Disassembly safety: Difference between revisions
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Before you start a [[Disassembly|disassembly]], there are some things you should know. |
Before you start a [[Disassembly|disassembly]], there are some things you should know. |
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'''Eye damage.''' |
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There is a risk of damage to your eyes due to small pieces of metal or plastic breaking loose -- releasing due to force stored during manufacturing, or structural stress. |
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:'''Controls''': protect your eyes. Eyeglasses will help; safety goggles (sports or industrial) are better. |
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'''Static discharge.''' |
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'''Static discharge.''' There is a risk of damage to the system if you touch electronic components. You might well not necessarily feel the discharge for it to do damage. The damage is not necessarily immediate, the system can fail some months later, or even not work reliably. The damage can be cumulative. '''Solution''': Make sure you and the laptop are at the same potential before dismantling. Touch a hinge screw. Ideally, your work area should be conductive. Connection (through a current limiting resistor) to an earth ground is desirable, but optional. When returning to the workstation, touch the conductive mat (or the hinge screw) first. |
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There is a risk of damage to the system if you touch electronic components. You might well not necessarily feel the discharge for it to do damage. Synthetic fabrics rubbing against some other insulating materials can charge you to many tens of kilovolts. According to Hewlett-Packard's Bench Briefs some years ago, if the static charge on your body is less than about three thousand volts, you won't feel the sudden discharge when you connect to ground. Modern electronics can be damaged or destroyed by 100 volts in some instances. The damage is not necessarily immediate, the system can fail some months later, or even not work reliably. The damage can be cumulative. |
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:'''Controls''': Make sure you and the laptop are at the same potential before dismantling. Touch a hinge screw. Ideally, your work area should be conductive. Connection (through a current limiting resistor) to an earth ground is desirable, but optional. When returning to the workstation, touch the conductive mat (or the hinge screw) first. Get, and use, a wrist grounding strap! They cost only a few $US, and include a safety resistor to protect you if you touch the AC mains (line) voltage. Static problems are worse in dry climates and during cold winters when the indoor air is not humidified. |
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'''Shorting.''' |
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There is low risk of electric shock, since low voltages are used inside the system. However, there is a risk of accidental shorting with tools or screws. There will remain a clock battery (a "coin cell") on the main circuit board, powering a small number of circuits. |
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:'''Controls''': Remove the main battery and the power cable before starting disassembly. See [[Fix_Clock|Fix Clock]] before removing the clock battery. |
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'''Impact to motherboard.''' |
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It's both delicate and costly |
It's both delicate and costly. The components used are small enough that dropping a screwdriver on the board may knock off vital components. Many connections are so close together that a tiny metal chip, too small to easily notice, could create a short circuit which might simply make the motherboard not work, or damage it, when you reconnect power. |
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:'''Controls''': Be careful with the motherboard. Do not drop the motherboard. Do not drop metal objects on the motherboard. Cover motherboards with antistatic padded bags when they are not in laptops. See [[Motherboard Handling Procedures]]. |
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[[Category:Repair]] |
[[Category:Repair]] |
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Latest revision as of 04:59, 6 August 2013
Before you start a disassembly, there are some things you should know.
Eye damage. There is a risk of damage to your eyes due to small pieces of metal or plastic breaking loose -- releasing due to force stored during manufacturing, or structural stress.
- Controls: protect your eyes. Eyeglasses will help; safety goggles (sports or industrial) are better.
Static discharge. There is a risk of damage to the system if you touch electronic components. You might well not necessarily feel the discharge for it to do damage. Synthetic fabrics rubbing against some other insulating materials can charge you to many tens of kilovolts. According to Hewlett-Packard's Bench Briefs some years ago, if the static charge on your body is less than about three thousand volts, you won't feel the sudden discharge when you connect to ground. Modern electronics can be damaged or destroyed by 100 volts in some instances. The damage is not necessarily immediate, the system can fail some months later, or even not work reliably. The damage can be cumulative.
- Controls: Make sure you and the laptop are at the same potential before dismantling. Touch a hinge screw. Ideally, your work area should be conductive. Connection (through a current limiting resistor) to an earth ground is desirable, but optional. When returning to the workstation, touch the conductive mat (or the hinge screw) first. Get, and use, a wrist grounding strap! They cost only a few $US, and include a safety resistor to protect you if you touch the AC mains (line) voltage. Static problems are worse in dry climates and during cold winters when the indoor air is not humidified.
Shorting. There is low risk of electric shock, since low voltages are used inside the system. However, there is a risk of accidental shorting with tools or screws. There will remain a clock battery (a "coin cell") on the main circuit board, powering a small number of circuits.
- Controls: Remove the main battery and the power cable before starting disassembly. See Fix Clock before removing the clock battery.
Impact to motherboard. It's both delicate and costly. The components used are small enough that dropping a screwdriver on the board may knock off vital components. Many connections are so close together that a tiny metal chip, too small to easily notice, could create a short circuit which might simply make the motherboard not work, or damage it, when you reconnect power.
- Controls: Be careful with the motherboard. Do not drop the motherboard. Do not drop metal objects on the motherboard. Cover motherboards with antistatic padded bags when they are not in laptops. See Motherboard Handling Procedures.