How to Clean a Motherboard

Why do we use ultrasonic cleaners?

Motherboards that do not work can sometimes be fixed by putting them through an ultrasonic cleaner. However, motherboards should be diagnosed and possibly fixed before they are cleaned. The ultrasonic cleaner removes dirt and debris from the board that can short circuit components. It also removes sticky liquid residues that can be partially conductive, causing random unexpected shutdowns or malfunctions. Ultrasonic cleaning also reaches underneath chips, an area that you cannot get to with a toothbrush or Q-tip alone. Corrosion and residues can cause strange intermittent issues even if you can’t see them. Boards should also be cleaned after a motherboard repair to avoid customer returns.

• {PAUL PICTURE NEEDED of some sort of wine or sticky spill that doesn’t corrode anything but gives you one of those blotches you can see when you put the board to light at an angle}

Ultrasonic cleaner setup

The ultrasonic cleaner should be filled with distilled water only, never tap water! The reason for this is tap water contains mineral impurities which can leave a conductive residue on the board, potentially creating further issues. If you are out of distilled water, ask a manager about purchasing some from a local pharmacy or grocery. If you would like to test a source of water before using it on a target board, you can first test it on a cheap piece of electronics, such as a portable calculator. The liquid we put in is a mixture of cleaning fluid (Branson EC) and distilled water.

Ultrasonic cleaner

The concentration should be approximately 3–5% by volume, so for each gallon of water poured into the ultrasonic cleaner, 4–6 fl oz of Branson EC should be added. In metric, this is about 30 mL per liter of water. Usually we put in approximately 1.8 gallons (6.8 liters) of water, and add 180 mL of Branson EC. The easiest way to do this is fill up the ultrasonic cleaner “to the lip” with distilled water and slowly add Branson as the water heats up.

Ultrasonic cleaner lip

The solution should be heated to 140 °F (60 °C) prior to use.

Ultrasonic cleaner usage

1. Remove any thermal paste from the logic board to prevent it from going all over the board & under chipsets. See image thermal paste on CPU.
2. Remove any sticky, soft shields from the board to prevent them from dissolving and getting under the chips.{PAUL PICTURE NEEDED of shields of new machines}
3. Remove any metal shields that are covering components so that they are not blocking the cleaning of components under them. The ultrasonic cannot clean through metal shields. {PAUL PICTURE NEEDED of shields}
4. Once the cleaner solution reaches 140 °F (60 °C) place the board inside the ultrasonic cleaner.
5. Clean one side of the board for 2 minutes. DO NOT WALK AWAY FROM THE CLEANER. The MOMENT it is done being cleaned, it must be flipped.
6. Flip the board, clean the other side of the board for 2 minutes. DO NOT WALK AWAY FROM THE CLEANER. WE DO NOT WANT TO KEEP IT IN THERE A SECOND LONGER THAN IS ABSOLUTELY NECESSARY.
7. Remove the board from the ultrasonic cleaner, and soak in a container of 99% isopropyl alcohol for 10 seconds to rinse off cleaner residues.
8. Leave the board in front of a fan to dry for approximately one day, ensuring the fan is on.

Thermal paste on CPU

Rapid drying

Sometimes, it may be necessary to expedite a repair for an impatient customer. In these cases, the board must be dried more quickly. Some boards which are less sensitive can be placed in an oven at 150 °F (65 °C) for approximately half an hour to expedite the drying process. You can do this after step 7 in the ultrasonic cleaning procedure - instead of letting the board sit for 1 day, it can sit for 10 minutes, and then be placed into the oven. Please speak with an experienced board technician or management before placing boards in the oven.

Precautions

Glossy vs. matte finish boards

Boards that appear to have a “glossy” finish are more delicate & fragile than boards that appear to have a “matte” finish. Boards that are glossy must be ultrasonically cleaned more carefully - for these boards, only ultrasonic them for 1 minute per side. Affected Apple models include A1989, A1990, .{PAUL PLEASE PUT OTHER MODELS I LEFT OUT HERE}

Risk of board death from ultrasonic cleaning

A working board can be killed by an ultrasonic cleaner. The motherboard is the most expensive part of the machine, and on modern machines often has the data integrated onto it. We must seek to prevent "death by cleaning" as often as possible. Common causes of death are:

• Cleaning at too high a temperature.
• Cleaning the board for too long.
• Leaving the board to soak in the cleaner and walking away - Then forgetting the board is still in the ultrasonic cleaner.
• Powering the board ON before it is fully dry.
• Using inappropriate cleaning materials that are too rough or too harsh on the board.

Soaking for an excessive period of time is a very common reason for board death - which is why we have the rule "Never return to your desk until the board is done being cleaned!" Put a game on your phone or something to make sitting next to the ultrasonic for a few minutes more tolerable.

References

Taken from here: https://docs.google.com/document/d/19Q7x5SVrsQQDYx8sobMnW8k5x59vJI1V-koFSf9QeeY/edit#