Homemade solder flux remover – cleaner DIY (Isopropyl alcohol, Ethanol, Ethyl Acetate)

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The use of flux is essential when soldering electronic components. By removing impurities such as dirt, oils and oxidation, it helps to achieve a stronger solder joint. The contaminants could be removed by mechanical or chemical cleaning prior to soldering, however, high temperatures required during the soldering process would cause an element to re-oxidize and thus prevent a successful solder joint. There are essentially three types of flux – water soluble flux, no-clean flux and traditional rosin flux. Rosin flux is highly corrosive so it needs to be removed after soldering, still, why would you want to remove a no-clean flux residue?
There are a few reasons:

  • gummy residue prevents test accuracy when doing in-circuit testing
  • it prevents an adhesion of conformal coating
  • to improve the cosmetic appearance of the board
  • to prevent dirt buildup

The homemade flux remover is able to remove the rosin based, non-rosin based and no-clean flux. It works better than some commercially available products and it doesn’t leave any residue when used properly. It can be used on circuit boards and on most of the plastic parts (discoloration may occur on some plastics).

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HP G62 – CQ62 laptop faulty webcam-101 (not detected) repair or replacement

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Issue

I bought this notebook for a repair and resale. When I asked a seller about the laptop’s history, his reply was “It just stopped working”. As it later turned out, it had numerous problems, one of them being a faulty webcam. After the Northbridge chip replacement the laptop started working. During a testing process, I noticed the webcam isn’t working in Skype; there was no video and the webcam’s control light wasn’t lit. In the Device manager there should be a HP webcam-101 device under the imaging devices or at least an unknown device with an exclamation mark beside it (a possible driver issue).

HP-webcam-101-device-manager

Webcam’s absence in the device manager points to a hardware failure. There are four possible scenarios in cases like this, written from the most likely to less:

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Computer doesn’t boot after vacuum cleaning (black screen, no post)

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Issue

Customer brought in a desktop PC with a no post problem. After turning it on, there was a blank screen and a “no signal” text on the monitor, the fans were spinning and the “power on” light on the front of the case was lit. In a quick conversation the customer mentioned the problem started after cleaning the computer with a vacuum cleaner, while he was trying to get rid of the dust inside. This information shortened the diagnostic process considerably as it eliminated causes such as: bad BIOS flash or Power supply / Northbridge / Southbridge / CPU / RAM / Graphic card fail. In cases like this the problem usually lies in a dislodged connector or RAM sticks / Graphic card which is not properly seated in the slot. Damaged components as a result of the static electricity induced by the vacuum cleaner or an improperly grounded operator are also a possibility but an unlikely one.

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