PC Diagnostic, Testing, Maintenance and Tools - Prashant Serai

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PC Diagnostic, Testing, Maintenance and Tools.

1Prashant Serai, P14, V.E.S.P

Preventive MaintenanceNo matter how good the configuration of your PC may be, if you don’t take care of it, it is bound to slow down soon and gradually drift towards failure. Just like all other appliances you own, it is essential for you to perform regular preventive maintenance of your PC.


Preventive Maintenance The measures taken to keep equipment working and/or

extend the life of the equipment is called Preventive Maintenance (PM).

It is named so because, the measures taken prevent the failure before it actually occurs.

By Ensuring Long Life for your PC, it reduces the chances of Problem Behavior and undesired Data Loss.

There are two types of PM, Active PM, Passive PM and Periodic PM.

Active PM basically involves measures like periodic cleaning of the system and its components

Passive PM involves steps to protect the system and its components from the environment

Periodic PM includes few tasks the user must perform after certain intervals say weekly, monthly, etc. 3Prashant Serai, P14, V.E.S.P

Active Preventive Maintenance

It may interest you that, lesser the Passive PM you do, more the amount of Active PM you have to do, and vice versa.

When not cleaned for a long time minute foreign bodies particularly dust gets accumulated inside various components of the PC like the CPU, Keyboard, Printer, etc.

This can become a cause of improper operation of the particular component.

Also, Dust acts as a thermal insulator, this prevents proper system cooling. Excessive heat reduces the component’s life.

A regular cleaning of the system removes any layers of dust & foreign particles. Thus, keeping the above problems at bay.

The tools which could be used for Active PM include Wrist Grounding Strap, Air Blowers, Eraser, Canned Air, Small Brushes, Foam Tape wid solutions like Acetone, Isopropyl Alcohol, Trichloroethane, Freon,etc.


Passive Preventive Maintenance

Passive Preventive Maintenance involves taking care of the system from physical environment and electrical problems.

Physical Conditions such as temperature, thermal stress from power cycling, dust, and air pollution, and disturbances such as shock and vibration.

Electrical Problems are things such as Mains Fluctuations (use UPS), Power Line Noise (use RFC), ESD and RFI.

Thermal expansion and contraction from excessive temperature changes place stress on the components of computer system. So, to provide the computer the right temperature, one must choose cooling/heating solutions depending on the ambient temperature of that area.

For preventing dust and air pollution it is advised to have air con in the computer room, and AVOID smoking near the PC.

Never allow any PC component to get subjected to shocks or vibration especially when it is ‘ON’. 5Prashant Serai, P14, V.E.S.P


Periodic Maintenance Procedure

Periodic Maintenance includes few tasks the user must perform after certain fixed intervals of time.

Tasks to be Performed Weekly: Check for and install antivirus updates. Defragment the Hard Disk. Delete all Temporary Files such as *.temp, ~*.*, *.chk Empty the Recycle Bin. Backup Important Data onto the internet, pen drive etc. Tasks to be Performed Monthly: Create System Restore Point. Check for and install any Operating system updates. Check whether everything is working properly and in good

condition.


Preventive Maintenance of HDD

Take backup and format the HDD at least once a year and reinstall all software to maintain disk efficiency and speed.

Format the drive in the position and at the temperature it will be used.

Make periodic backup of your data and critical areas, such as MBR, VBR, FAT, and root directory on the disk.

Provide good surge protection (Spike Guard) or UPS. Do not keep HDD or CPU near the vibration area. Ensure fitting of HDD, that the disk is fully secured and

well supported in the CPU cabinet.


Preventive Maintenance of Monitor

Switch off the monitor before switching off the mains.

Before switching on the mains ensure that power switch of the monitor is in the off position.

Use dust cover for monitor when it is off. Regularly, Clean the display screen without allowing

any water to go in. Do not put monitor near strong magnetic field,

which may cause improper deflection. Provide proper ventilation for heat dissipation to

avoid intermittent failures. DO NOT PUT paper or any thing else on top of the

monitor.



Preventive Maintenance of Keyboard

Press the keys gently and do not rest your hands on the keyboard.

Don’t keep anything on the keyboard. Don’t play with the keyboard after powering off the

system. Don’t spill any liquids on the keyboard. Use dust cover for keyboard when not in use. Clean interior of keyboard with a miniature vacuum

cleaner or turn it upside down to blow out the dirt. Clean conducting parts of keyboard with denatured

alcohol and lint free material Make sure that the cable is not subjected to high

stress at the keyboard end else the signal wires might snap.




Preventive Maintenance of Printer

Use dust cover for printer when not in use. Clean the exterior of printer of printer using soft cloth

with mild organic solvent. Clean out dust, paper fragments and dirt from its

mechanism using soft brush. Check that the paper feed path is free of obstructions. Clean the paper feed path, platen and ribbon path (in dot

matrix type) with soft cloth. Lubricate mechanical parts. Use quality ribbon to avoid damage to print head. Don’t place the printer close to any heat generating

machine such as heater, fire place, etc.



Keyboard - Problems and Causes

o Complete non-operation: Broken connection, Keyboard lock is not unlocked, problem with keyboard socket.

o Wrong Characters Displayed: Bad Keyboard cable, Problem with row decoder or column decode logic, misalignment of sheets (if membrane type).

o One or Few keys don’t work: Keys are bad, Dust accumulation, Broken contacts, dry soldering, loose contact, etc. on circuit board.

o Unwanted Repeat Action: Bad key, Bad interfacing cable, Bad keyboard Controller.

o Characters remain in upper or lower case: Bad caps lock key, bad shift key, bad keyboard controller.

o Key being sticky or difficult to press: Accumulation of dirt.


Mouse - Problems and Causes

o Mouse not working: Bad mouse cable, problem with mouse port, IRQ Conflicts, Motherboard Malfunction.

o Mouse works only in particular directions: Wrong software setup, Dust Accumulation, Fault in one set of roller sensors.

o One or Few Buttons don’t work: Buttons are bad, Dust accumulation, Broken contacts, Dry soldering.

o Mouse movement bumpy, irregular or uneven: Excessive accumulation of foreign particles inside the mouse, Wrong setup of driver, improper configuration settings such as pointer speed, mouse acceleration, etc.


Electrostatic Discharge (ESD) Electrostatic discharge (ESD) is the sudden and

momentary electric current that flows between two objects at different electrical potentials. The term is usually used to describe momentary unwanted currents that may cause damage to electronic equipment (pc components).

Our body accumulates static charges up to 25,000 Volts! They look for a discharging path offering shortest resistance. The body offers considerable resistance, so they don’t

discharge through it. But when we comes into contact with any electronic equipment, its circuitry often provides a very low resistance path to ground, so a heavy discharging current flows, which may damage the equipment.

Protection Measures: Earthing, wear ground strap on wrist, put anti-static mat near pc, anti-static protective tubes & bags, periodically touch unpainted metal, handle ics without touching their pins, initially touch a grounded area. 18Prashant Serai, P14, V.E.S.P


Radio Frequency Interference(RFI)

The unintended reception of RF waves leads to a phenomenon known as RFI. Nearly every electronic device is subject to radio frequency (RF) interference from external sources if inadequately shielded, designed, or otherwise configured to be compatible (use of RFCs).

The RFI is caused due to a source of RF transmission near PC. Interference of 10khz + radiations is termed as RFI.

The sources which could cause RFI are: - Cell Phones -Cordless Phones- Motors -High Speed Digital Circuits- Television Reciever- Wireless PC Peripherals (keyboard, mouse,etc.)- Power Line Communication.



Logic Probe. A logic probe is a hand-held pen-like probe used for

analyzing and troubleshooting the logical states (boolean 0 or 1) of a digital circuit.

It can be used on either TTL (transistor-transistor logic) or CMOS (complementary metallic oxide semiconductor) integrated circuit devices.

In digital circuits many signals oscillate very rapidly, so the simple voltmeter becomes useless. So, for testing and troubleshooting them, we use a logic probe.

The pulse detecting electronics usually has a "pulse stretcher" circuit so that even very short pulses become visible.

There are usually 3 different LEDs on the probe's chassis; A red and green LED indicate high and low states respectively, An amber LED indicates a pulse.

Using the probe we can determine whether the clock circuit is operating & whether other signals are present or not.

Logic probes can monitor only 1 line at a time. 22Prashant Serai, P14, V.E.S.P

Block Diagram of Logic Probe

Vref

I/p

Pulse

I/p

Comparator

Pulse Detector

& Stretcher

Amplifier

Red (High)

Green (Low)

Amber (Pulse)



Logic Pulsar.

It is used to inject pulses into a digital circuit and even for applying particular logic levels.

It is used to test circuit reaction to particular logic levels applied at particular points.

Logic probe and pulser are generally used together to test ICs by verifying the truth table.

Example: Inverter testing It has a unique ability to introduce a changing signal into

circuit without breaking any tracks or desoldering anything.


Block Diagram of Logic Pulser

O/p

+5V

Gnd

Pulse

GeneratorMultivibrator

O/p

Stage



Current Tracer

Current tracer is a device having special ability to check whether current is flowing in a particular branch without altering the circuit conditions.

It works on the principle of electromagnetic induction.

It has a coil in it, which gets induced with emf by the magnetic field, which gets produced due to the flow of current.

It is useful in locating shorted components, track shorts, etc.

In the figure, we want to check whether gate B has shorted inputs.

The line is pulsed using the Logic Pulser, if the input is ground then heavy current will flow which will be sensed by current tracer and its LED will glow.



End of Presentation.


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PC Diagnostic, Testing, Maintenance and Tools - Prashant Serai