From The Art of Repair
Jump to navigation Jump to search

Learning BLD ( Board Level Diagnosis ) Can be a very challenging hill to climb. Rest assured that other people HAVE climbed the mountain before you and have made it to the top.

The only way you will ever really learn it. Is to immerse yourself in it, and study every day. There is absolutely ZERO substitute for working on devices with issues to help you learn.

Learning fundamental soldering skills prior to attempting BLD can GREATLY increase your success chances of reviving a dead board. This removes all doubt about electrically sounds joints and proper BGA attachment.

Buy working boards. Remove and replace while keeping functionality. TRAIN FAIL TRAIN FAIL. If you're not failing, you're not learning. Experiment! Just not on a customers device ;)

Tools For Diagnosis


  • You're Brain | This is a no brainer.
  • Schematics | The 2D map of a circuit. This along with board views will give you a more complete look at a circuit.

Software for Diagnosis

  • PDF XChange Viewer | Best all around PC based PDF viewer for multi schematic component searching and overall PDF reading.
  • Mentor Graphics PADS PCB Viewer 1.2 | While there is a new version available, the 1.2 version will still activate with their free serials and seems more compatible with available PCB files.
  • ZXW Tool | Boardview USB dongle used for tracing pads around a board, for certain brands of devices. Clean Version 2.3 of ZXW
  • KiCad | General Boardview software for Linux


  • USB PowerAmp Meter | Easy way to check for issues prior to opening the device.
  • External Battery Pack | Combine one of these bad boys with a high quality USB Power/Amp Meter and your going to be rocking.
  • DC Power Supply | A diagnostic necessity. This will allow you to power on dead boards / devices and apply power directly to specific spots on the board if need be.
  • Multimeter | Multimeters are used to check everything from voltage to continuity, another essential in diagnosis.
  • Micro Probes | Cant test what you cant touch right!
  • SmartTweezers | Good quality smart tweezers will allow you to check a component, and see its specs without having to look it up on a schematic.

Safety Gear

  • Solder Fume Extractor - This will filter out the toxic smoke that comes from soldering. If your doing volume, get a nice one. It's possible also if you have an open window to just use a cheap 200cfm 4in inline fan with some ductwork to vent it out the window for like 50$. Attaching a big carbon filter at the end and moving it away from you can work decently as well.
  • Nitrile Gloves - Not really a tool, but a great way to combat all the germs and chemicals used in the soldering process. Make sure they are decently snug. I would buy all the sizes and see which really fit the best, before you commit to a large amount.

Tools for Microsoldering

Necessary Materials

  • Solder - Essential metal alloy used to bond two other points together. 63/37 is good because of it has a eutectic point instead of a plastic range and allows you to work more intelligently.
  • Solder Paste - Tiny balls of solder suspended in flux. Used in conjunction with hot air to easily create perfect joints.
  • Low Melt Solder Alloy - Don't crutch on this, but good to have in a pinch or in application specific repairs. Low melt alloys melt at a much lower temperature than normal solder.
  • Soldering Flux - Another soldering essential. To put it simply, flux keeps your work free of oxidation buildup. It is used just as much as the solder itself.
  • Tip Tinner - This helps keep your iron tinned and free of oxidation. Part of a healthy soldering tip lifestyle.
  • Desoldering Braid - Desoldering braid is finely braided copper wire, it is used in conjunction with a soldering iron or hot air reflow machine to soak up the wetted solder on a PCB. Try to find something name brand. A lot of the generic stuff doesn't hold a candle to what's out there in terms of quality.
  • Jumper Wire - Great to have if you pull up pads or need to jump a connection. While you can generally use any appropriate gauge wire. It is a good idea to get something coated. Also great for injecting voltage into a test line.
  • Microsoldering UV Glue - UV reactive compound that is used for many procedures, such as holding things like jumpers in place, or fixing the coating on a PCB, use your imagination. It comes in a few colors, no difference in any of them usage wise.


  • 99% Ethyl Alcohol - Paired with a cotton swab and some extra low temp hot air (100c) you should be able to clean up most flux messes! WARNING Do NOT use this in an ultrasonic cleaner.
  • 99% Isopropyl Alcohol - Some people also like to use ISO to clean boards, same technique. WARNING Do NOT use this in an ultrasonic cleaner.
  • Ultrasonic PCB Cleaning Fluid - Ultrasonic cleaners are made for a variety of different industries. Make sure you find the the proper detergent. This doesn't include ISO and ACETONE or BABY OIL or anything that your grandpa said he used in the 70s to clean stuff.

Useful Things

  • Cleanroom Cloth - Gear for all types of cleanup and can be used with your favorite cleaner. Usually best to buy in the 400pc packs,
  • Cotton Swab - Used for cleanup, make sure to buy solid core wood or the hard cardboard type, never the plastic ones, they melt and are weak!
  • Toothpicks - Just a great thing to have when applying flux and solder paste. Also soft on on components and great for unfill removal in BGA arrays.

Tools for Soldering

  • Hot Air Reflow Machine - If not one of the most crucial pieces of the rework arsenal. The hot air reflow machine uses precision hot air at specific airflows to remove and attach components to the board.
  • Hot Air Nozzles - *This will have to be found after you decide on your hot air station. That way you can find out which type of nozzles are needed for your specific model reflow station. Not all nozzles are universal. Different brands use different types of nozzles. Pay attention to this, its important.
  • Soldering Iron Station - A soldering iron is a hand tool used in soldering. It supplies heat to melt solder so that it can flow into the joint between two workpieces. A soldering iron is composed of a heated metal tip and an insulated handle.
  • PCB Preheater - A heating device that can be used to heat up a PCB to a desired temperature. Generally, these are used on high thermal mass boards or for specialized repairs.
  • Microsoldering Preheater - A brand, or even possibly model-specific preheating device that usually conforms to the dimensions of the phone to distribute heat evenly. Mainly seen for iPhones. They come in two flavors as of 2020, single units that are self-contained, or detachable units that you can purchase different molds to match your models.
  • Soldering Tips - *This will have to be found after you decide on your soldering station. That way you can find out which type of tips are needed for your specific model soldering station. Not all tips are universal. Different brands use different types of tips. Pay attention to this, its important.
  • PCB Holder - This device will hold you're pcbs in place while you solder them either in or out of a microscope.
  • Silicone Baking Pads - Some people would rather work on a silicone heat resistant pad.
  • Real Kapton Tape -
  • Fiberglass Infused Silicone Thermal Tape -
  • Micro Tweezers - Once you go microscopic you will need more specialized tweezers for more accuracy.
  • Solder Sucker - Used to quickly pull solder out of a wet joint. Still useful in some situations. But not a necessity.
  • Micro Nippers - Trust me, at some point your going to have to cut through an EMI Shield or something.
  • Microsoldering UV Light - This light is used to cure the UV compound and make it hard as a rock.

BGA Tools

  • BGA Stencils - Stencils to help you accurately use solder paste to ball a chip for rework. These need to be looked up by individual chip.