|Quick Guide to Fixing Hardware|
|By Howard Fosdick on 2012-12-31 20:26:59|
|Last month, I explained
why I use generic desktops and laptops running open source software.
and inexpensive. But this presumes you can fix them. I believe that
even those with no
hardware training (like me), can identify and fix most hardware
problems. To prove it, here's a quick guide. Feel free to
add whatever I've missed.
Here's the outline --
Don't jump to conclusions. Run free diagnostic software for problem identification:
Now that I've told you not to jump to conclusions, I'm forced to do exactly that in this article, due to space limitations. My bad!
overheating. Laptops are prone to this because they cram so much circuitry into too small a package for easy cooling.
Every computer has internal sensors that immediately shut down the system to prevent electronics damage if the temperature gets too high. Since you can not relate the timing of the shutdowns to your actions, they appear random.
View your laptop's internal temperatures by running a free monitoring app. Download SpeedFan or other free monitors for Windows or use lm-sensors for Linux.
To fix overheating, ensure all fan(s) are spinning when they should. Unclog the air vents. Make sure you aren't blocking the vents by placing the laptop on your lap or pushing your desktop up against a flush surface. Don't pre-heat a laptop by leaving it in the direct sunlight or in a car window. Use the computer in an air-conditioned room.
Open the computer and remove dust, especially that coating circuitry. Since static electricity kills electronics, don't rub down circuitry with a dust rag. Blow it out with an inexpensive canister of compressed air.
If this doesn't fix your problem, you may need to replace the fan(s). Fans burn out as their ball bearings fail. If the computer has a CPU heat sink (a metal flange that draws heat away from the CPU), you may need to re-seat it. Anyone who's downloaded their computer's service manual can perform these procedures so long as they exercise care. Here are good generic instructions with pictures.
Some brands will give you "beep codes" or "blink codes" to tell you what's wrong. Look in the doc to decode them.
If not, this one's tough to diagnose. You need a methodology that helps you find the problem.
If you can't get to the BIOS panels, you have a hardware problem. Turn off the computer, open it up, and write down where every wire, insertable adapter card, and connector attaches to the motherboard and the devices. Record this so you can reattach everything later. Then disconnect every wire or plug from the motherboard, except for the power connectors from the power supply. Detach all devices. Remove all adapter cards and all memory.
Now you're down to a naked motherboard with its CPU, attached to the power supply. Insert one good memory stick into the first slot nearest the CPU, attach a working display (with a video card you know works, if necessary), and turn on the computer. If you can't access the configuration or BIOS panels now, the motherboard or CPU circuitry may be bad. Visually inspect the motherboard for leakage, especially near the capacitors and battery. You might succeed in cleaning up leakage, but most of those boards are goners.
If the system does display the BIOS panels, the motherboard and its embedded circuitry is good. One at a time, reattach each connector or cable or insertable adapter card. After reconnecting an item, turn on the computer. If you can still get into the BIOS configuration panels, you know that whatever you just attached is not causing the freeze-up or failure. As soon as you attach an item and the computer dies, you know that that component was the problem.
Here's an example. My friend's year-old computer completely baffled him. It would start up, display the "HP Welcome" panel, and freeze. He couldn't get into the configuration panels. I stripped the system down to the Motherboard+CPU+OneMemoryStick+Display+PowerSupply. Then I powered on and got into the BIOS panels, so I knew the motherboard and CPU were good. Then I attached each item, one at a time, and booted after each, and got into the BIOS panels. Until I attached the SATA disk drive! Then the symptom re-appeared. We replaced the defective disk and the system has worked fine since.
This methodology is time-consuming but it's a surefire way to identify a defective component. It identifies these problems:
Don't assume that one socket in a power strip is working just because the other sockets in the strip work. If you just upgraded memory verify the seating of the ram sticks.
Check the wire that goes from the Power On button to the motherboard. If this doesn't connect you're not turning on the computer at all. Is the power supply (PS) working? Did its fan spin when powered on? Is the PS properly connected to the motherboard? If you have a spare try the motherboard with another power supply to see if a burnt out PS is the problem. Find how to diagnose PS problems here. If you have a volt-ohm meter (VOM) verify the current.
If these procedures don't work, try the disassembly/reassembly procedure above. Sometimes you'll find a short caused by improper connection this way.
Before you replace the battery, write it down any unique configuration information still in your BIOS panels. Then, pry it out and replace it. They cost only a few bucks. After you install the new battery, update the date and time and re-enter any unique configuration info into the BIOS. Here's how the battery might look on a desktop's motherboard:
Courtesy: www.PCTechNotes.com and www.TechNibble.com
If your mouse is optical, the only cleaning you need to do is to ensure that no lint is clogging the optical opening beneath the mouse. Sometimes optical mice don't track well on glossy or transparent surfaces, including some mouse pads.
If your plug-in mouse doesn't work at all, ensure the connection is secure. Verify the operating system is using a valid mouse driver. Test your questionable mouse on another computer or plug in a different mouse to your computer. Reboot and test. This shows whether you have a dead mouse rather than a software issue.
If your mouse is wireless, the most common problems are: (1) a dead battery (2) a wireless connection problem (3) device drivers that are not correctly installed, or (4) a dead mouse. Check the batteries first. Ensure the wireless adapter or USB linking device is securely plugged in. Verify the drivers. Use the wireless control program to diagnose and resync the mouse. Try resyncing the mouse by powering everything down, then rebooting.
Desktop keyboards are so cheap you might as well buy a new one for all but the simplest repairs. Laptops are another matter, with their embedded keyboards. See how to repair individual keys here. You can also buy a replacement keyboard for your specific model of laptop and install it. This is generically described here and model-specific information is available here. Hiren's Boot CD includes keyboard testing programs.
What if you spill water or a drink onto your keyboard? Turn everything off immediately. Pull the power cord or push the Off button. Do not take the time to perform a graceful shutdown! The longer electricity goes through the electronics the greater the chance for permanent damage.
Do not touch or move the keyboard. Wait a full day to ensure everything has dried out. Then, turn on the system. If you're lucky it will work.
Cleaning the keyboard with rubbing alcohol or electronics cleaner may be in order if you spilled a drink that will become sticky after it dries. If you spilled water, don't bother.
The principle about wet keyboards applies generally to computer electronics. I've picked up computers left out in the rain or snow, let them dry out, and used them without any ill effects. Just dry them out completely before powering on!
Desktop displays are black boxes. The usual remedy is replacement. But verify you don't have a device driver or software issue before junking your display. With laptops you have to buy a replacement screen for your specific laptop model and install it. Here are generic video instructions for replacing a laptop display and here are model-specific instructions. Anyone can successfully replace laptop screens and keyboards -- if they download model-specific documentation and follow it.
Sometimes you'll get a stuck pixel on a LCD screen, a pixel that inaccurately remains an out-of-place color like green or red. Use a felt cloth to gently rub around the bad pixel in a circular motion. If you can get the pixel to light properly, hold the pressure there for a minute or two, and this often fixes it.
new ones are cheap. But first check all connectors, ensure the OS recognizes the device, and that you have a working driver installed.
What if the problem is sporadic? Try cleaning the drive with these three cleaning techniques. Another possible cause is differing calibration between drives. It's possible to write a disc on one system and find another unable to read it. Determine if you have a calibration difference by testing multiple discs on several different drives.
You might find that your drive works well with certain brands of disc media but not with others. Media differences can cause sporadic problems even with healthy optical drives. Remember that there are many optical media standards and that you have to match them properly to the drives that use them. While current drives support muliple media standards, you can't always mix all media in all drives (DVD+R, DVD-R, DVD+-R, DVD-RAM, Blu-ray, CD-RW, CD-ROM, etc).
What if your problem is a particular disc? Clean the disc by gently rubbing it from the inside towards the outer edge. Remove any fingerprints. Sometimes wiping with a dab of distilled water will work. Other times, more aggressive techniques are necessary. This article has a progressive list of steps you can work through to restore a disc to a readable state. It includes my favorite -- cleaning the disc with toothpaste. Read the article before you try it.
What if a CD or DVD gets stuck in the drive? Look closely at the drive face and you'll see tiny hole. Stick a straight pin in there and push a lever that will mechanically push out the tray. Do this with the computer powered off since it is solely a mechanical procedure.
transient (sporadic). If you suspect a memory problem, run an intensive memory checker utility like Linux's Memtest86 or Hiren's Boot CD. You can also set the BIOS to quick-test memory upon startup at the expense of a longer boot.
When you add memory into your computer, ensure it's seated correctly before booting. If the memory is not inserted properly most computers will beep and refuse to boot, telling you to re-seat. Hopefully no damage resulted. After adding memory, enter your BIOS configuration panels to ensure it's properly recognized before booting all the way into your operating system.
"Operating System Not Found"
When booting your computer, you might get an error message like one of these:
To fix a bad MBR or PT, run a program to rebuild this data. Boot a Live CD like Puppy Linux and select its option to rebuild the MBR and PT. Or use the very thorough free TestDisk utility. Here is a complete tutorial on it.
OS Detects the Drive But You Can't Access Your Data
Sometimes Windows knows a drive is present but won't let you use it, or it tells you the drive needs to be formatted. Or maybe it just shows a blank drive that doesn't contain any data. Or it won't show its properties or let you format it. Usually this means a software problem: filesystem corruption.
You can fix a filesystem to recover all or nearly all of your data. Here is a quick list of fix/recovery tools (with more here):
It's possible to have a hardware problem that shows the same symptoms. Dirty contacts on the underside of the drive are one cause. This article has photos that lead you through how to clean the drive contacts simply by rubbing them with a pencil eraser.
Drive is Not Detected At All
First make sure that drives have fully connected power and data cables. You could get a variety of errors from this but "drive not detected" is common. Check the data cable connection to the motherboard as well as the side that connects to the back of the drive.
Another cause of "drive not detected" problems is a failed logic card on the drive. This is the circuit board attached to the underside of the drive. The board circuitry may fail over time due to the heat coming off the drive and the temperature differential from the powered-off state.
Take off the drive board and replace it with another. You can buy one on the web or take one from another drive. The key to success is that the logic board must be for the exact same drive. If not, it will not work. Obviously, you'll only go to this trouble if you really need the data on the drive and you have no backup!
Drive Makes Clicking Noises
This is the infamous Click Of Death. Drives make clicking noises when they have to move the disk arm multiple times to retrieve data. The drive is not functioning properly and this is its error correction procedure. Your drive may fail very soon! Copy any data you need off there immediately. You may have limited time so copy files in priority order.
If you can not get in to copy data off by normal means, here is a procedure that extracts data from even the most recalcitrant drives. It's more detailed than I can describe here but the key steps are:
Drive is Not Spinning
If the drive is not spinning, most people assume it is dead. Usually, but not always. Sometimes you can get a dead drive working again by hitting it or dropping it. Freezing the drive sometimes works. Be certain you have no alternatives before trying these methods because they may destroy your drive! Prepare carefully in advance. You might only have one chance to succeed and you don't want to blow it.
Add your tips to make this a better quick guide to fixing common hardware problems.
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Howard Fosdick (President, FCI) is an independent consultant who supports databases and operating systems. He fixes old computers for fun and charity. Read his other articles here.