fuse	Broken thread	Short circuit in the circuit

⚠️ Attention: Do not touch the board with bare hands - static electricity can damage sensitive components. Use an antistatic wrist strap or periodically touch a grounded metal object.

Step 3: Diagnose faults with a multimeter

Before soldering or replacing parts, you need to make sure that they are actually faulty. To do this, we use a multimeter in the following modes:

• 🔋 Calling - to check the integrity of tracks and fuses.
• 📊 Resistance measurement - for resistors and transformer windings.
• ⚡ Voltage measurement - to check capacitors (after discharging!).

For example, to check a fuse:

1. Set the multimeter to dial mode.
2. Touch the fuse terminals with the probes.
3. If there is no sound signal, the fuse has blown.

To check capacitors:

1. Discharge the capacitor by shorting its terminals with an insulated screwdriver.
2. Set the multimeter to capacitance (if applicable) or resistance mode.
3. Compare the readings with the rating indicated on the capacitor body.

In power supplies ASUS Often there are malfunctions in the feedback circuit (optocoupler PC817 or microcircuit TL431). If the output voltage “floats” or the unit turns off under load, check these elements.

Step 4: Replace faulty components

If you find burnt parts, they need to be replaced. For this you will need:

• 🔥 Soldering iron (power 30–40 W, the sting is thin).
• 🧲 Solder and flux (better to use Rosin or LTI-120).
• 🔍 Magnifying glass or microscope — for working with small elements (for example, SMD resistors).
• 🧹 Solder Removal Braid or suction.

Replacement algorithm:

1. Heat the terminals of the faulty component with a soldering iron.
2. Remove solder with braiding or suction.
3. Carefully remove the part with tweezers.
4. Install the new component, observing polarity (especially important for capacitors and diodes!).
5. Solder the leads, avoiding overheating the board.

When replacing capacitors, pay attention to their polarity - there is usually a marked “minus” on the board. Also check the ratings: if the original capacitor was on 1000 µF × 16V, put instead 470 µF × 25V This is not possible - this will lead to unstable operation of the unit.

What to do if you can’t find an exact analogue of a capacitor?

If the original capacitor, for example, 470 µF × 25V, is not commercially available, you can install an analogue with the same capacity, but higher voltage (For example, 470 µF × 35V). However, it is not recommended to increase the capacity without calculations - this may disrupt the operation of the stabilization circuits. As a last resort, it is possible to replace it with a capacitor with a capacity 20–30% larger (for example, 680 µF × 25V instead of 470 µF × 25V), but only if this is not critical for the circuit (check the datasheet of the control chip).

Step 5: Assembly and Functional Test

After replacing components, reassemble the power supply in reverse order:

1. Place the board back into the case, making sure that no parts are touching the metal walls.
2. Secure the board with screws or holders.
3. Connect the housing halves, making sure all the latches are in place.
4. Tighten the screws (do not overtighten to avoid stripping the threads!).

Before turning on for the first time:

• 🔌 Connect the power supply to the laptop without battery (if it is removable).
• 📊 Check the output voltage on the connector with a multimeter - it should correspond to that indicated on the sticker (for example, 19V for most models ASUS).
• 🔥 Monitor the heating of the block for 10-15 minutes. If it gets too hot or makes a squeaking sound, turn it off immediately!

⚠️ Attention: If after repair the power supply sparks, smokes or smells of burning, immediately unplug it from the outlet! This is a sign of a short circuit or improper assembly. Re-disassemble the unit and check all solder connections.

Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when disassembling power supplies. Here are the most common:

• 🔧 Using the wrong screwdriver - breaks off the screw splines. Solution: Get a screwdriver with a magnetic tip.
• 🔥 Overheating of the board during soldering - leads to delamination of tracks. Solution: Use a soldering iron with temperature control (300–350°C).
• 🧲 Forgetting to discharge capacitors - risk of electric shock. Solution: Always check the voltage with a multimeter.
• 📏 Incorrect polarity when replacing capacitors - leads to an explosion. Solution: The board usually has “+” and “–” markings.
• 🔌 Using acid instead of flux - corrodes contacts. Solution: Use only neutral fluxes (e.g. LTI-120).

Another common problem is loss of screws or springs when disassembling. To avoid this, place all parts in separate containers or use a magnetic mat. If you lose a screw, do not replace it with the first one you come across - in power supplies ASUS Screws of different lengths are often used (e.g. 3 mm And 5 mm), and the wrong one may damage the board.

If the power supply doesn't work after reassembling, don't panic. Go back to the diagnostic step and check:

• Integrity of the fuse (it could have burned out when turned on for the first time).
• The quality of the solder joints (is there any “cold soldering”)?
• Correct installation of new components (especially transistors and diodes).

FAQ: Frequently asked questions about disassembling ASUS power supplies

Is it possible to disassemble an ASUS power supply without a soldering iron?

Yes, if you only need to inspect the board or clean it from dust. However, to replace components (capacitors, resistors), a soldering iron is required. In some cases, you can do without soldering if there is a fault in the connector or wires (for example, a broken power cable).

How to understand that the power supply is faulty if the laptop does not turn on?

Check:

1. The indicator on the power supply (should be lit when connected to the network).
2. The output voltage with a multimeter (must match that indicated on the sticker).
3. Integrity of the cable (often frays at the base).
4. Operability of the unit with another laptop (if possible).

If the unit produces voltage but the laptop does not charge, the problem may be with the power connector on the motherboard.

Which capacitors most often fail in ASUS power supplies?

In models ASUS Most often they break:

• Capacitors CapXon series KL, KZ (swells after 2–3 years).
• Capacitors Teapo series SC (leaking or losing capacity).
• High voltage capacitors 400V (in the primary power chain).

Recommended replacements: Nichicon (HM, HZ), Panasonic (FC, FM), Rubycon (ZL).

Can I use a power supply from another laptop for ASUS?

It is possible if:

• Voltage (V) and polarity are the same.
• Current (A) power supply no lessthan the original one.
• The connector is the right size (or you can use an adapter).

For example, a power supply from Lenovo with parameters 20V 3.25A not suitable for ASUSwho needs 19V 4.74A, even if the connectors are the same.

What should I do if, after disassembling, the power supply starts beeping?

The squeak is usually caused by:

• Unstable operation of the feedback circuit (check TL431 or optocoupler).
• Short circuit in the output circuit (ring diodes and transistors).
• Overload (turn off the laptop and check the unit without load).

If the squeaking sound is accompanied by heating, turn off the unit immediately - this is a sign of a serious malfunction.