“The board is faulty, it needs replacing.” It’s one of the most common things you’ll hear at a repair shop, and it almost always means the same thing: a repair that costs nearly as much as a new device, or simply “it can’t be fixed”.
But a motherboard isn’t a single indivisible part. It’s a circuit with hundreds of components, and when it fails, it’s usually just one of them. Micro-soldering is the technique that lets you find that component and replace it.
What micro-soldering is
Micro-soldering is the repair of surface-mount (SMD) electronic components on a motherboard, working under a microscope with precision tools. We’re talking about parts that sometimes measure 0.4 × 0.2 mm — smaller than a grain of salt — and chips with hundreds of connections underneath.
It’s also known as component-level repair or board-level repair, as opposed to “modular” repair, which only swaps complete parts (screen, battery, whole board).
Which faults micro-soldering fixes
Some common examples:
- Phone won’t turn on due to a shorted capacitor on a power rail.
- Phone won’t charge due to a damaged charging IC, USB controller or protection diode. (If that’s you, check our guide on why a phone won’t charge first.)
- Board-mounted connectors: charging, battery, screen or camera connectors with broken or ripped pins.
- Liquid damage: corroded components and eaten traces after a wet phone.
- No image or no backlight due to a damaged filter, fuse or backlight IC.
- No audio, no microphone or no signal due to a fault in the corresponding chip.
- Laptops that won’t boot due to a burnt MOSFET, a charging controller or cracked chip solder joints.
- Broken traces from a drop or a poor previous repair, restored with jumpers (ultra-fine wire bridges).
What reballing is
Many chips — processors, memory, power ICs — use BGA (Ball Grid Array) packages: instead of legs, they have a grid of solder balls underneath that attach them to the board.
With drops and heat cycles (power on, heat up, cool down), those joints can crack. The chip is fine, but it loses contact. It’s a classic fault in laptops and in phones that have been dropped.
Reballing means:
- Removing the chip from the board with controlled hot air.
- Cleaning the old solder off the chip and the board.
- Placing new balls using a stencil.
- Soldering the chip back in place.
If the chip itself is damaged, it’s replaced with a new or donor part instead.
How a board is diagnosed
Micro-soldering is the visible part, but the real work is the diagnosis: knowing which component to replace out of hundreds. The core tools are:
- Bench power supply: powers the board while controlling voltage and showing the current it draws. The current pattern when you press the power button says a lot about where the boot process stops.
- Multimeter: to measure voltages and look for shorts to ground on each rail.
- Thermal camera or voltage injection: a shorted component heats up, so it’s found by applying voltage to the affected rail.
- Microscope: essential to see and work on components this small.
- Schematics and boardviews: the board’s blueprints, showing which component connects to what.
If you want to understand what those components are, we have guides on basic electronic components and basic electronics concepts.
The soldering tools
- Hot air station to remove and place chips and components.
- Fine-tip soldering iron for small parts, jumpers and connectors.
- Board preheater, which heats the board from below so the chip comes off without thermal shock.
- Flux, low-melt solder, desoldering wick and isopropyl alcohol for cleaning.
Benefits of board-level repair
- Cost: replacing a capacitor or a charging IC usually costs far less than a complete motherboard (which, for many models, isn’t even sold separately).
- You keep your data: replacing the board on a modern phone means losing everything in storage, because the memory is soldered and encrypted to that board. Repairing it keeps your photos and files.
- Sustainability: fewer devices in the bin because of a part worth a few cents.
Honest limitations
Micro-soldering doesn’t work miracles:
- If the processor or memory are irreversibly damaged, it often isn’t worth it (or isn’t possible, because they’re security-paired).
- Boards with widespread corrosion may simply have too much damage.
- Some parts are tied to the device by the manufacturer (certain iPhone parts, for example) and replacing them has limitations.
That’s why the right approach is to diagnose first and give a realistic quote — including saying “it’s not worth it” when it isn’t.
Micro-soldering in Carcaixent and La Ribera
At Systemaxo we do board-level repair of phones and tablets and computers and laptops that won’t turn on, won’t charge or have liquid damage. If you’ve been told your device “can’t be fixed”, tell us what’s wrong: we’ll tell you honestly whether it can be repaired and what it would cost before touching anything.