Android Windows

How To Check New & Used Devices For Problems Using Simple Tips & Software

Kannon Yamada 30-07-2013

Are you thinking of purchasing a new or used smartphone or computer? This new device might suffer from a fault or defect. Before you take the plunge, there’s a variety of stress-tests and diagnostics you should perform. While you absolutely must test used electronics, even brand new smartphones and computers can suffer from defects that you may not notice until after a 30-day return policy expires. To this end, testing all newly acquired equipment remains extremely important.


The basic idea of “stress-testing” your devices is to force the CPU to work as hard as possible – if any internal component possesses a defect, stress testing will likely break the device. While not for everyone – particularly those uncomfortable with breaking their device—stress testing provides a great way of discovering potential future issues with the hardware.

This article details several methods of vetting a new or used device on Windows and Android. It covers a selection of mobile apps and desktop programs that can effectively identify problems before you encounter them. Additionally, I detail some of my methods for analyzing used and new electronics.

How To Check An Android Smartphone For Problems

Diagnostic methods for Android devices: The diagnostic method used on a Smartphone differs between new and used devices. A new phone likely comes with some kind of warranty period, whereas a used phone purchased from Craigslist comes with only the warning: caveat emptor, i.e. let the buyer beware. Any diagnostic method should conform to whether or not you’re under warranty.

Because of the complexity in manufacturing modern electronics, oftentimes not all components on a smartphone will work – for most phones you can only test the SIM card slot, SD card slot and USB port. The phone’s sensors, such as the gyroscope or accelerometer, can’t be examined or tested through physical inspection. Fortunately, you can install software capable of scanning your device’s sensors. Two of the best apps for checking your phone out are Android Sensor Box and Elixir 2.


  • Android Sensor Box: After you install and run the app, the start screen essentially shows each of the sensors of your phone. Disabled components will show a red circle with a line through it over the icon. Broken components, when tested, will show erroneous sensor readings. For example, if you use the “Orientation Sensor” and the bubbles don’t move at all, it means the sensor is either broken or miscalibrated. On a used phone, if you don’t need the sensor, it gives you a tack to negotiate for a lower price.

android sensor box


If you frequent Craigslist, as I do, you know that buying used provides one of the best means of acquiring a good smartphone for cheap. It’s also a great way to get ripped off, particularly if you don’t check the phone’s functionality. Although you probably won’t be stress-testing a phone in the presence of its owner, you can use such software as Elixir 2 to make sure you’re not buying a knock-off. You can also use Android Sensor Box to examine your device for potentially dead sensors. However, be aware that not all devices include all the available sensors. Before testing, make sure you know which sensors your phone employs (a Google search will reveal this).

How To Check A Windows Computer For Problems

Diagnostic Methods for Windows computers: New or used computers mostly use the same diagnostic methods. While you won’t be stress testing, or performing a serious diagnostic on a laptop off of Craigslist, you can still test all its ports to make sure you’re not buying something with defective ports. A useful software to run on a used computer is CPU-Z, which will tell you whether or not you’re buying what the seller claims – CPU-Z can reveal the internal components of a computer, including CPU, hard drive and RAM.


Of course, you will also check all the ports on the computer. To do so will require that you bring along a USB flash drive, potentially an SD card and whatever other ports the laptop comes equipped with, such as a PC card, PS2 mouse and SD card.

If you purchased a computer brand new, you have a great deal of options for testing it out within your warranty period. Out of the many applications out there, I suggest using a stress test using Prime95.


  • Prime95: As with smartphones, a computer is only as strong as its weakest component. Stress testing runs the system at its absolute peak and if anything is defective, it will likely fail. Using Prime95 is ridiculously easy — just start the software up and let it run for an an hour on a desktop and around a half hour on a laptop. Don’t let it run overnight, as running your computer at its peak for extended periods can cause serious, permanent damage.

Prime95 Stress Test

  • Stopping Prime95: Also be aware that the program will not stop unless you select “Test -> Stop” from the menu bar. If you don’t stop Prime95, your computer will run very slowly. If you leave it on for too long, it may cause actual damage.

Stop Stress Test in Prime95

CPU-Z System Information

Overall, a good analysis method will combine diagnostic software with stress testing. Even though desktops can take quite a bit of stress before breaking, remember to not run the stress test software for more than an hour or two. And for God’s sake, use common sense.


For those of you seeking to purchase new or used electronics, strongly consider a combination of diagnostic and stress testing software to weed out potential lemons. As many consumers know, most faulty electronics fail within the first year of ownership. Stress testing and diagnostic software may save you a great deal of money.


I can personally vouch for this method. Stress testing successfully weeded out a lemon Asus laptop, well within the warranty period. Handling returns within the first 30-days of a purchase, for most major retailers, is much easier than dealing with the factory warranty, which oftentimes requires that you pay for return shipping.

Anyone else use a rigorous examination process of new or newly purchased used devices? Let us know in the comments.

Image Credits: Stethoscope via Shutterstock

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  1. Deb
    April 5, 2018 at 11:59 am

    Thank you for your help from someone who had no clue..
    Keep it going

    • Kannon Y
      April 5, 2018 at 3:35 pm

      Sorry, I responded to your email without knowing it was in regard to this article. :-)

      Thanks, I'm really glad that it helped!! This article is pretty old at this point. The Windows programs are still current and Elixir 2 is still used on Android. I don't know if Android Sensor Box is still supported.

      Did the article help with a purchase made online? Or in some other way?

  2. Cary Bondoc
    February 21, 2015 at 7:19 am

    Thanks for this, it really helps me.

  3. Alex
    July 30, 2013 at 6:16 pm

    Is there an equivalent version of these apps for iPhones and for MacBooks?

    • Kannon Yamada
      August 1, 2013 at 9:42 pm

      Good question Alex!

      I thought about this for a long time. And, man, I can't really think of anything for iOS. OSX, fortunately, works with Prime95:

      There's benchmarking software available for iOS, but I think that's closed loop stuff, where it runs and then shuts itself down. I would imagine that Apple's very tight control over its app store would prevent stress testing software from making its way to consumers. Stress test software is actually quite dangerous if used improperly. :-(

  4. Saikat Basu
    July 30, 2013 at 8:42 am

    Very useful information. New often may not mean defect free and Murphy's Law is eminently applicable to electronics :)

  5. jkcook
    July 30, 2013 at 8:13 am

    Your picture seems to show an iPhone, but your article doesn't address iOS machines. Are they invulnerable to problems?

    • Kannon Yamada
      August 1, 2013 at 10:26 pm

      Unfortunately, I don't know of any tools for iOS (but Prime95 does work for OSX). I'm sure there are some apps for jailbroken iPhones, but to my knowledge no stress testing app exists within the Apple Store. :-(

  6. likefunbutnot
    July 30, 2013 at 1:32 am

    You've neglected hard disk tests, which for a used or suspect computer can be a pretty big deal. Western Digital (which now owns Hitachi's former drive division) and Seagte (which owns Samsung's spinning disk division as well as the Maxtor brand) are the biggest players in hard disk and each has its own disk diagnostic tool on its web site, Data Lifeguard and Seatools, respectively.

    For drives of less certain provenance, there's a free program for Windows called HDDScan which can do many of the same basic diagnostics.

    It's particularly important to check drives on ANY used notebook computer or any machine that's more than three years old. Most people don't have the tools or technical ability to reload Windows, but putting that aside, no one wants to lose a drive full of music and digital photos, either.

    • Kannon Yamada
      August 1, 2013 at 10:19 pm

      It was mentioned that Parted Magic includes support for RAM and hard drive testing. But you're right, we're better off using the official drive health scanning tools, rather than a third party product.

      If I remember correctly, though, Parted Magic might contain a few first-party tools, too. Anyway, good tips, thanks for sharing!

  7. Matthew Hughes
    July 30, 2013 at 1:04 am

    Excellent read Kannon! Thanks for writing it!