Archive for the ‘Computer and Internet’ Category

USB Chargers   Leave a comment

A Myriad of USB Chargers

With the popularity of microUSB based charging on latest smart phones, tablets, and even some 2-in-1 laptops/tablets, I have basically quite some chargers around in home, all with a USB to microUSB cable.

The chargers can be characterized with the output voltage and current. Below are some of the microUSB chargers that I have:


Charger Voltage (V)

Charger Current (A)

LG Optimus V 5.1 0.70
Motorola DEFY XT 5.1 0.85
Samsung Galaxy Rush 5.0 1.00
Moto X 2nd Generation 5.0 1.15
Hisense SERO 7 Pro 5.0 2.00
Asus Transformer Book T100 5.0 2.00
HP Touchpad 5.3 2.00

The chargers using USB cable have similar output voltages. Most of them have 5.0V rating. HP Touchpad has the highest output voltage, 5.3V. Their output currents can vary even more.

All the manufacturers warn that only their approved chargers can be used to charge the devices, to avoid damaging the device or charger. Of course this should be followed if possible. But I think we all have the chances that we want to just charge it with any convenient charger that we can grab close by. Can we do that?

In general, higher charger output voltage means more capable in charging devices. For example, if I try to charge HP Touchpad with SERO 7 charger, most likely it would not charge anything, because the output voltage is just too low out of the charger. One the other hand, my HP Touchpad charger is the most powerful one and charges all the devices in my home. I was even successful in reviving almost dead battery of LG Optimus and breaking its boot loop as described in a previous post.

The output current dictates how fast the charger charges the device. For example, with the same output voltage, a 2.0A charger can charge 2 times as fast as a 1.0A charger. Normally more powerful devices have batteries of higher capacities, and use chargers with higher current ratings, so they do not need long time to recharge.

Remember there is always chance of potential damage when using non-approved chargers. Use at your own risk.

Asus Transformer Book T100 and BatteryBar

That’s the end of story for most devices. But a recent exception that I have is Asus Transformer Book T100.

This 2-in-1 laptop/tablet is notorious for picking chargers. Basically, its accompanying charger is slow in recharging the tablet. People try to use some other chargers with higher currents (and similar voltages), but they often find that it is charged even slower. Some people believe that Asus intentionally modified the charging circuit and come up with mods. Some other people report that not only T100 may be picky on chargers, but also picky on USB cables.

I am not sure if it’s really the different charging protocol, or just the voltage loss is too much on long USB cables of inferior quality (thinner metal wires therefore bigger resistance). If you are not in the mood of modifying the charger or USB cable, there is an application called BatteryBar, which can report the charging rate in real-time. BatteryBar Pro is $8, but I find the free BatteryBar Basic version is good enough for my purpose. It is only for Windows though.

Once installed, BatteryBar displays a toolbar on Windows bar. If you click it, it shows more information. While charging, the most important information is the wattage. For Asus T100 and HP Touchpad charger, I do find that a 6-feet-long USB cable would yield only about 2500mW (i.e., 500mA at 5V) charging, but a 3-feet-long USB cable would give about 5000mW (1000mA) charging. That’s a difference between 12+ hours and 6 hours for a full recharge.

For a Windows laptop or tablet, I highly recommend to try BatteryBar for charging problems.

Qualcomm Quick Charge

All the chargers mentioned above are conventional USB chargers. Qualcomm’s Quick Charge technology provides another way to charge the devices faster.

Qualcomm Quick Charge uses the same conventional USB-microUSB cable. However, if both the charger and device are Quick Charge compliant, they can negotiate about faster charging. Quick Charge 1.0 allows up to 10W (5V/2A) charging. Quick Charge 2.0 can use various voltages up to 12V, at 3A current, the charging speed is 36W.

Devices using latest Snapdragon SoCs support Quick Charge 2.0, including phones and tablets. Other devices may support Quick Charge as well. You can check here for certified devices.

You can also find Quick Charge certified chargers here. Quick Charge 2.0 certified chargers can output different voltages. If you check the fine text on the charger, you will not see one voltage like 5V, but instead you will see 5V, 9V and 12V with respective current ratings. The key to charge faster is that the charger outputs high voltage with high current, and the device’s charging circuit would convert it to low voltage with even higher current to charge the battery.

As long as both charger and device conform to Quick Charge, they can come from different vendors. This should make you worry less when exchanging charges for your Quick Charge enabled device.

Qualcomm Quick Charge is backward compatible with conventional USB charging.

  • If the charger is conventional, Quick Charge device behaves like a conventional device, and charging is slow.
  • If the charger is Quick Charge certified but the device is conventional, charging falls back to 5V and is slow. Your device will not be fried.
  • If both charger and device are Quick Charge enabled, they negotiate at a high power charging and charging is fast.
  • Quick Charge 2.0 is also backward compatible with Quick Charge 1.0.

AndroidAuthority has a nice article explaining Quick Charge. The FAQ of Qualcomm Quick Charge can be found here.

The devices keep being more powerful and requiring larger battery capacity, and technologies like Quick Charge will be more popular. In fact, both Moto X 2nd Generation and Asus Transformer Book T100 supports Quick Charge 2.0, per device list. I just bought a Quick Charge certified Aukey charger off Amazon for a little over $10.


This charger is able to output 12V/1.5A, i.e., 18W, which is much more than 2500mW I got before with a regular charger.

Delete Wireless Network Profile in Windows 8   Leave a comment


If you cannot find “Forget this network” when you want to delete a Wi-Fi profile, just use the command line below:

netsh wlan delete profile name=”Your_SSID”

I use “Command Prompt (Admin)” from the Windows button to run the command above.


How to Manage Wireless Network Connections & Profiles in Windows 8

Windows 8 – Manage Wireless Networks?

Dropbox Referral Program For 500MB Extra Free Bonus Space   Leave a comment

Dropbox is a cloud storage service. It is like a remote online drive that you can put your files there. It is slower than your local hard drive, but it is super reliable. A basic personal account is free to open, and it has 2GB free space.

I have been using Dropbox for quite a few years. There are many nice features of it. For me, the most convenient feature of Dropbox is automatic uploading of photos that I take on my mobile phone. I just install the Dropbox app on my Android phone, and set up the automatic uploading. Whenever I take a picture, it would be backed up to my online Dropbox account automatically. It saved a lot of photos when my microSD card in my phone went wrong some time ago.

If you open an account at Dropbox right now, you get 2GB free space. However, if you create a Dropbox account through a referral link from an existing Dropbox user, you will get extra 500MB space, i.e., 2.5GB total free space. The existing user will also get 500MB extra space for free.

If you so happen to need a Dropbox account, you can use my referral link To get the 500MB extra space, you need to:

  • Use the referral link to create a new Dropbox account; and
  • Install the Dropbox desktop application on a Windows, Linux or Mac computer; and
  • Sign in to the installed application with the newly created Dropbox account.

That’s it. You will see 2.5GB (instead of 2.0GB) space available in your Dropbox account. And thanks, this will also add 500MB to my Dropbox account. If you need more space, you can publish your referral link to earn bonus space.

Please note that, for this to work, you have to install the Dropbox desktop application on a desktop computer. Installing the Dropbox app on your Android or iOS phone or tablet does NOT qualify for the referral program.

For details, you can also check with Dropbox Referral Program.

Manage Shared Contacts between Two Gmail Accounts   Leave a comment

Microsoft Wheel Mouse Optical: Fix Button Click Problems   1 comment

I have two of Microsoft Wheel Mouse Optical. I have used them for maybe more than 10 years. They are not fancy, but they have been very reliable for so many years. However, recently both of them have behaved strangely. One did not respond when I clicked the left mouse button. The other one often double clicked while I only clicked the left button once. This is a picture of one of them:


They look a bit old and don’t worth much. In fact, repairing them may not worth the time either. However, they are electronic waste and I don’t bother to go somewhere just to recycle them. So I think I should repair them!

Searching over the internet, I found this nice article: Repair mouse with double click problem. It is about a different Logitech mouse, but it helps a lot for me to open the case. The Microsoft mouse is in fact harder to open because it has two screws and two plastic tabs under the sticky pads. The two plastic tabs needed to be pushed hard while I pried the side of the mouse.

This was how the interior looked like in the Microsoft mouse after I cleaned the dust:


I have highlighted the faulty switch on the circuit board corresponding to the left mouse button. To take out the smaller circuit board and reach the faulty button, I needed to remove the wheel first. Lifting the wheel axle from the plastic holding:



Removing the two screws on the bigger circuit board:


The smaller circuit board is held to the back case of mouse with three half-transparent plastic tabs, use small flat head screw driver to carefully pry them and lift the board:


It is easy to see that, unlike that of the Logitech mouse, the switch component in the Microsoft mouse is monolithic and probably impossible to repair if its internals go wrong or unreliable.

I looked around and noticed the third switch (in blue circle) other than the left (in red circle) and right button switches:


That’s the middle button switch. I use the middle wheel of the mouse often to scroll pages, but I have almost never used the middle button clicks. Obviously, the left button switch has been heavily used for 10+ years and has worn out, but the middle button switch has been virtually unused in so many years. I could swap the left button switch and middle button switch and it does not hurt anything to me!

I took out my soldering iron. Liana and Colin helped to hold the circuit boards (with a great deal of caution as the iron was really hot) and I removed the switches from the boards. They looked exactly the same so I was very careful to put the good middle button switch aside. This was one of the switches:


Then I swap the switches and soldered them back to the circuit board. Connect it to the computer, and verify the left button switch works:


I then closed the cover, tightened screws and re-attach the sticky pads. The switches from middle button should be strong enough to work for quite some years, maybe until Gesture UI replaces the mouse!

Remove Malware “Fast and Safe”   Leave a comment

My wife tried to use her computer with her employer’s VPN. The VPN client did not work until she turned off Windows Firewall. I could have made the VPN client an exception in Windows Firewall earlier, but in 2 days when the firewall was off, her computer showed annoyances.

First of all, her Chrome browser started with an unfamiliar home page, not that she had used. When she visited LinkedIn, there were extra blocks of fishy ads right in the LinkedIn web page. Google search also showed extra funny ad blocks. As contrast, Chrome on my computer does not have this problem.

I checked her Chrome settings, and found two strange extensions. The Chrome on my computer has only one Google Docs extension. I deleted the two extra extensions from her Chrome. After restarting, her Chrome worked fine.

I though it was done. But the next day she said, those annoyances came back to her Chrome again! And she found her Internet Explorer (IE) had the same problem! I went into Manage add-ons in IE, and found fishy add-ons like deal2x, saveas etc. They resided under hidden C:/ProgramData folder. Even running IE as Administrator would not allow me to delete these add-ons. They were rogue add-ons. Very likely, there could be something that would run automatically messing up the system.

A very well known tool to check what run automatically in Windows is Autoruns. This is a green application, just extract the files to a local folder, and run autoruns.exe. It revealed the IE add-ons. I tried to delete them from within Autoruns but it complained it could not find the files, although they were there. More importantly, it showed that AppInit was hooked up by fastandsafe.dll. Hooking up AppInit can hijack Windows API calls, and anything doing that is automatically suspicious. A simple Google search showed that Fast and Safe is malware.

One simple way to remove those stubborn malware is to reboot into Safe Mode of Windows. In this mode Windows loads minimal device drivers and runs least autorun programs, therefore the bad code does not get to run, and we can clean it. It’s a bit involved to boot into Safe Mode for Windows 8 or 8.1. After booting in Safe Mode, I ran Autoruns again, then deleted the AppInit and Internet Explorer entries, then went to C:\ProgramData and deleted those fishy subdirectories. I also deleted the Chrome extensions.

After rebooting, her computer has been normal. Of course, I make sure Windows Defender and Windows Firewall are enabled.

Watch Amazon Instant Video on Android   2 comments

If you want to watch Amazon Instant Video on your Android phone or tablet, you may be surprised to find that there is no such app available on Google Play Store. You can of course try to use the web Browser app in Android, get to Amazon’s website, and log in to Instant Video; but when you click any title, it does not play, and you see this message: “You can watch it on Kindle Fire, mobile devices, game consoles and other compatible devices”. Amazon’s list of Compatible Mobile Devices includes only Amazon Kindle, its new Fire Phone, and Apple iPad/iPhone/iPod Touch series. As you already know, Android phone/tablet is not on the list. It is unacceptable that Amazon Instant Video subscribers cannot use Android phones or tablets to watch the titles.

Android users basically have only one workaround – pretending to be using a Desktop web browser, like watching on your Windows PC.

Install Dolphin Browser

We need a bowser app on Android that can pretend to be a Desktop web browser. Luckily, Dolphin is such a browser on Android that you can set User agent to “Desktop”. That way the web servers would believe you are using a desktop computer than a phone/tablet. You can install Dolphin from Play Store.

When Dolphin is running, touch the little dolphin icon to the right of the web URL box, then choose Settings icon (to the left of Dolphin icon in the pop up), choose Customize, then touch User agent and change to Desktop.

Use Adobe Flash Instead of Microsoft Silverlight

If you think that’s it, you are wrong. Now you run Dolphin, log in to your Amazon account, and get to Instant Video. When you click to watch a video, it does not play and says that it needs Microsoft Silverlight. Silverlight is a web browser plug-in for PC. Amazon does not know your browser is in fact running on Android. It thinks you are running on Windows. The problem is, there is no Silverlight on Android! Microsoft does not provide that support for Android.

Amazon used to use Adobe Flash for playing videos in web browser. Some old posts over the internet worked with that assumption. But Amazon became favoring Microsoft Silverlight from Adobe Flash.

However, Amazon still allows you to use Flash. You need to click Settings in the web page and get to Amazon Instant Video Settings. Scroll down to near the bottom, you find WEB PLAYER PREFERENCES, and you choose Adobe Flash Player instead of Silverlight (Recommended). Now that annoying Download Silverlight message is gone.

Install Adobe Flash Player

But, most likely your Dolphin still does not play the movie. On my HP Touchpad CM10 (Android 4.0.4), Dolphin shows a little cube with a few question marks – basically no Adobe Flash Player is available in my Android tablet. Abode stopped support of Flash Player on mobile platforms a few years back. Most Android systems do not come with Adobe Flash Player installed today.

However, you can still download the stagnant Flash Player 11.1 for Android from Flash Player archives at Adobe. For example, depending on your Android version, you can download:

After the apk is downloaded, just install it and you are done. Now you can come back to Dolphin and reload the page, your Amazon Instant Video now plays!

Update 7/16/2014: Amazon has confirmed that it will launch an Android app for its video streaming service “soon” (PC Advisor).


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