Computer Repairs

Buying a computer

Computers are now very powerful, there are many desktop pc’s that are as or more powerful than many of the servers I have repaired.

Even the most basic computer is capable of performing some very powerful tasks, buying the top of the range is not always necessary.

Computer Brand
Everyone knows Compaq, Hewlett Packard, Dell and IBM, these are some of the main personal computer manufacturers, buying a Compaq, Dell or any branded name means you have a reputable company behind the design of the computer, this used to mean a price tag to match, with the competition building computers the main manufacturers have brought down their prices to match some of the clone manufacturers.

Although some of the branded names use clone components at times normally the branded computer has a machine specific component, this being the motherboard, power supply etc, this is OK provided the computer is working or the computer is in warranty, as soon as the computer is out of warranty you are in a situation where in the event of a breakdown you can only buy the parts from the manufacturer or a manufacturer authorised supplier, this leaves them in a situation to control the price, should the price be too high you can only buy second hand or buy a new machine.

Clone Equipment
Clone computers are computers that are freely available to anyone, there are manufacturers normally in China and Taiwan that build components for computers, they sell these components through distributors in the UK and the rest of the world, any computer shop can buy these components and build their own machines badged with their own logo, if you buy a clone machine, when the warranty has expired you can take the computer anywhere to be repaired, any company can get replacement parts and there is no artificial price control.

Technology
I remember when the 486DX2 66 came out, we had one on the bench in our workshop and I went over to look in awe at the ultimate in power machine, these were £2000 plus (new) at auction and ridiculously high from branded manufacturers, I wondered how something so powerful could be reliable.
That 66Mhz machine is not powerful enough to run many of the modern scripts and programs today, we are now looking at speeds of 2Ghz plus, there are limits to the speed with current technology, these speed limitations are being minimised by fitting more than one CPU on a chip, duel and quad core, no doubt as technology advances there will be other ways emerging but at current technology 2ghz is about the normal maximum.

Things to consider
Unless you want a computer for a specific use there are very few things to take into consideration when buying a machine, even the most basic machine will serve as a powerful platform for a word processor, accounts package or games machine, some of the following things are things you may want to consider when looking around.

CPU
The fastest the better, there is often very little price difference between most speeds of CPU’s, then you will see a huge difference in the next level, this has always been the case, the top of the range is a lot dearer than the next one down, look at the current speeds and compare the prices buy the one that is the highest spec at the lowest price range.

Memory
Memory is cheap, buy as much as you can fit on the system board, when computers first came out the amount of memory that was directly usable was 640K and a hard disk of 40meg was huge, because of this programmers built programs that used little resources such as memory and disc space, Billy Gates brings out Microsoft Windows and the Bloatware was born, Windows demanded more memory the world memory companies supplied it and the price fell, the 640k memory limit was removed, hard drives increased in capacity programmers no longer needed to write small files and memory efficient programs, they could bloat out their programs knowing that the PC world would need to keep up.

Hard Disks
As with the CPU there is a specification level where the price goes up in a large step, my advice is to buy the largest capacity before the huge price increase.

Monitors
CRT monitors are heavy and bulky, LCD monitors are now cheap enough for anyone’s budget and should be a priority when purchasing, 17″ is fine but buy what suits your situation.

My mate can make a computer
This is a quote I have heard from many of my customers, if a friend says they can make a computer or they have a friend who can make a computer for you think twice and ask them the question, “Do they have an anti static workstation” if the answer is what is that or no then the chance of your computer lasting until old age is minimal, I ve seen on forums people saying “I made my computer on the carpet and it still works” it may or it may not but it wont last for long in most situations.

Bristol and Bath Computers
At Bristol and Bath Home Computers we do not actively sell computers, if requested by customers to make them one we will source the best value components and build the computer at our anti static workstation, we buy all components when required so you get the latest technology.

Cleaning a Keyboard

You may remember in my previous post about cleaning your computer system unit that cleaning your computer system unit can cause more harm than good, the same is true with keyboards.

Most computer keyboards are membrane keyboards, this can consist of two layers of plastic etched sheets and an insulating layer between the two, pressing a key pushes the contact on one layer of plastic through to the contact on the other through a hole in the insulating sheet, there are also rubber membrane keyboards that are rubber contacts that short across the contacts of the switch with carbon pads, gone are the days of the individual key switches.

The easiest and safest way to clean a keyboard is to turn it upside down and shake out the crumbs then turning it so the keys are facing you and shaking will make the crumbs fall out and not be collected by the key tops, a vacuum is a good option but you must make sure that the keys don’t fall off and get sucked inside, the miniature vacuums available for cleaning small places do not have enough suction to be any use cleaning a keyboard.

It is a good idea to avoid the use of air dusters, air dusters can cause the debris being flushed out to enter the membrane and stop the keys working.

A brush can be used to loosen the crumbs but extra care should be used to avoid moving the key tops and breaking or loosening the shaft.

There was a time when I would take a keyboard apart and clean every individual key switch, those days are way gone, the price of keyboards being so low doesn’t justify the time taken.

Finally a piece of damp cloth and a small amount of household soap can be used to clean the individual key tops, do each key top individually to avoid damaging the key top and stem.

The easiest way to clean a keyboard is to throw it away and buy a new one.

Cleaning a mouse

When you feel the mouse has a rough movement or the cursor doesn’t move up or down or left and right it is time to clean your mouse.

To clean an optical mouse couldn’t be easier, just blow the light under the mouse, if there is visible dust that doesn’t want to move the use of a soft cloth will normally shift it.

To clean a ball mouse it is still an easy job but a bit more fiddly, remove the ball by turning or pulling back the cover, there are normally arrows to show which way to open it, use a cloth to dust off the ball, look inside the ball hole and there is 2 rollers and 2 long shafts, the shafts control the up and down and the left and right movement and the rollers are there to steady the ball and to allow it to turn.

Using a blunt blade remove the material from the rollers and the shafts, try to remove the material from the mouse body, leaving it in there can cause a blockage to the light source and light censor, reassemble and use.

Link: http://milsom.biz

Before I proceed I just want to point out that this disaster recovery is a last resort after a major drinks spillage in your computer.

The worst disaster to a notebook computer is a drinks spillage, a drinks spillage can destroy a notebook computer in minutes, when I have been asked to do a repair quote for drinks spillage in the past I have quoted for every board that has been touched by the liquid.

All liquid spilt into a notebook will destroy the notebook very quickly but the worst and most common being tea, coffee, squash and I even had a hot chocolate once, add to any of those liquids sugar and milk and this is guaranteed death, there is however one chance and it is a remote chance of recovery and that is to give it a bath.

If you have a spillage of any type you need to determine the best plan of action, as soon as the spillage is noticed turn off the notebook, it may already be too late but turn it off immediately, remove all removable components, Batteries, DVD, hard disk, keyboard if it is an easy to remove one, inspect them to see if they are damp if so clean with a little water and dry immediately.

So now you have a shell of a computer with all components missing, this is where the scary bit starts, find out where the spillage was if it is in the keyboard and the lower part or the display, if it is just the lower part it is easier to clean because there are more openings,

Please bare in mind this is only as a last resort and the computer is not to be replaced as an insurance claim.

You need to put the computer under the tap and ensure that the water flushes out all the contaminant, if coffee, sugar or milk is left on the circuit boards they will corrode in hours, it must be flushed out while the contaminant is still wet, if the contaminant dries on the circuit boards it will not be possible to remove even after dismantling the machine, as soon as you have flushed out all the contaminant stand the notebook on its side on the radiator, ensure it doesn’t get too hot and damage the plastics but you need to dry it out as quickly as possible, even water can damage your notebook if left for a small length of time.

DO NOT SWITCH ON AGAIN UNTIL IT IS TOTALLY DRY.

When you are sure it has dried out connect up the power, turn on and hope for the best, it is unlikely that there will be no damage, the life of the machine will be reduced but you may get a few months or years more use out of it, if it works OK add the external components such as batteries, hard disks and removable keyboards and try again.

When I have repaired computers under a service agreement liquid spillage was not covered under the maintenance agreement and was always chargeable, the times I went in and the machine was dripping with liquid and the customer wasn’t sure what the problem was, many were surprised when I ask how they hadn’t noticed half a pint of lager in there, I wonder how they didn’t know.

I had to look at an IBM notebook for a major life insurance company, the notebook had been run over by a BMW and I was asked to access the damage, needless to say it was a right off as it was banana shaped, the amazing thing was it was still working, the screen was cracked and funny colours but he was still using it even though it rocked on his desk.

Please remember this is a last resort kill or cure remedy and may make things worse, this should not be used if there is a small amount of liquid in which case it should be looked at immediately by an engineer, dismantled and cleaned with solvents, we can carry out and emergency decontamination procedure for £85 this will include immediate collection and return to our workshop for chemical cleansing (subject to engineer availability).

Visit our main website to arrange a visit, for the immediate service you need to contact us by phone 0117 9071966 to ensure immediate deployment of our duty engineer, please ask for immediate cleaning service.

Dangers inside computers.

There are few obvious dangers inside a computer base unit, in fact as an engineer your main worry is not to you as the engineer/owner but to the computer, you may wish to read my anti-static post that I wrote earlier.

Inside the computer base unit are low voltage circuits normally having a max voltage of 12v DC, most of the circuitry is 5v and the 12v supply generally for external components such as hard disks and CDROM drives.

You can touch the 12 volt rail and not even know it was live, the main danger inside a computer box is the PSU (Power Supply Unit) this is normally a switched mode power supply and comes as a sealed unit within the computer, most of the computer builders of today put units together and very few if any understand the principle behind them, this is not such a bad thing because the insides of the PSU can prove lethal even when disconnected for a length of time and is best left to the professional, I am able to fault find PSU’s to component level but it is not worth the time.

Provided the PSU is not opened the only real obvious danger is the metal edges of the case, when I started building computers the quality of the cases were a bit suspect and razor sharp edges were the norm, it was normal to draw blood building a computer, nowadays the build quality of the computer cases has improved no end and you can safely work inside most computers and in fact all the computers we supply, writing this post takes me back to the first computer I built, it was a 286 at an amazing 25Mhz and I remember trying to make the board fit inside the case bending and squeezing case bits and the system board to make it fit, you modern day system builders don’t know your born with the Lego like construction.

Monitors are another very real danger, do not put a plant pot on top, when you water the plant and the water overflows sparks are very likely , burns and death is a real possibility and before you ask yes I did have a customer who did this (She lived), there are very high voltages inside the monitor, even after being switched off for a long length of time, I can repair monitors to component level but I will never take the back off on a customer site.

Most printers now have a PSU as a sealed unit, the main danger inside a printer is trapping hands or catching hair, these are normally prevented by a “chicken switch” sorry another college term, that kills the power when the lid is lifted.
I remember working on a laser printer, not sure I think it was either a Panasonic, Data Products or a Kyocera, it was on the bench and I turned it around to work on it, the side panel was off and I shorted out the PSU with my hand, the PSU was a board that had the circuit side outwards and I had an imprint of the circuit board on my hand in little white blobs, needless to say the PSU blew up and the manufacturer fitted a plastic cover on previous models.

I remember when I was at college in our components lecture the lecturer Mr Goodall (if you read this thanks), as we were studying transistors advised us a way to bump off our family members, we were studying Germanium and Silicon transistors, this is as Germanium were leaving the market as more reliable silicon were being built, he told us that one of the doping agents in the transistors was Arsenic and that we could dip a few transistors into our victims cup of tea and apparently the effects of arsenic are accumulative and eventually they would pop their clogs of arsenic poisoning.

I have no idea if this is the case and he was very obviously joking about terminating people but that does lead to the theory that if this potentially lethal component is used in old and modern electronic the disposal of all electronics components must be very carefully considered.

There are millions of electronic components out there and many millions are breaking every day, although the quantity of arsenic and many other poisonous elements are minuscule the accumulative level must be huge, Im sure Intel and Texas Instruments don’t buy these toxic elements by the cup, I am not an expert and I will not pretend to be but supposing all these elements in the land fill sides along with mercury, cadmium and other battery elements from disposed of batteries break free from their respective cases and enters the water table there is a recipe for disaster and mass poisonings.

When I looked deeply into this problem, not from books but just by looking at the amount of batteries disposed of from discarded McDonalads toys, computer boards and normal every day batteries I decided to not chuck my batteries and electronic items in the bin but get them disposed of properly, I guess the council consider the dangers when they build a land fill site but I am not prepared to put the future of my family and generations to come at the mercy of cash strapped councils, I could plead ignorance and take the cheap easy route or I could take responsibility for my actions and do my best to ensure the safety of the people around me.

You need to pay people to dispose of old equipment but it has got to be worth it as one small step to saving the earth.

I would appreciate comments from anyone who can highlight any dangers mentioned in my above post.

LCD (Liquid Crystal Display) monitors are different from the normal CRT (Cathode Ray Tube) monitors in the fact that the picture area is plastic as opposed to glass, we all know how much more durable glass is than plastic and that the CRT display can be cleaned by most household cleaners, provided there is no coating on the glass sometimes used to reduce glare there will be no problems.

Using a household cleaner on an LCD monitor can cause severe scratching and even cloud the display, the only remedy for this is to replace the whole monitor.
There are special chemicals cleaners to clean LCD monitors but these can be expensive and are totally unnecessary, the safest and cheapest way to clean an LCD monitor is with toilet tissue and water.

First get two pieces of toilet tissue wet one and wring out some of the water, it needs to be wet but not running to avoid water entering the display as it runs down the screen.
Apply a light pressure and quickly rub the damp paper over the whole area of the display.
Quickly before it dries use the dry piece of paper repeat and remove all the damp from the display, a very fast but light pressure movement works best.
You will have a nicely clean screen all over.
If there are persistent greasy stains such as finger prints you can add a small amount of household soap to the damp paper and repeat the above process.

In the event of a very stubborn mark or pen mark do not apply more pressure to the area, instead repeat the cleaning method above more regularly, there is a chance that pen can not be removed.

It is best to not touch LCD displays but the above process will safely remove any residue should visibility be impaired.

I have recently located this facility to aid the cleaning of your screen, please note this is not a total solution but should be treated as an aid, for more information please click here.

Disclaimer
I hate these but its got to be said.
I have performed this cleaning procedure on thousands of customers displays and never had any problems or caused any damage, we can not guarantee that the procedure will be followed correctly and not cause damage to the display, we supply this information at face value and can not be held responsible if any damage is caused.