How to distinguish fake / cloned HP laptop AC charging power adapter from the original / genuine one

Simon 10 Comments

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Issue

In this tutorial I will write about how to recognize a fake, copied or cloned HP laptop AC charging power adapter. I believe this is an important subject since low quality Chinese knock-off copies of HP power adapters can potentially overheat or malfunction and present a serious fire hazard. They are usually made from low quality materials, internal circuitry is simple and lacks proper safeguards (over-current, over-temperature and short circuit protection), any kind of product quality control seems non-existent. Power ratings on these things are made up out of thin air since these adapters are not capable of providing near the advertised power. Do not let the appearance of the adapter or even the HP logo on the sticker deceive you, these things are easiest to copy by the counterfeiters, but as you will see; the devil is in the details.

Tools required:


fake HP 90W power adapter
Fake HP 90W power adapter close up. Please ignore the custom warning sticker.

Original HP 90W power adapter close up
Original HP 90W power adapter close up.

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GPS Dropping Losing Signal Issues with Sport Tracking Apps like Endomondo on Android Lollipop and Marshmallow

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Issue

Endomondo or similar Sport tracker applications randomly losing – dropping GPS signal during the workout, when used on Android 5.x Lollipop or 6.x Marshmallow with the screen turned off. Sometimes Endomondo app uses all the available RAM and forces the phone to reboot. This happens even if the “app optimization” in battery menu is turned off. Hard reset of the phone or clean install of Endomondo (tried different versions) also didn’t help.

The workaround described below works with Endomondo for Android, but should also work with other fitness tracking apps if adjusted properly. Disclaimer: It has some negative impact on the phones battery life during the workout, since the screen is not turned off.

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On board audio not working – bypass it with USB sound card or DAC

Simon 1 Comment

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Issue

A friend of mine brought me this mini PC, based on a ZOTAC GeForce 9300-ITX WiFi motherboard. After freshly installing Windows 7 and all the required drivers from the motherboard manufacturer’s website, I connected speakers and noticed there is no sound output from any of the analog audio jacks. This PC features three jacks on the back and two on the front panel. After opening the Realtek HD Audio Manager, I noticed that analog jacks are all grayed out, which means the Realtek doesn’t detect when a device (speaker or headphone) is plugged in. I tried disabling front panel jack detection in HD Audio Manager and thus force the sound output from front panel jacks, even when device is not detected, no dice.
After trying a few more drivers; the latest driver directly from Realtek and a native Microsoft High Definition Audio Device driver, I concluded this is a hardware problem. I tried measuring audio jacks with a multimeter; no short circuits and no open connections relative to the motherboard. The fault lies in an on-board Realtek ALC662 IC chip or its circuit. I could try replacing the ALC662 IC, but since I don’t have one in stock, I opted for a second best option – replacing or bypassing the on board audio chip with an external USB sound card or DAC. Since an external USB sound card sticking out of the USB port would impact the portability of this mini PC to some extent, I decided to tear it apart and connect it directly to the unused USB header on the motherboard.

realtek-hd-audio-manager-greyed-out-when-plugged-in

Below is a picture of the finished product – an external USB sound card or DAC, modified to fit inside of the computer case and connect directly to spare USB header on the motherboard.

External USB sound card or DAC, modified to fit inside of the computer case.
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Firefox not scrolling to Anchor Links Tags position (Solution)

Simon 15 Comments

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Issue

When clicking on an internal link, Firefox doesn’t scroll to the position of the anchored / hashtag / # element, during the first page load. Instead, it jumps to the middle or to the bottom of the page. If user clicks inside of the address bar and presses Enter, Firefox then scrolls to the correct position. Problem only occurs when link is not on the same page as the anchored element. If both are on the same page, Firefox scrolls to the correct position. Bug is not present in other browsers.

Example: If you click on link – GetGui DC charging adapter with ammeter New tab opens and Firefox should scroll directly to the element with ID “getgui-current-measuring-adapter”. Instead it scrolls to the middle or to the bottom of the page, as seen in the screenshot below.

firefox-anchor-link-scroll-bug

Problem occurs because Firefox tries to scroll to the anchored element before the page is even loaded and the element is actually created. Since it can’t locate the anchored element, it scrolls to the middle or to the bottom of the page.

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Laptop battery test with current amp measuring ammeter

Simon Leave a comment

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Go straight to battery’s capacity calculation

Go straight to simple battery functionality test

Issue

When the laptop’s battery doesn’t work as expected, there are ways to test it, without buying a new battery and later finding out, the problem lay in the laptop’s battery charging circuit. There are a few possible scenarios – battery’s capacity could simply drop below the designed rate over time, battery protection circuit could be activated, the laptop’s charging circuit could be faulty, communication paths between the laptop and battery could be open, charging power adapter could be faulty or not supplying enough current to charge the battery or a signal pin on power supply adapter could be broken and thus not properly identifying itself to the laptop.

Tools required:
  • GetGui DC charging adapter with ammeter
  • A charger tip, compatible with the brand and model of the particular laptop. It could be acquired via Ebay if it wasn’t supplied together with the GetGui charging adapter.

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

Simon 2 Comments

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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

Simon Leave a comment

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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)

Simon 3 Comments

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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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