The Basic Guide to

Scope of this book (what’s covered and what isn’t):

It’s not a guide to component level circuit board repair, but it does assume a few basic electronics tech skills such as the use of a DVM, oscilloscope, High Voltage probe, soldering iron, etc. If you don’t know what a Volt is, or how to set your oscilloscope to make a measurement, you won’t learn it here. If you do not know how to safely make voltage measurements, don’t do it. You run the very real risk of injuring the laptop or yourself. In particular, pay attention to high voltage measurements, as they can kill you dead.

In addition to basic electronics technician skills, the manual assumes that the technican has a thorough knowledge of the operating system and applications in use on the laptop / notebook. Without this, it is impossible to know whether a printing problem is a hardware or software one, whether a problem with the display is due to an incorrect video driver or broken cable, or whether the reason it won’t boot is due to a defective hard drive or a problem with the operating system on the hard drive. The typical laptop/notebook repair technician usually has 3-4 years experience as a desktop PC technician and a thorough understanding of the operating system on the unit.

This is a guide to the basic repair knowledge required to repair laptop computers. The terms laptop and notebook are used interchangably in this book. Technically they are different in that the laptop is larger than a notebook, which is 8.5"x11" or smaller. Units which are a lot smaller than 8.5"x11" are referred to as a sub-notebook computer.

Copyright Notice:

This document is copyrighted, just like a book. When you purchase a copy of this, you or anyone to whom you loan it are entitled to use the information contained within that copy. If you think something might happen to it, like the dog chewing it up, dropping it into the La Brea tar pits, or something even more hideous, make a copy for yourself. I don’t want to profit twice because of someone else’s misfortune.

On the other hand, buying a single copy does not entitle your friends to a copy, it does not mean that you can photocopy it and give a copy to each of the sales or service people in the shop, give your customers a copy, sell it at computer shows for $5.00, post it on the Internet, post it on an Intranet, hand out photocopies to students, or do anything which would allow more than one reader to view the document simultaneously. Even though technology allows you distribute information really easily, theft is theft.

We don’t incorporate copy protection into these documents because I don’t like it. It shows a distrust of my customers, and sometimes it just doesn’t work. However if I see it posted on the Internet or for sale at computer shows, future versions will ship in a strongly-encrypted format, generate a random number when the setup program is run, and require the user to call Thompson Publishing, nc. and register the software in order to obtain the pass phrase which corresponds to the random number. I don’t want this, honest users don’t want this, but as with many other things, one slacker out there could screw it up for everyone. So to try and prevent this from happening, I’ll offer a reward: If you know someone responsible for stealing or redistributing our products, call 1 (800) SPA-PIR8 (The Software Publishing Association piracy hotline) and dime the guy out. If you do, and he’s found to be guilty of stealing our products, you get one of every manual we write, even future titles, updates and new editions, shipped to your door, free of charge.

I spent a LOT of time writing this reference, which contains specialized information which isn’t easily obtained due to the limited marketplace, and if I can’t earn a modest profit for my tireless efforts, I won’t be writing or updating any more of these reference manuals. Since information about rapidly changing technology also changes rapidly, this information will soon be obsolete, and therefore outdated without being updated.

Bryan A. Thompson

Owner, Thompson Publishing, nc.

Educating the customer -

- before the unit is brought to the shop for repair (what’s necessary to be able to service the unit - AC power supply, external floppy, if any, special modem or network cables, if any, etc.)

- After the unit is diagnosed (what will fix the problem the customer cited, were any viruses found, any other problems such as partially cracked screen case or video cable, bad spots on the hard drive, stiff hinges that might need to be replaced in the future) - doing this in writing can keep the customer from expecting a warranty repair on something that wasn’t originally serviced. Maybe make a form that serves as a checklist reminder for the tech.

- When the unit is picked up - proper operation of the unit - how to open / close the screen, don’t use till it’s acclimated to the environment - 2+ hrs if hot or cold, or hdd damage could occur, don’t change docking bay. Maybe have stickers or forms printed that warn the user not to connect a PS/2 mouse while on, not to change docking bay modules while the unit is on, etc. Maybe put together a list of do’s and don’ts to send with the customer - may prevent problems in the future - how to extend the life of the battery - remove when running on AC power.

Environment for the tech -

Notebook are complicated, and the technician needs to concentrate entirely, so no distractions. No phone calls, questions from customers checking in or out, etc. until the thing is fixed.

Tools required for laptop/notebook computer repair:

A good set of miniature screwdrivers - get ones from Snap-On, the Craftsman and Radio Shack ones aren’t durable enough. Make sure to get sizes 1/8" - 1/4" flat blade and #00 - #2 Phillips.

Torx bit set - T4-T15 torx screws are very common in todays laptops, and you can’t buy them at the local home center. Best bet is to get a Jensen or Snap-On catalog and order them. If you try to use a flat-blade screwdriver or allen (Hex) keys to remove these things, they’ll mess up the screws or break.

Allen wrenches/keys/bits - These are hexagonal shaped bits. Sizes from .028" to 1/4" are useful in the repair of laptop computers. Again, buy good ones.

Pick / hook tool set - Snap-On makes a set of tools with hooks that are useful for getting into cases, removing and inserting video and KB cables. Probably the best investment in a tool for laptop repair I’ve made.

Plastic case opener - Compaq makes a special wedge-shaped plastic block used for opening their cases. It’s less likely to damage the case than a screwdriver.

A set of miniature pliers including side cutters, small and long needle nose, duckbill (for reshaping bent sheet metal parts), round jaws (for reshaping springs), and a set of miniature linesman pliers.

Set of small SAE and Metric nutdrivers - especially the 3/16" and 1/4" ones. These are useful for removing port connector standoffs.

Foreceps (also called hemostats) - curved and straight jaw (5" or 6") and a micro set (2" Birdnose) for smaller parts and as a soldering aid.

Hobby knife - Also known as an X-Acto (TM) knife - These are useful for precision cutting applications.

Telescoping magnet - good for reaching loose screws, paper clips, etc. Also good for starting smaller screws. It’s a good idea to keep these away from the floppy and hard drives.

Small flashlight - Useful for seeing into all those dark places, like the floppy drive, battery compartment, etc.

Needle file set - These are useful for smoothing rough edges, making clearance for larger hard drives, etc.

Digital Multimeter - Should be capable of measuring AC and DC voltage, AC/DC current and resistance, capacitance, and continuity testing. Don’t use the analog (needle) type, as they have relatively low in input impedance, and therefore present too much of a load on the circuit being tested.

High voltage probe - useful for testing the output of notebook inverter boards, which commonly reach 2KV. And read the instructions for using these things BEFORE you use it. High voltage can and will KILL YOU DEAD.

Neon AC (125V) voltage tester - can also be used for testing the HV output of notebook inverter boards. Don’t stand in a puddle of water when you use it, either.

Soldering Iron - Small, not one of those 300W Weller gun things. Should have a good selection of tips available, including very small ones for surface mount jobs.

Dremel tool - Good for removing broken screws, shaping broken plastic, etc. Also good for cleaning and polishing large electrical contacts like battery connectors.

2.5" - 3.5" hard drive mounting kit - Get two. These are useful for copying hard drives in a desktop PC. One is for the source drive, one is for the target drive.

Software useful for the repair of laptop/notebook computers:

Hardware diagnostics program - Such programs as Norton Diagnostics are capable of basic hardware testing.

DrivePro or Disk Manager - used for installing large hard drives in laptops without requiring a BIOS upgrade.

Internet Software and ISP account - In the past few years, this has become the most useful resource available to the repair technician. Device driver updates, software patches and updates, and conflict reports are just a few of the reasons an Internet account is useful here.

Microsoft TechNet - This is a collection of information produced by Microsoft that contains Microsoft’s Knowledge database. It has information about known conflicts with hardware and software devices and drivers, as well as specific info on those cryptic error messages displayed when the machine GPFs. Also information on specific Microsoft hardware and software products, like manuals, installation issues, patches, etc. Approx $250 / yr., but you get monthly upadtes to the CDs, so it’s well worth it.

Virus scanner - Preferrably one which boots with the operating system contained on the laptop hard drive. Viruses can appear to be problems with the hard drive controller or hard drive, video or floppy drive. Therefore it’s best to eliminate them as a possibility before going to the time and expense of opening the case.

Additional supplies for the repair of Laptop/Notebook computers:

Lysol in an aerosol can - Laptops are easily the nastiest things in the world to repair. People spill Coke in them, drop food crumbs into them, let their cats do unspeakable things to them, etc. Lysol cuts oil residue on the Keyboard and case, and just generally makes them safer and more pleasant to work on. Keep away from the LCD panel - some of these contain a clear plastic that becomes white when Lysol hits it.

Cyanoacrylate Adhesive (CA) - get the slow setting stuff along with an applicator bottle with small replaceable tips.

CA Accelerator in a spray bottle - good for curing this type glue when it’s applied really thick, like when used to fill a gap or hole, or to rebuild plastic that has broken. Be careful to lightly mist the super glue if it’s in a visible location, because applying a lot of the accelerator to the liquid adhesive will cause it to set extremely quickly, causing extreme heat which can melt plastic parts, and can also cause the plastic / glue joint to become weak and/or break. Curing too quickly can also cause the adhesive to become opaque (white) instead of clear in color, so try not to use it when the glue joint will be visible.

Solder - really small stuff with the flux built-in.

Solder braid / wick - This is a woven copper mesh used for pulling the solder away from a solder joint. Don’t touch it, as it oxidizes rapidly and will not work when oxidized.

Resin cleaner/ remover - This stuff, found in an aerosol can, is used to clean excess resin left after soldering a joint. It’s a good idea to clean the stuff, as it can, over time, eat the copper under it. It’s also messy and leaving it behind is a sign of unprofessionalism.

Compressed air - the big cans are usually cheaper, and make sure you get the little plastic straw that comes with these. This can also be substituted for component cooler for troubleshooting thermal problems.

Q-Tips - for cleaning hard-to-reach places. The ones with the long wood stick are useful for laptop repair.

Glass cleaner - while LCD panel covers are apart, it’s a good opportunity to clean around the edges of the panel. Use Windex brand stuff - some of the other citric acid based stuff (orange, grape, etc) can melt the protective plastic cover used on some panels.

Paper towels - again, for cleaning KB’s, cases, LCD panels.

Isopropyl Alcohol - get the 90% stuff, it’ll leave less residue when it dries. Good for cleaning floppy drive heads - use with Q-tips or chamois sticks. Keep away from the plastic plastic screen cover.

Cardboard - The thick corrugated kind. This is used to protect data cables while the laptop is in a disassembled state. This can also be used to protect the LCD display.

3M Scotch tape - This brand is preferred as it leaves no residue when it is removed.

When attempting the repair of any laptop, there are a few things that the technician needs to know. These include assessing the cost effectiveness of the repair, parts availability, and the skills of the technician. The first thing that should happen is to assess the problem. Regardless of the problem the customer reports, plug it in and turn it on. Run it through its paces, see what it does and what it doesn’t. This will give the tech a clearer picture of the actual problem and to determine any other problems the unit might have that require attention in addition to the one reported by the user. Be sure to test everything including the system board, memory, amount of memory, hard drive, floppy drive, video memory, cdrom, pcmcia ports, etc. Be especially sure to look for software problems. If the unit can be repaired without removing the case, the customer will be less likely to expect future repairs to be covered under the warranty provided by the first repair. Additional repairs are almost impossible to sell to a customer after the unit has been serviced, so be sure to inform the customer of any additional problems before the unit is serviced.

Another consideration when attempting a laptop repair is the relative skill level of the technician. Laptops are very fragile, and even more so when the technician is a notebook novice. The best way to learn laptop repair is to practice on relatively inexpensive units. 386's are a good way to start, as they are similar in size and construction to today’s Pentium and P2 laptops, and cost almost nothing on the second-hand market.

Another way to increase profitability when repairing laptops is to limit the make and models of notebook computers that you accept for repair to a few major manufacturers (IBM, Toshiba and Compaq), and then only to those models for which replacement components are readily available.

Laptop / Notebook computers are extremely specialized, so it is not practical to test individual components (other than the hard drive). A complete working unit is required to test such things as the LCD panel, audio card, keyboard, etc. This means that an educated guess is often required when repairing a unit which is brought in for repair “DOA”. Be sure to educate the customer that this may not be the only part required, but that it is necessary to troubleshoot the unit. If in doubt, overestimate the cost of the repair. A customer that receives a repair bill that is half that of the estimate will be much happier than one which receives a bill twice that of the estimate. In any case, be sure to evaluate the value of the unit, when working, on the used market. If it can be replaced cheaper than it can be repaired, it makes no sense to repair the unit.

General repair tips:

Disassembling the unit without damaging something:

REMOVE THE BATTERY AND AC POWER SUPPLY! Failure to do so will almost always result in damage to the unit or injury to the technician (remember the inverter board is capable of producing in excess of 2KV (2000 Volts). THIS CAN KILL YOU!

Be sure to detach the LCD panel from the CPU unit, including all cabling, before attempting to disassemble the case surrounding the LCD panel. If left on the CPU, the weight of the LCD panel can cause excessive stress on the top lid, breaking it at the point where it attaches to the hinges.

Those weird shaped screws:

Be sure that you use the proper size screwdriver for the screw. A flat blade or allen wrench is NOT a substitute for a Torx bit. An under- or oversized Phillips can strip a miniature screw, or damage the head to the point that it has to be drilled or cut out. Buying the proper tool almost always costs less than spending the time to do this, and to track down another screw to replace it.

Getting into the case:

Be very careful to remove ALL screws holding the plastic covers together. Laptop Manufacturers take great pride in their ability to hide these unsightly screws from the technician. They place them under adhesive plastic tabs, under the feet on the bottom of the unit, under keyboard overlays, behind port covers, in the battery compartment, under the removeable hard drive, etc. If you don’t get them all, attempting to remove the plastic will break it, and those plastic covers cost in excess of $100, if they’re available at all. Compaq is technician-friendly when it comes to disassembling the unit. They mark all screws necessary for removal of the case with an arrow with a double tail ( => ) and label one of them as “1 of X screws”.

Once you’re inside:

Be sure that you remember which size / length screw went where. Because of the multi-layer nature of today’s laptop, using a screw which is ever so slightly too long can cause components to become shorted. In the same light, be sure to take note of the order in which components, shielding covers, etc. are removed, so that they can be reinstalled in the correct order. Remember that reassembling a laptop is the equivalent of assembling a 3Dimensional, $2000, electronic jigsaw puzzle that, in most cases, isn’t yours. A video camera can be invaluable here for a before-during-after record of how things came apart and go back together. Just remember that the tape can be used against you in a court of law, so sit up straight and don’t slouch...

Those pesky plastic cables:

Once all the screws have been removed and the case is removed, be careful of those little flat plastic cables. In most instances, they’re not a press-fit, they’re a zero-insertion-force connector. The ends have to be released usually by moving a part of the end of the connector toward the center of the cable. In many cases, this cable release is a different color than the rest of the conector. Be very careful not to move the cable release too far, as they are easily broken. Remember also that there is a direction to these cables, and to be sure that the traces printed onto the cables line up with the contacts inside the connector. These are very common in today’s laptop, there are many varietys of these plastic cables, and they take practice to be able to properly remove and install them. I find that the pick tool set from Snap-On is particularly useful for this purpose. Never bend these cables to the point that they’re creased, and don’t try to solder a cable that has broken - they melt well before the solder does. Sometimes a conductive silver ink marker can be used to repair a weak spot, but nore often than not, a damaged cable will have to be replaced. The exception to the ZIF connector described above is the press-fit connector on the back of the floppy drive. Make very sure to line up both ends of this cable before inserting it into the connector, and be sure to press the connector straight into the connector, with no pressure whatever to the side of the connector. Make sure the cable enters the connector until the exposed silver part of the traces printed on the cable.

Storage of units under repair:

Lets face it - these are extremely fragile even when they’re together. Once you take off their protective armor, they’re even more easily damaged. And they take a long time to disassemble and to reassemble. This means that it’s not really practical to reassemble them while waiting for a part. Since parts are not always immediately available, it becomes necessary to protect the parts while you’re waiting for the part to arrive.

Try to keep small parts in a Ziplock bag, not a cup or even an antistatic bag. Make sure that it’s sealed.

Next, keep all static sensitive components in protective anti-static bags which are sealed on all sides. This includes the hard drive, floppy drive, motherboard, LCD panel, keyboard / trackball assembly, and any other circuit boards or components which are static sensitive. Not only do static sensitive components need to be placed in sealed static bags, each component should be placed in a separate sealed static bag. This is because when two or more components are placed in the same bag, the possibility exists for a metal part on one part, such as the case on a hard drive, to scratch a trace on another component in the bag, or worse, scratch the screen of the LCD panel.

Protect those flat plastic cables in all cases. Detach them at both ends from the components they connect, and using scotch tape (the 3M kind, as it leaves no residue when lifted), tape them between two pieces of thick corrugated cardboard.

Take every precaution to protect the LCD panel. They’re incredibly expensive, many times costing more than the complete unit. If you break the panel while it’s in your shop for repair, you might as well buy the customer a new unit - so be careful. Manufacturers ship them in antistatic bags, surrounded by 2" of high density foam, surrounded by thick cardboard boxes with ‘Fragile’ printed on the outside. If you have a few of these, keep them and use them to store the panel while it’s out of its protective plastic case. If not, tape it between three layers of thick corrugated cardboard which overhangs the panel by a couple of inches on all sides. Be sure to tape the high voltage cable to the side to prevent damage to the silicon insulation on it’s wires. In all cases, be sure to place the panel in an anti-static bag before using either method to store it. Storing the panel vertically in the plastic crate will help to keep anything from falling on it and damaging it.

The three types of batteries in the typical notebook computer:

The main system battery: This is rechargable and is the main source of power in a notebook computer when it isn’t being powered by the AC adapter. There are three main varieties of these:

- NiCd - Also called a Nicad or Nickel Cadmium. This is the oldest of the rechargeable battery types, and is typically good for about 1000 charges before is has to be replaced. There were no integrated electronics to measure the remaining charge in the battery, and only occasionally a circuit to protect the battery from overcharge. The voltage drops extremely quickly when its energy is expended, which afforded the user very little opportunity to shut the computer down before it was out of power completely. If the battery was not fully discharged before being recharged, it eventually develops a memory effect, limiting the amount of charge it would accept in the future. These were fairly inexpensive, but were very heavy, making them less desirable for the portable computer. Battery conditioners were used to recondition NiCd batteries, discharging and recharging them numerous times until they would again hold a full charge. If the battery was overcharged, as was often the case when the unit was operated from AC power with the battery installed, it was damaged beyond repair.

- NiMH/Nickel Metal Hydride - This is newer than the NiCd battery, and had a slightly higher energy density (power to weight/size ratio). Some batteries, known as Smart batteries, had electronics integrated into the battery and were capable of measuring the remaining charge, and therefore more able to prevent an overcharge of the battery. These were about twice as expensive as a NiCd battery, and has no memory effect, which meant that a half-full battery could be charged.

- Lithium Ion - This is the newest type of rechargable battery used for powering notebook computers, and is the lightest of the three. All contain electronics to measure remaining charge and prevent overcharge. These were also the most expensive of the three types, have the highest energy density of the three.

The Suspend battery - This is a rechargable battery, usually NiCd or NiMH, that stores information about the computer while it’s in a suspend state. This information allows the computer to be shut down and then restarted at a later date without requiring the system to reboot. When properly configured, all open applications and data are preserved during the suspend state. If the unit is not powered on for a week or so, the battery dies and the information is lost. This is why it’s a good idea to save all documents before placing the system in suspend mode.

The CMOS battery - This is a non-rechargable battery, typically Lithium, which maintains information about the computer hardware, date & time, when the power is turned off. This typically has a life of 3-5 years, but most are difficult to replace and if the unit is over a year old, it’s a good idea to replace the battery while it’s apart. They’re only about $10, far more than the labor cost to relpace the battery.

Troubleshooting screen (LCD) problems:

Important Note: Be sure to read the preceeding section on disassembling the unit safely before attempting any of the repairs recommended in this section.

Important Note: ALWAYS REMOVE THE BATTERY AND AC POWER SOURCE BEFORE ATTEMPTING ANY REPAIRS - Even if the unit is off, connecting the display panel to the CPU with power applied will damage the display.

Vertical lines:

Symptom: Usually a single line of a single color (Red, Green or Blue) in the top half or bottom half of the screen - This usually occurs on a unit with a dual-scan type display. This is indicative of defective video ram in the display. It is usually located on a PC board attached to the back of the display via a connector soldered to the board, or by flexible cables. Sometimes these can be replaced without requiring the entire display to be replaced. I’ve seen this problem with Toshiba T4700C’s and IBM 360CS/750CS notebooks. As long as the display is not physically damaged (cracked, cigarette burn on the screen, etc.), there are a number of repair organizations that can repair this problem much cheaper than the cost of a new panel. See the appendix for a list of these companies.

Display flickers -

This usually happens when the screen is moved relative to the base keyboard unit. This usually indicates a loose or broken video cable. These cables are almost always flat mylar with traces printed onto them, and breaks are usually, though not always, visible. Try reseating both ends of this cable (or sometimes two smaller cables), and if this does not fix the problem, replace the cable.

Vertical lines -

This will be repeated every 1/8" - 1/4" in the top or bottom half of the display. These are usually an absence of part of a text character, and are even more visible in a graphics screen (Windows). This usually indicates that the video data cable that connects the CPU to the LCD panel (almost always a flat mylar one with traces printed onto it) is loose or damaged. Try reseating the cable on both ends. If this doesn’t work, replace the cable.

Display dark -

Here text or pictures appear very dark, while still visible in bright light. Usually the power inverter board (the one marked ‘1000V’ or ‘Danger - High Voltage!’). It generates the high voltages necessary to drive the fluorescent lamps contained in the LCD panel, and is very susceptible to shorting on the protective aluminum shielding around the display.

Step one is to check the DC power to the inverter - Usually provided through the data cable or through a separate 3-4 wire power connector between the CPU and inverter board. If there’s no DC power to this board, it’s either the power cable or the power supply. Follow the power wires back to the logic board, and if there’s a DC voltage present, it’s the cable - replace it. If not, it’s the DC-DC power supply, either located on the main board or on a separate board with a bunch of transformers, inductors, and capacitors.

If you’re comfortable and know exactly what you’re doing, test the output of the inverter board (located in the LCD housing, with a couple of thick colored wires leading to the lamp in the display) using a high-voltage probe (your multimeter probably isn’t capable of measuring voltages this high, and can be damaged if used for this purpose, so don’t use it). Remember to keep one hand in your pocket at all times to minimize the risks of sending yourself into cardiac arrest (yes, this can happen, I’m not just saying this to sound like your mother or 7^th grade shop teacher).

If you’re not comfortable with this, there is another way to determine whether it’s working or not. Buy one of those $2 neon AC voltage testers, and place the test leads near the output of the large transformer located on the inverter board, near the HV connector that goes to the fluorescent lamps. If it glows, there is sufficient high voltage present to light the lamp.

If high voltage is present and the lamp is still not lit, then it’s probably broken or burned out. They are slender glass tubes coated with a white powder, and contain a small amount of Mercury, and as such, are hazardous material. Take precautions to prevent yourself from being cut (leather gloves, common sense, etc.), remove the tube, dispose of it properly and replace. Be sure that the Silicon insulation on the leads from the lamp to the inverter board are intact and not broken. If replacement lamps are not available, there are a number of organizations that can repair the display much cheaper than the price of a new display panel. See the appendix for a list of these companies.

A few randomly scattered dots -

They are usually red, green or blue, and more often happens on an active-matrix display panel. This is normal and extremely common. Each manufacturer has a different policy on the warranty replacement of these screens, and it usually involves the number, size and locations of these defective pixels. The reason that this happens is that the transistor matrix which controls which dot is on represents an extremely large number of transistors (1.44 Million, in the case of an 800x600 display) and the fact is that some have manufacturing defects, while others fail after the unit has been in service for a while. If the customer complains loudly enough while the unit is still under warranty, the manufacturer will usually replace it. The problem with this is that the new unit will have some defect as well, the dots are now in a different location, further aggravating the user, as well as the time the user does without the unit while it’s at the manufacturers repair depot.

Brightness or Contrast -

Changing the controls does nothing to affect the image displayed (and the image is bright enough to be seen) - There are three types of controls - slider or dial potentiometers on the LCD panel case, a combination of keypresses (like the Fn key and one of the other keys, like PgUp/PgDn or one of the number or Function number keys), and the software method of brightness/contrast adjustment.

If it’s the pot type, check the potentiometer (nothing more than a variable resistor). It’s probably in the 5K to 50K range, which means that the outside two leads read the max resistance, and somewhere in between when measured from the center lead to either of the outside two leads. Move the control to be sure that the first of these readings doesn’t change, and that the second one does. If the control is good, the Inverter board circuitry is probably defective. Replace the board.

If it’s the keypress type, run a basic diagnostic software program such as Norton Diagnostics, and test the keys to make sure the keyboard is good. If all the keypresses register in the diagnostic program, then the keyboard is good and the inverter board is defective. Replace it.

If you can’t find the controls, or if it’s the software type, it’s probably a Toshiba Pentium or newer, and of the active matrix variety. In this case, the contrast is controlled by the angle of the screen relative to the user, and the brightness is controlled by a utility in the Windows ‘Control panel’ section. If this doesn’t change the display, replace the inverter board. See the appendix for a list of these companies.

Large blocks of the screen are white, black, or a single color -

This sometimes happens when the display is cracked, or when it has a defective video ram module. If it’s cracked, it’s dead. No remanufacturer of displays will take it as a viable core for exchange, so if you want to fix it, find another defective unit with a good display, or purchase a new or remanufactured display. If it’s got a bad memory, there are a number of organizations that remanufacture or repair these LCD panels much cheaper than the price of a new unit. See appendix for a list of these.

No display -

This is a tough one. If there is no display, the first step is to see if the CPU unit is working, indicating a display problem, or if the problem lies in the CPU itself. Attach an external monitor to the unit and power on the unit. If there are lights on the CPU, and the hard drive spins up and starte to sound like the unit is booting, there should be an output at the VGA display port. Sometimes it’s necessary to press a combination of keys to get the VGA port to activate (usually a Fn key and one of the number or Function number keys marked with a picture of two displays, one which looks square and one which looks like a CRT tube). For example, IBM notebooks activate the VGA port while the video and memory self-tests are happening, then deactivate it unless it is manually activated by the keypresses, as a power saving feature.

If there’s no output at the VGA port, proceed to the CPU troubleshooting section.

If the display looks like what you should see on the LCD panel, then the problem lies in the display panel. Sometimes there is a screen-open sensor on one of the hinges or a pin sticking up through the top of the CPU unit. Check this switch to be sure it’s connected to the mainboard and that the switch works (a simple continuity test will suffice).

If the switch is good, connected and properly aligned, it’s probably in the DC power supply, the video data cable or the inverter board. Check for the presence of DC at the input to the inverter board, check for the presence of high voltage at the output of the inverter board, check to be sure that the contrast and brightness controls are set properly (not all the way up or down). If there’s high voltage present at the inverter board output, and the LCD panel lamp is lit, the problem is likely the video data cable. The problem could be due to a defective video driver board located in the CPU section, but if there is output to the VGA port, this is unlikely. Make sure the cable is tight on both ends, check for physical damage, and replace if necessary.

Noise (horizontal lines randomly spaced and / or moving) in the display -

First check to be sure the proper video driver is installed. This can be done by comparing the chipset type and model number of the video chip to the device driver description. Also check to be sure there are no screen centering TSR’s loaded, that the correct display type is selected in the system setup, and that the correct monitor type is selected in the ‘Display’ section.

Next, Make sure that the ground cable (sometimes a part of the video data cable) is firmly connected to both the LCD panel or inverter board and to the logic board. Without this ground plane, the panel cannot properly synchronize. Also check the integrity of any cable between the inverter board and the LCD panel, any cables that connect multiple boards on the rear or sides of the LCD panel. Make sure that the video data cable is properly seated on both ends, and that any connector contacts between the main logic board and video driver board are clean and free of oil.

Beyond this, look for a synch control (often a very small potentiometer or variable capacitor) on the LCD panel or inverter board. If it doesn’t seem to affect the output, check the output at the VGA port using an external monitor. If it shows similar noise, then it’s probably the video driver board, often a part of the main logic board. If the output at the VGA port looks normal, replace the video data cable.

Troubleshooting CPU problems:

Important Note: Be sure to read the preceeding section on disassembling the unit safely before attempting any of the repairs recommended in this section.

Important Note: Information in this section relates to the general repair of notebook / laptop CPU problems. For specific information relating to a specific model of laptop, refer to the ‘Getting into the BIOS’ and ‘Opening notebook / laptop cases’ sections.

No display -

If there is no display, the first step is to see if the CPU unit is working, indicating a display problem, or if the problem lies in the CPU itself. Attach an external monitor to the unit and power on the unit. If there are lights on the CPU, and the hard drive spins up and starte to sound like the unit is booting, there should be an output at the VGA display port. Sometimes it’s necessary to press a combination of keys to get the VGA port to activate (usually a Fn key and one of the number or Function number keys marked with a picture of two displays, one which looks square and one which looks like a CRT tube). For example, IBM notebooks activate the VGA port while the video and memory self-tests are happening, then deactivate it unless it is manually activated by the keypresses, as a power saving feature.

If there is a correct display at the VGA port, the problem lies in the LCD panel - see preceeding section on troubleshooting display problems.

If there is no output at the VGA port, the problem lies within the CPU / base unit. Sometimes a defective battery, PCMCIA card or ram module (all very commom problems) will cause a unit to not boot. Remove the items one by one, restart the laptop, and replace any items found to be defective. Make sure there are no loose screws inside the CPU case. This is a very common problem with laptops today.

Next test the AC power supply (the external box that connects between the wall and the computer). First test for the proper DC voltage and polarity, which should be indicated on the bottom of the power supply or bottom of the laptop, by setting the multimeter to the ‘DC Voltage’ setting and placing the leads across the output of the power supply. Next test for the presence of excessive AC voltage at the output of the supply. This is done in exactly the same manner as the DC voltage test, except that the multimeter is set to the ‘AC Voltage’ setting. The measurement should be very low, in the 10-100 mV range. If it’s higher, the AC module needs to be replaced.

If the AC input is correct (0-100mV), check the CMOS battery for proper voltage, usually in the 3V-3.6V range. It’s unlikely that this could cause the notebook to have no output (unless it’s a Macintosh), but it’s a good idea to replace those things every couple of years anyway, and while you’ve got it apart, it’s a good time. If they’re not replaced, they can leak and damage a logic board beyond repair. If the DC-DC converter (within the laptop) is separate from the main logic board, check to be sure that it’s connector is clean (use a pencil eraser or electrical contact cleaner that’s plastic-safe), that it’s seated properly, and that the ground screw is properly attached.

The next step is to remove internal components such as the hard drive, floppy drive, sound board, additional RAM modules, etc. one by one to determine if one of these components is the cause of the failure to boot. These items are unnecessary for the unit to produce a proper display, and can easily be eliminated as the source of failure, although this method of testing still does not guarantee that the component is good, only that it isn’t the (only) problem. In some systems (such as the Compaq LTE series) it is necessary to have the keyboard attached in order to turn on the unit. Be sure to check continuity at the KB connector to ensure the ‘on’ switch is functional.

If you’ve reached this point and the unit still will not power on, there is a problem on the motherboard. Check the solder connections on the power connector and those at the on/off switch. Check for bent or shorted pins in the PCMCIA, parallel, serial, docking station, and RAM expansion ports. If the CPU is socketed, check to be sure that it’s seated properly and that the protective insulators are intact. These are often mounted using plastic standoffs which can and do melt due to the tremendous heat generated by the processor, allowing the CPU leads to become shorted. If this happens, the motherboard is usually damaged beyond repair. I’ve found this to be a particular problem with the IBM 360CE and 755CX models.

Beyond this, the motherboard is defective. If your shop is not capable of board-level repair (very few are), then it can be sent to a board remanufacturer for repair. See the appendix for a list of these companies.

Keyboard / Trackball / Trackpoint errors -

Symptom: Some or all of the keys do not register as a keypress, or the trackball or trackpoint does not work. Use a diagnostics program capable of testing the keyboard, such as Norton Diagnostics, to test the keyboard. If it passes the keyboard test, and yet doesn’t register in some or all programs, scan for a virus. If it doesn’t pass the keyboard diagnostic test, try reseating the cables connecting the keyboard to the main board. If this doesn’t work, the keyboard probably needs to be replaced. Trackballs built into laptops often require cleaning with alcohol and Q-Tips. Also check to be sure the flat cable connecting the trackball or trackpoint is properly seated.

Port Errors -

Symptom: One or more ports do not work - External ports can sometimes be turned off in the system setup as a power saving feature. Check to be sure they are enabled and properly configured by using the hardware diagnostics utility software. External ports are easily damaged. If not properly aligned, pins can be pushed into the connector, or worse, connectors can be broken away from the motherboard, and docking station connectors are very easily damaged. PS/2 connectors are fairly standard and can sometimes be resoldered if the traces on the motherboard are still intact. If a PS/2 connector is attached to the motherboard and still doesn’t work, look for a fuse on the motherboard close to this connector. These sometimes appear as a small green resistor package or a white surface mount package marked 1A to 5A. Check it for continuity (a short) using the multimeter, and replace it if necessary. Also be sure to educate the user that the reason this happened was that a PS/2 mouse or KB was attached while the unit was on, and to be sure to turn off the power before connecting peripherals in the future.

Floppy read / write errors -

Symptom: The floppy does not work, or has read or write errors. Try cleaning the floppy drive heads using a cleaning disk or alcohol and Q-tip. If this doesn’t work, try reseating the floppy connector on both ends, and be sure that the BIOS is set to the proper type of floppy (usually a 1.44M, 3.5"). If this doesn’t work, replace the floppy. These are sometimes unavailable, and if this is the case, there are companies that specialize in the repair of notebook floppy drives. See the appendix for a list of these. On very rare occasions, a defective interface board (usually a board separate from the main logic board) can cause the floppy not to be seen at all. This is not a read error situation, but a ‘Not ready reading Drive A:’ error where the floppy never gets accessed, and no read light comes on. Replace the interface board and retest.

If a docking bay floppy, check for damage to the docking bay connector, and then check other docking bay peripherals. The main board on some notebooks can be damaged by removing or inserting a docking bay peripheral while the unit is turned on. If other components work in the docking bay, replace the floppy. Otherwise replace the main board.

CDROM drive error -

CDROM’s are usually a docking bay option, and many can be damaged by being removed or inserted while the unit is on. This is a particular problem with the Toshiba Satellite 1xx/2xx/3xx/4xx series, and damages both the CD and the main board, requiring the replacement of both.

CDROM will not eject -

There is a small solenoid inside the cdrom that ejects the tray. Clean the solenoid, test its coil for continuity, and clean the manual eject mechanism. Clean / check the docking bay connector.

Preventative Maintenance for the Notebook Computer

There are many steps the repair technician can take to prevent common future problems with the notebook computers which require very little time, and yet most can and will prevent future problems with the laptop. If a future failure happens within the warranty period for the last repair, the customer will almost always expect the repair to be covered by this, even if it happened in an area never touched by the technician. If this happens, try to explain that this isn’t covered by the warranty, as it is a separate failure from the original one. If there’s a chance that it happened because of the former repair, offer to waive the labor cost and repair the unit for the cost of the parts. For the above reasons, be sure to report to the customer any component that shows any sign of wear, even if the unit is functional. Give the customer the option of replacing the item when the unit is already disassembled. It will increase profitability, and save the customer money on future labor bills.

Clean the CD drive - Use canned air, open the device and hold it upside down so that any particles which are freed by the air can fall out of the device. This will prevent optics from being scratched by dust particles trapped between the disc and lens. Special lens cleaner discs are available if the lens is contaminated with oil residue (a fingerprint, for example).

Clean the Floppy drive - The floppy drive is the most susceptible component on the notebook computer when it comes to dust, dirt and debris. It’s a simple matter to clean the floppy drive - hold open the door, hold the unit upside down so that any particles that are dislodged, and use canned air to clean the unit. After this, use alcohol and a cotton swab to clean the read / write heads (both above and below the disk).

Check all the interconnect cables - These things work loose - especially the ones that connect between the motherboard and screen, and the ones between the keyboard and the motherboard. This is caused by opening and closing the screen or lifting the keyboard. Also check them for signs of wear at the hinge points - even though they work now, if they break during the warranty repair, the customer will likely expect the repair to be covered by the warranty. Here a little customer education can save a lot of bad faith on the part of the customer and profitability for the shop.

Make sure that ALL the screws are tight - These things work loose everywhere, and especially at the hinges. Tighten them all, whether you think they might be loose or not. Almost all the broken case repairs that I perform are due to loose hinge screws. The screws work loose, and the screen bezel breaks at the hinge point. If the customer continues to use the notebook, many times the video data cable is damaged. Cases are at least $100, if they’re available, and a video cable costs between $75 and $150. Another $50 for labor to replace it, and you’ve saved the customer over $300. Screws that are constantly coming loose can be secured in one of two ways - use a piece of a small rubber band passed through the hole in the hinge to keep the screw from coming loose, or place a small drop of CA adhesive on the end of the screw threads, then wipe most of the glue off with a paper towel. The remaining glue will act as a thread locker and prevent the screw from coming loose, yet allow the removal of the screw if necessary.

The reason it’s necessary to tighten all the screws is that some hold two boards together, and if they’re not tight, the connections to the board are loose. If the screw comes out of the hole and starts to rattle around inside the unit, it will most certainly short something. Four out of five notebook computers I service have loose hinge screws, and two out of the five rattle due to loose components.

Clean and lubricate the hinges - Dirty, and therefore tight, hinges are the second leading cause of screen case breakage. Always clean and lubricate them using a penetrating lubricant with Teflon, and make sure all the screws are tight, that the screen up.down switch is tight and connected to the motherboard.

Clean all the air vents and cooling fan - Today’s notebook computers generate tremendous heat due to increased LCD panel sizes and faster processors and faster hard drives. Clean all the air vents, even the ones covered with cloth to keep out the dust, and clean the cooling fan and surrounding components.

Reseat the expansion RAM card - If the unit contains a RAM expansion module, reseat it a couple of times to clean the contacts of any oxidation that might have occurred. These work loose from time to time and can cause the computer

Check the power connector - If the unit is disassembled far enough to allow inspection of the solder joints which hold the power connector to the power supply board and to the mainboard. They sometimes come loose and cause the unit not to charge the battery.

Clean the battery contacts - Use a soft cloth or pencil eraser to clean the contacts that connect the battery to the motherboard. Dirty contacts can decrease battery life.

Clean the keyboard - The keyboard is almost always full of hair, crumbs of food, paper clips, etc. While it’s apart is the only time is can be thoroughly cleaned. Use canned air, and hold it upside down so that any dislodged particles can fall out.

Clean the screen - While the screen bezel (plastic trim piece around the front) is removed is a good time to clean the screen. Use Windex and a very soft paper towel. It might prevent the user from damaging the screen by cleaning it with another cleaner, such as 409, which would damage the clear plastic protecting the screen.

Software - Preventative maintenance applies to the software as well as the hardware - Always check for viruses, run a thorough check with scandisk to check the integrity of the data and the free space on the hard drive, defragment the hard drive, and make sure there are no problems with the registry using Norton WinDoctor.

How to get into the system setup / BIOS / CMOS:

The CMOS contains information about the hardware contained in the computer, as well as information about the date, time and password. All systems are different here.

Some 386s and early 486s used a setup utility contained on a bootable floppy disk. Early Compaq units contained a diagnostics partition on the hard drive. Others are contained on an EPROM or FlashRAM chip contained on the motherboard, and require a sequence of keypresses to enter this program. Sometimes the system tells the user what this sequence of keypresses is before the system boots. Such a message would appear as: ‘Press <F2> to enter system setup”. Other times this message is suppressed to prevent the user from inadvertantly entering setup and changing something important. Try these few standard sequences first:

- If it’s a Compaq, chances are that a cursor will jump from the left corner to the right corner just before it boots, and if you press <F10> it will enter the setup mode.

- If it’s an IBM 486 or faster, press <F1> before you power on the unit.

- Look for an indication that setup can be entered on the keyboard, by pressing the ‘Fn’ key and another key, like ‘Setup’.

- Check for a message on the screen telling the user how to enter the setup utility.

Otherwise, while the machine is doing it’s self tests, and before it starts to boot, try the following key press combinations:

- Try pressing <CTRL>, <ALT> and <ESC> at the same time.

- Try presing <F2>.

- Try pressing <CTRL>, <ALT> and <INS(ert)> at the same time.

- Try pressing <CTRL>, <ALT> and the ‘S’ key.

- Try pressing <DEL(ete)>

If these don’t work, try checking the manufacturers website for a hint on getting into the setup.

Upgrades:

This section covers the most requested upgrades to notebook computers. Not many things can or need to be upgraded on the notebook computer, so I’ll start by listing the things that can’t be upgraded, or that don’t need to be upgraded on a laptop.

Things that can’t be upgraded:

The video RAM - The only reason that an increase in video memory is to allow a higher color palette (higher number of colors) or when an increase in resolution is desired. These things only apply to desktop computers, because on the notebook computer these specifications are fixed by the size of the LCD screen. It’s either 640x480 pixels, 800x600 pixels, or 1024x768 pixels. With an SVGA display, the resolution can be decreased, but when this happens, a black border around the screen, resulting in a smaller overall screen.

The CDROM - If the unit contains a CDROM, a faster drive usually isn’t available. This applies to upgrading the drive to a DVD drive as well. Unless the manufacturer or a third-party manufactures an upgrade to that particular model of laptop, it isn’t possible. If the unit didn’t come with a CDROM or docking bay for a CDROM, the only possibility is to add an external CD player: A PCMCIA model if the unit contains a free PCMCIA slot, or a parallel port model if it doesn’t. The PCMCIA unit is preferred as is can be powered by batteries. The parallel port model cannot.

The type of battery - This is determined by the design of the manufacturer. Units that came with a NiCd or NiMH battery contained electronics specific to the charging of that type of battery, and can’t be upgraded to a NiMH or Lithium Ion battery. A very few compaq’s contained batteries of the same shape in both NiCd and NiMH batteries. These units (Contura 4/25's and 4/33's) could use either type battery, as they contained electronics for the charging of both batteries.

The floppy drive - If the unit contains a low density drive, this can’t be upgraded to a 1.44 MB industry standard drive.

The PCMCIA / PC Card interface - If the unit contains a PCMCIA slot, it cannot use CardBus cards. If it does not contain a PCMCIA card slot, this can’t be added.

The cache RAM - Level 2 (L2) Cache RAM consumes a large amount of power, and produces a tremendous amount of heat. As a result, it was typically not included in earlier systems. With the introduction of newer battery and semiconductor technologies, adding cache RAM to a notebook computer becomes more practical. It greatly increases the speed (20-30%) of typical business applications. If it’s possible for a system to have an L2 cache, it’s already there and at it’s already at it’s maximum value.

Things that can (typically) be upgraded:

The main system RAM:

This is almost always a proprietary ram module, which is specific to one or two models of notebook computer. Be sure to get the one that applies to the specific model of notebook to be upgraded. Installation varies with the model and manufacture of notebook, but there are a few basic types of laptop RAM:

- The RAM Expansion slot -

This looks like a PCMCIA slot, except that the holes in the end of the card are arranged in rows and columns at a 45 degree angle to the edge of the card, whereas the rows and columns of pins on a PCMCIA card are parallel to the sides of the card. These are not interchangable, and will damage a PCMCIA slot if inserted. This can usually be added by the user, by disconnecting all power to the unit, including the main battery, and then inserting the card in the slot. Replace the battery into the unit, and turn it on. It will recognize that the memory size has changed, and either automatically reconfigure the BIOS or ask the user to do so manually. This involves entering the system setup and choosing the ‘Exit and Svae Changes’ option. When adding RAM to a system, it’s always a good idea to run a hardware diagnostics program to test the integrity of the new RAM.

- The RAM expansion module -

This is a circuit board with a bunch of RAM chips soldered to it, and includes a connector that matches the proprietary RAM expansion interface on the system motherboard. Check the system for a removable cover marked ‘RAM Expansion’ or with the RAM expansion symbol, which is a rectangle with a bunch of dashes coming out from two or four sides. Other times the system has to be completely disassembled so that the module can be installed, usually under the keyboard. Kingston modules include a lifetime warranty and almost always come with directions outlining the installation procedure. Again, remove the AC power and battery, disassemble the unit as far as is necessary to install the RAM, be sure that the connector is properly aligned before pushing it onto the motherboard, install the hold-down screw if necessary, and reassemble the unit. Power the unit on and it will recognize the change in RAM size and either automatically reconfigured the CMOS info, or give the user the option of reconfiguring it. In this case, enter the BIOS and choose the ‘Exit and save settings’ option, as no manual reconfiguration is necessary. Again, it’s a good idea to run a hardware diagnostics program to verify the integrity of the added RAM.

- The RAM expansion card -

These sometimes look like a very short SIMM or DIMM module, and if so, are installed much like a SIMM or DIMM on a desktop PC. These are usually found under a RAM expansion cover in the case, or beneath the keyboard in the case of IBM Pentium notebooks. Remove the battery, then install the card, reassemble the computer and power the unit on. The system will recognize that the amount of system RAM has increased, and either reconfigure the CMOS automatically or ask the user to enter system setup to reconfigure this value. Enter system setup and choose the ‘Exit and save settings’ option. It’s a good idea to run a hardware diagnostics utility to verify the integrity of the added RAM.

These were not designed as an upgrade for the system RAM, but rather as small non-volatile hard drives. They are capable of storing data for up to 100 years with no external source of power.