Power Cycling and other Maintenance Tips

(For Geeks Only)
By Joe Callison
16 August 2018

Most people are aware that many times a computer, modem or router problem can be resolved by just turning off the power to it, waiting a few seconds, and repowering it. This also works for all kinds of other equipment with electronic components, especially logic boards, in them. Sometimes even the power supply for a device has a protective circuit that must be power cycled to reset it. The following are some common experiences I have had that were fixed by power cycling.  

Laptops, Notebooks and Tablets:
Since laptops have batteries, turning off the power and even unplugging the charger does not remove all power from the laptop. If it will not start, then sometimes the battery must be removed from the laptop. If it has latches to release the battery for removal, it is an easy thing to do. Holding the power button down for several seconds after removing the battery is often advised to help discharge any remaining energy. If the laptop still will not start after reinstalling the battery, try removing the battery again and plug the charger in without the battery installed. If the laptop starts, then the battery is either too discharged or is faulty. If it is just too discharged, leaving it on the charger for several hours should resolve it. If the battery is faulty, you can remove it and run the laptop on the charger until a replacement battery is obtained.

If the battery is internal with no external access to remove it, then the device must be opened up to get to the battery cable connector. This should only be attempted by someone experienced at  disassembly or by carefully following either written disassembly instructions or videos on disassembly for the specific model of device. There are often screws hidden in various places and plastic latches that are very easy to break off, especially on plastic that is a few years old. Cable connectors should never be removed by pulling on the wires. Look for any connector latching mechanisms first. Sometimes it is a hinged flap on top of the long edge of the connector that lifts up, sometimes it is a plastic hook on one long side or on both short sides of the connector. Occasionally there are no latches. With the connector unlatched, use a preferably plastic tool to gently push on the connector to separate it. For a long connector, pushing a little near each end alternately will help get it started.

Recent Apple devices typically use adhesive tape strips instead of screws to held the devices together. These have to be slit with a special tool to prevent damaging internal components, and replacement adhesive tape for reassembly is not easily obtained.

Desktop Computers, Televisions, Video Players, Cable Boxes, other Entertainment Systems:
The power supplies in modern electronic devices supply a small amount of power to internal electronic components in order to sense when buttons are pressed or signals are received from remote controls. In order to completely power off the device, the power cord to the receptacle must be disconnected or the power strip, if used, can be turned off. Some devices still have a two-position on/off switch on them, possibly on the rear of the device, to disconnect the power.

Sometimes a remote quits functioning and often replacing the batteries will fix it, but it is possible the batteries were good, and cycling the power is what actually fixed it. You can try removing one battery, waiting a few seconds, and then reinstalling the battery to see if it works before replacing the batteries.

Printers, Scanners, and All-in-Ones:
These devices typically supply power to buttons or control panels even when they are turned off using the buttons or control panels. There is often a two-position on/off switch somewhere on the device to shut down all power, otherwise, the power cord must be disconnected. Some have an external power adapter that may have protective circuits that can shut down and have to be power cycled in order to be reset. HP in particular has done this on some models. The cables between the device and power adapter and the power adapter to the receptacle must both be disconnected, wait 30 seconds, and then reconnect them.

More and more appliances have embedded logic boards or microcomputers in them these days. If it has digital readouts or LCD panels, then you know it does for sure. While I have not yet experienced needing to cycle the power on an appliance, it is only logical that it could freeze up like any other computerized device and need it. Like other devices, unless it has a two-position on/off switch to disconnect the power, then the power cord must be unplugged to cycle the power.

Appliances with motors may have additional motor protective devices that when actuated may automatically reset, have a manual reset, or have a protective component that must be replaced in order for the motor to run again. The appliance should always be unplugged from the electrical receptacle before doing anything around the motor power circuits. Be cautious of motor starting capacitors or power supply filter capacitors that may still have a high voltage charge remaining even after removing the power.

Posted by Joe Callison

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