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COMMON PROBLEMS OF MOBILE CELL PHONES AND THEIR REPAIR.

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There is no doubt that dust is a major problem to all electronic equipments, the cell phone is no exception. The warning "keep in a clean, dry and safe place free from moisture" in most electronic devices buttress this point.Component rust and corrossion due to the presence of dust and moisture ladden air result in broken circuit and bridging of electronic wiring. This nuisance is well known to the cell phone repair engineer like in other electronin repair.Once the cell phone is dismantled, repair begin with the use of hot air from the rework station to fire ( solder down ) all components in the PCB in case some lost contact as a result of phone drop. Troubleshooting continue with the cleansing of the pcb including any other necessary part with methilated spirit/volatile liquid. For drying, hot air from the hot air station is used.It should be noted that resoldering must be done pribeing brushed off compleatly. In most cases the above is all that is required tobring the cell phone in question back to life.The common problems of cell phones are:(!)Power problem(2)Ringer problem(3)Vibrator problem(4)Ear piece problem(5)Keypad problem(6)Phone locked(7)Phone tripping off(8)Mouth piece problem(9)Mobile phone malfunction(10)Network problem(11)Charging problem(12)Screen problem

POWER PROBLEM: In this case the cell phone refuse topower on. (1)Check battery voltage and make sure it conform with manufacturers' specification (usually 3.7 volts) (2)Check and clean battery connector to PCB Make sure the connection is not damaged. (3)Charge the phone with aworking charger. If it charges the phone but phone do not power on, the power switch could be responsible. (4) Check power ic for burn, fuse and other components on PCB that concern power.(5)If all the components are ok, the problem could be software. The phone may be flashed with the appropriate fileRINGR PROBLEM:(1) Go to the setting menu and make sure the ringer option is turned on. Note that in some cell phones when headset is attached to phone, it will not ring through the speaker until you remove it. (2) Go to profile and make sure silent ,flight or online mode and the like that shut off volume is not activated. (3)Adjust the volume control of ringer. (4) Make sure call divert is not activated as this will take your calls to voice mail without ringing.(5)If all these are ok, check the ringer track for continuity using your multimeter. If not still ok, replace the ringer with a working one. If this does not solve the problem, there might be the need for a software update. Flash the cell phone with the appropriate flash file.

VIBRATOR PROBLEM: (1) Make sure that the vibrator is ok by connecting it to the ends of a battery. If ok, it shpuld vibrate. (2)Make sure that the vibrator is turned on from the setting menu. (3) Make sure that the vibrator contact the PCB. (4) Check the vibrator track for open circuit.

EAR PROBLEM : Make sure that the ear piece contact the PCB.92) Test the ear piece with a multimeter and make sure that it is ok. Put the ear piece in a working phone to be sure that it is good. Also replace the ear piece with a working one to know where the problem is. Clean the PCB with methilated spirit/volatile liquid and brush after soldering down all panel components with the aid of a rework station.A software problem is suspected if all these fails. Flash the phone with the appropriate flash file.

MOUTH PIECE PROBLEM: (1) Test the mouth piece to make sure that it is ok. (2) Make sure that the mouth piece make contact with the panel. (3)Clean the panel and the mouth piece to ensure that they are dust free. (4) Replace the mouth piece with a working one. (5) Check the mouth piece track to ensure that there is no open circuit.(6)Check the audio tracks Heat/solder the audio ic. (7) If all these fails,then a softwareproblem is suspected Flash the phone with the appropriate flash file.

KEYPAD PROBLEM:(1) Make surethat thereisno security device in place.You may need a code to dissable thekey lock. (2) Ensure proper contact of the keys with the PCB. (3)Make sure that the keypad s are not stucked .They should be able to move freely ie bounce up and down.(4) In some flip or sliding phones, there may be the need to remove the side scroll keys or /and the mouth piece for them to work. If the mouth piece is responssible, replace it. (5)Check the keypad track to make sure that there is no open circuit.

N.B. The next post will look at the remaining common problems, take a bird eye view of copmmon software problems, how to solve them and deal briefly with the common problems not listed here that are experienced by cell phone users including suggested solutions. And before summarising, we intend to look ata guides on how to possibly repair the camera,Radio, computer?,video,Television,Gun?,Players etc that are now being built into the cell phone to promote market.

N.B This article is divided into four posts. You can read the full article in the blog above. This is the first post.

All you need are the right tools and know-how to cleaning aluminum rims that are in these types of conditions.

Just by following these simple procedures you can quickly learn how to clean aluminum rims easily.

Corroded or oxidized aluminum rims can mean anything from just some sticky road grime and brake dust all the way to much more harsh damage such as pitting. The amount of time and effort that will be needed to clean them is primarily based on how severe the condition is. You need to be aware that oxygen is definitely one of the worst enemies for aluminum. Just by allowing your rims to be exposed to the air will result in them turning dull coloured, old and weathered. Moreover, people who live in colder climates and expose them to road salts damage them even quicker. Other culprits are grime, brake dust and other pollution contaminants. All these external factors can greatly affect the shine and lustre of your rim. So if you have invested into a brand new, or gently used, set of shiny rims you need to protect them from the air as much as possible.

To begin with, park your vehicle in a shaded area and take a garden hose and spray your rims with a strong steady stream of water. Then fill a bucket with lukewarm water and add a generous amount of liquid dish soap or other gentle rim cleaning liquid and mix thoroughly. Apply this mixture to each rim and let it soak for approximately five minutes and then hose it off with a pressurized stream of water. Take a good soft microfiber cloth or chamois and wipe them dry. This initial step alone should remove the majority of the surface grime and allow you to get closer to the actual corrosion and/or oxidization.

Mask off surrounding painted areas of your vehicle by utilizing some painter's masking tape and large sheets of plastic. After that, spray a layer of regular household oven cleaner on them and let it to soak in for about a half hour. Now take a pot and pan scrubber and scrub the entire rim thoroughly. When that is completed, take a hose and rinse it off right afterwards and then buff it dry with a clean cloth. For numerous types of corrosion and oxidization it is important that you repeat this process. A good point to know here is that sometimes that is all that is necessary to complete your cleaning job. If that is the case then all you need to do now is polish them with a professional aluminum brightener, which can be bought at any automotive store, and also polish them with regular car wax. However, if you find that it still does not completely fix the problem you will need to take more drastic steps.

This step will require you to apply a 400 grit sandpaper to all the pitted areas on your aluminum rims. For the majority of types of pitting this is basically the only do-it-yourself solution. Sanding can be accomplished by hand or, for much bigger areas, a motorized sanding wheel installed onto a drill can be used. If you do use this make sure you don't apply too much pressure and also be mindful to keep the wheel constantly moving in a circular motion so that you do not scrape too deeply into any one spot.

After they have been meticulously sanded to an even brightness you will then need to rinse them with a pressurized spray of water and polish them with aluminum brightener. Again you will need to wax your rims with some basic car wax to prevent further oxidation or corrosion.

Remember that you will need to clean aluminum rims on a consistent and frequent basis to keep corrosion and oxidization damage to an absolute minimum. When cleaning aluminum rims you will need to reapply a clear coat how to recondition old batteries of wax after each time, or alternatively, rub on a mild coating of oil on them to also prevent future oxidation or corrosion. The final most important thing to remember on how to clean aluminum rims properly is to always rinse them off and wipe them clean after driving in salted road conditions.