BIOS VIII: troubleshooting: Devices misidentified

SYMPTOM
Devices misidentified

Probable Cause:
BIOS is incorrectly configured

Solution:
Use BIOS setup to reconfigure device options in BIOS

Motherboard III : Troubleshooting - Bad CMOS battery

CMOS stores configuration data when PC is off. This is thanks to a battery backup connected to the mobo. Older modelsit's soldered in, but more recently this held by clips.

Motherboard II: Installations

You typically install motherboards due to

• Mfg defects
• Rough handling
• Upgrading a PC
• Building a PC from scratch.
  

Mobos normally are held in place either by screws or plastic clips; have to open both sides of the case to access them.

Installation of a mobo:

• Unplug PC and open the case (observing normal safety precautions)
• Disconnect wires, cable, connectors from the old mobo in the case
• Remove the power supply and drives from the system if they are in the way of removing the mobo
• Unscrew the mobo from the case (or release the clips)
• Store the old mobo in a static-safe bag or box
• Install the new mobo and secure it.
• Reinstall the necessary wires, cables, and connectors
• Close, reconnect the cables and boot the PC
  

CPU I: Installation

• CPUs rarely fail by themselves - normally it is a mobo part.
  
• Typically, you don't upgrade a PC by replacing the CPU; you will normally replace the whole mobo
• If it happens that you do replace it on the mobo, you must match the CPU to the mobo

Installing one:
CPU pkgs are held in their sockets on the mobo by retaining clips or locking levers (older models).

1. Unplug the PC and open the case (observe normal precautions)]
2. If needed, remove the old CPU by releasing its retaining mechs and lifting the CPu from its socket.
3. Place the old CPU in an appropriate box or static-safe bag
4. Insert the new CPU into the socket and secure it with the retaining mechs
5. Close the case, reconnect cable, boot the PC.
   

If also installing a mobo and a CPU at the same time, install the CPU on the mobo before installing the mobo in the case.

PC Cooling issues

The current crop of P4 CPUs (except the "M" class) use over 100 watts of power. In fact, they generate more heat than a kitchen hot plate.

Intel specifies that the internal temps of the case should remain near 40 Centigrade.

Typical cooling mechanism is to force hot air out of the case with a fan, allowing cooler air to enter.

Modern cases include multiple openings for air flow.

Fans alone aren't enough, so modern PCs have heat sinks that "absorb and dissipate heat produced by electrical components."
Cooling Fins that transfer heat away from CPU. Rely on convection (warm air rising away)

Heat Pipes - small tubes filled with fluid that expand and rise to a different area for cooling. (No pump needed).

Water pumps - typically just for gaming PCs.

Peltier coolers - different mechanism than convective coolers (which won't work when the outside air is warmer that the air inside the case).

BIOS VII: Recovering from a failed BIOS update

Options for recovering from a failed BIOS update:

• Use the backup created by the flash util to restore the previous version
• Have an emergency floppy disk on hand that includes the "boot block" section of your BIOS. This has sufficient support to boot your PC from the floppy. No video is displayed. Once the PC has booted from the floppy and copied the correct BIOS over the corrupts one, reboot your PC.
• Flash Recovery Jumper Switch: Some mfgs include one of these on the mobo. You set the switch to the recovery position, insert the system upgrd into the drive and reboot. The system will boot from the disk and copy original BIOS over the corrupted one. Reset the jumper switch back to normal and reboot again.
• If none of the above work, will might need to replace the BIOS chip with a new one from your mfg.

Here's another source of advice from technibble

How To Recover From A Bad BIOS Update

BIOS VI: BIOS update failures (cautions)

Cautions for the BIOS update process:

• Don't update BIOS unless you must.
• Never turn off the PC in the middle of a BIOS upd.
  
• Make sure that power doesn't go off in the middle of an upd. (ie, UPS)
• Do not press Ctrl+Alt+Del during the update.
• Make sure you have the correct BIOS Flash utility from your PC mfgs web site
• Follow the flash utilities instructions exactly.
• Be sure you have the right version for your operating system, since flash utils typically only work with one version of Windows.
  
• Make sure you back up your BIOS before updating. (Most flash utils offer this option.)
  

BIOS V: Flashing the BIOS

This will depends on your getting an executable from the PC mfg.

1. Use the System Information tool(or MSINFO32) to determine your current BIOS version.
   
2. Visit the mfgs web site support pages to locate their BIOS update files. Compare their version # and release date with the info from the System Information tool to see if a new BIOS version is available.
   
3. Download the new BIOS installation executable.
   
4. If it isn't part of the installation pkg, also download the "flashing utility" from the website.
   
5. Close all open applications
6. Open and run the flashing utility and follow its instructions.
   
7. Restart PC when prompted.
   

BIOS IV: Version determination

MSINFO32 run cmd

Or
Start -> Programs -> Accessories -> System Tools -> System Information

• Record the value listed in the BIOS version
• Record the value listed in the SMBIOS field. SMBIOS is used by PC inventory pgms to collect data about your PC. (Not all PCs include this).

BIOS III: Updates

Normally the BIOS that ships with the PC is all you need. But sometimes you might need updates.

• You have device problems or bugs that your PC mfg identifies as BIOS based.
• You have device problems that seem to have no other cause than the BIOS, and you have exhausted all other avenues.
• You need to use new hardware options that are supported by your mobo but are NOt supported by BIOS.

The BIOS mfgs do not provide updates to consumers. They provide the BIOS to the mfgs in an incomplete state. The PC mfgs make the final mods and tailor the BIOS to their hardware. This "tailored" BIOS is what you get.

BIOS II: Upgrades

The BIOS is provided in a form of memory chip (EEPROM) that does not lose its contents when the power is turned off. A BIOS can either in a ROM chip or a flash memory (EEPROM).

ROM based BIOS is programmed at the factory. It can't be changed without replacing the chip.

Flash-memory BIOS can be updated using a special program provided by the mfg.

"Flashing The Bios"

BIOS I: definition

Basic Input/Output system

A set of software instructions stored on a chip on the mobo

The BIOS enable basic computer functions such as

• getting input from the keyboard
• getting input from the mouse
• getting input from the serial ports
• etc

A mobo mfg will select a BIOS and integrate it into the board.

Answers.com basic entry for BIOS

Power Supply Trouble Shooting: PC fails to boot but fans startt

Symptom:
PC fails to boot, but fans start.

Probable cause:

• Power connector to mobo not hooked up.
• Failure or another computer component.

Solution:

• Confirm internal power connections
• Troubleshoot to discover other failed devices.

Power Supply Trouble Shooting: PC fails to boot at all, no lights or beeps, fans don't start

Symptom:
PC won't boot at all; no lights or beeps, fans don't start.

Probable cause:

• PC not plugged in.
• The "hard" power switch in the back is turned off.
• PS has failed.
• No electrical service.
• The power switch has failed.

Solution:

• Make sure PC is plugged in.
• Use Multimeter to test PS and cords
• Make sure the 110/220 V switch on the power supply is set properly.

Power Supply Trouble Shooting: Not enough connectors for devices

Symptom:
You don't have sufficient pwr connectors for all the devices you want to install.

Probable cause:

• PS is undersized for your needs.
• Or, less expensive PS sometimes come with just a few connectors

Solution:

• Replace the PS if it is undersized
• Use a Y adaoter to split the existing connectors if the PS is rated to handle your selection of devices.

Power Supply Trouble Shooting: PC intermittently stops working or reboots

Symptom:
PC intermittently stops working or rebooting.

Probable cause:
Elec service supply problems (brownouts, blackouts, over heating, mismatched RAM)

SolutionL
Add a UPS or have electrician check buildings wiring. Confirm that UPS, surge protectors or generators are working.

Power Supply Trouble Shooting: Computer fails to boot

Symptom: PC fails to boot when powered on, but boots after Ctrl+Alt+Del is pressed.

Probable Cause
Power_Good signal from PS; either the signal isn't present, or is at the wrong voltage, or is sent at the wrong time.

Solution:
Replace the PS with a better model.

Power Use and efficiency

The average Pentium PC with a CRT might use about 200 watts of power and cost about $15 dollars to operate each month. Printers, CD burners and other periphs can add up to even more significant costs.

Power supplies themselves are a major source of power loss. A typical PS is only 70% efficient (the other 30% is heat,etc.)

Energy Star program encourages mfgs to create efficient elecs, and consumers to buy it.

See the "DISPLAY PROPERTIES" Screen Saver property sheet for options for hibernation mode, etc.

Power Supplies: Conditioning and Management

AC electric is a "noisy" signal with many variations.

• Blackout (total loss)
  
• Brownout (a brief decrease in V level. SAG). Demand greater than supply can decrease the voltage available to some devices.
• Noise (disruption of the signal) - lightning, RFI, industrial equipment etc can introduce noises into the line.
  
• Spike (very brief increase in V) Lightning, also first return of power after a blackout.
• Surge (longer duration) Extra V is dissipated through the circuit after high-demand devices are turned off.
  

Power conditioning (assuring high quality AC signal)

• Surge protectors - no protection against noise, brownouts or blackouts
  
• Battery Backup/UPS- battery power converted by an inverter and supplied to the device. APC PowerChute software; Standby UPS; Continuous UPS; voltage regulators
• Generators - home generators generally produce a very noisy and inconsistent AC signal - not good for electronic devices. There are computer-grade generators.

Power Supplies: Form Factors

Form Factor of the PS describes the size and shape.

The FF must fit the case and fit in relation to the mobo.

PS FF names match those given to system cases.

Usual standard is ATX/NLX for 486-class and Pentium class PCs.

• Includes the +- 3.3 V output for AGP.
  
• First to include "soft power" switch that replaced the mechanical ones.
  
• Replaced the two-mobo power connectors with a single connector

SFX for Pentium Class: does not probifr -5 V output for older ISA expansion cards.
WTX for Pentium Class: ditto.

Motherboard power connectors

The mobo is connected to the PS with either one or two connectors.

• Older std is two connector system. They were NOT keyed, so you could connect the plugs wrong, or backward, and damage the mobo.
  
• Single Power Connector is the new std are keyed. You can't insert them incorrectly (unless you use a hammer). The above image shows a single power connector on a mobo (the white plastic keyed slots).
  

Drive Power Connectors: Molex, Berg, SATA

There are drive pwr connectors and Mobo power connectors in a PC.

Drive power conns are stdized in size, shape, placement and the voltage carried through their wires.

• Peripheral conns, (Molex typically conn HDDs and CD/DVDs to the PS (see left).
  
• Floppy conns (BERG, mini-Molex) conn are smaller
• Serial ATA (the new version of IDE) are the third kind. (See right).
  

These connectors are "keyed" - they can be inserted into drives in only one orientation. This ensures that you connect right power inputs to the correct point on the device.

The Power_Good signal

Also called Power Good, PowerGood, Power_OK or PWR_OK signal

• A +5 V voltage supplied over a specific wire in the connector that sends pwr from the PS to the mobo.
  
• If the signal is not sent, the mobo will not boot.
  
• If the system won't boot when you press the PWR button, but will finish when you press Ctrl+Alt+Del, this indicates a problem with the Power_Good signal.

1. May not be arriving at the Mobo when expected (right at the beginning of POST) or
2. May not be at the proper voltage.
   
3. Replacing the PS will fix this.
   

Power Supplies: Standard Outputs

Most PSs provide 3 levels of output voltage at various amp ratings:

• AGP vid card (not available from older AT PSs): +- 3.3 V, 14 A
• ISA bus (At Bus) adapter: -5 V, 0.3 A
• Mobo, CD/DVD, HDD, PCI adapters, P III and earlier: +5 V, 30 A
• "Soft" power switch (ready-to-start mode) : +5 V, 0.85 A
• Older network adapters and serial ports: -12 V, 1 A
• Cd/DVD drives, HDDs, P4 and Athlon cpus, Mobo.
  

Note that more devices draw +12 V power than any other range. Therefore, make sure your replacement PS has enough +12 V connectors.

Power Supplies : Specifications

A PC power supply is the internal component that converts 110 or 220 V wall voltage to the DC voltages used by the PCs other componenets. A PS typically has a fan to cool it and (in some cases) help cool other components, too. It provides some "conditioning functions" to smooth out DC supplies during very brief spikes and drops from the supply voltage.

You often need to adjust the PS to run on either 110 or 220, and there is normally a small switch on the back for this adjustment, next to the elec cord port. (Be sure to turn the PC off before you do this).

PSs are rated according to the watts of DC power they output to the rest of the components. Modern PSs usually offer 300 watts; older ones typically offered 200 or less.

Note that the PS rating doesn't indicate what it will draw from the outlet. They only draw what is needed to supply the internal comps. If your system needs less than the full output, the PS will only draw enough elec to meet those reqmts.
The total wattage drawn by the comps should be less than what the PS offers:

• Mobo: 30 W (excluding CPU and memory)
• Memory: 10 W per 128 MB
• CPU: 65 W (Pentium 4 and Athlon) or 50W (older)
• Hard Drive: 5-15 W
• CD-ROM: 10-20 W
• FDD: 5-10 W
• Adapter card: 5-30 W

Inside the Case I

Typical internal components:

• The motherboard (primary circuit board)
• The Hard Drive
• The Power Supply
• The Adapter cards
• Wires and connectors

Typically you open the side opposite the rows of connectors and ports. Slide latches or screws are typically what secure the side to the case.

Most cases also include a removable front cover, which you remove to install a new disk drive. Typically held in place with snap clips and alignment posts.

Static Electricity: How to zap a mobo

Typically one object is made of an insulating material or a conductive material insulated from the ground. Charge imbalance creates an electric fiel that causes objects to attract of repel.

With PCs. the most dangerous aspect is what happens when statically charged objects are brought near each other. A high voltage/low amperage current - a static discharge. They aren't dangerous to humans, but can be very hard on electronics.

• 1000 V - will damage a chip
• 3000 V - a human will feel it
• 8000 V - visible spark
• 35000 V - typical carpet spark

So most of the time you won't even see or feel the discharge that damages your equipment.

Preventing static buildup:

• Don't shuffle your feet
• Keep the room humid
• Keep yourself grounded; you and the components you service can remain grd so the charges don't build up.
  
• Wear cotton clothing instead of more sythetic materials.
  
• Remove carpeting from service rooms.
  
• Use air ionization system to build up a neutralizing charge in the air

Preventing static discharge:

• Unplug the PC and touch the metal case before touching components
• Use an anti-static mat or an anti-static wrist strap or static safe bags.
  

Static discharge is not normally a problem when the case is closed.

Multimeters: electrical measurements

Multimeters can measure multiple elec properties.
You can measure resistance, voltage, current, or continuity.

• Resistance:
  

1. turn off the device and disconnect it from its power source. (Leaving it connected could damage the meter). Also might need to disc from its circuite.
   
2. Set the MM to read resistance. Might need to set the scale also.
3. Touch the black and red probes to either side of the circuit and read the display.

• Voltage:

1. Set MM to read either AC or DC. Also the range if needed.
2. Touch the black probe to the ground and the red probe to where you want to measure.
3. If you have an analog meter and the needle tries to swing backwards, you have the red probe on the ground.
   
4. Device must be turned on and connected to its power source.
   

• Current

1. You must break the circuit and insert the MM into the break.
   
2. The current in the circuit will then flow through the meter (which is designed not to disrupt the flow noticeably).
   
3. Clamp ammeters are used to clamp around a wire to measure the current flow.
   

• Continuity

1. Fuses intact or wires whole?
   
2. Which pins on one end of a cable are connected to which pins on the other end?
   
3. Set MM to display resistance (ohms) and look for circuits with zero resistance.
   

Most of the time, you might need to measure voltage, resistance and continuity (hardly ever current).

• Check the output voltage of a power supply at various leads.
  
• Check to see if approp wall voltage is available.
  
• Measure resistance most often when determining is a cable is whole.
  

Safety Precautions with Electricity

• Don't touch exposed elec contacts
• Touch only insulated handles and parts of tools, probes, cords, etc.
• Leave covers on equip unless you need to access components
• Work one handed whenever possible. (Current is more likely to flow from finger to finger instead of through your chest).
• Never insert anything other than a power cord into a wall outlet.
• Keep hands clean and dry
• Don't work with electricity on wet floors or in wet surroundings.
  
• Remove jewelry when working with elec (metallic items can increase surface area that is in contact with an elec source.
  

Electrical safety

• Current, not voltage (ie the amps, not the voltage) is the actual danger. A dangerous level of current is possible even with a 9 V battery.
• 1-10-100 Rule: You can feel 1 mA. 10 mA can put muscles into involuntary spasm. 100 mA can interfere with your heart and kill you.
  
• V = i x r : voltage equals current times amps
• At a given voltage, current increases and resistance drops.
  
• The human body under ideal conditions (small area of dry skin) has a resistance of 500 K-ohms.
• Moisture on skin drops this nearer to 5 K ohms.
  
• Immersed bodypart in water could drop this to 100 ohms.
  
• See All ABOUT CIRCUITS for more info
  

Examining the characteristics of electricity

1. A Kilowatt power supply delivers more power than a 500 W supply. (1000 W > 500 W)
2. A PC tech would be concerned output the output power rating of a power supply based on the requirements of the components inside a PC
3. A PC tech will be mostly concerned with the wattage on the power supply and the proper voltage feeds to each of the components. Everything we plug into it will draw different wattage.
   
4. Purpose of a PC power supply is to

• Condition the power supply
• convert AC to DC current
• convert 110 V to 12 or 5 V
• supply current for the resistance/ohms of the components.
  

Electricity and Static Electricity

Conductor - material permitting the flow of elec.
Insulator - material inhibiting the flow

Voltage - the force of elec. caused by a difference in charge/elec potential at two locations.

• - also called potential or potential difference.
• - more elec will flow when there is a > potential than when there is a <.

So more energy can be drawn from a high-voltage system

• - Typical households operate at 110 V (actually a range from 90-135 V)
• - Computer components use either 5 or 12 V.

Current - A measure of the flow of elec past a given point.

• - measured in amps/amperes (a count of electrons passing per second)

• Circuit - For current to flow, there must be a circuit (path) from the source, through devices, and back to ground. Complete circuit is "closed."

• DC - Current flowing in a single direction at a constant voltage through a circuit.

• AC - Flows repeatedly back and forth thru circuit at a varying voltage lever.

• Hz - a full cycle of AC power: voltage change from zero voltate to maximum voltage, then min voltage and back to zero. AC power in the US is a 60 Hz.

Resistance: The force that opposes the flow of DC through a conductor

Impedance : The force that opposes the flow of AC power.

• When this is present, elec energy is converted to heat or work.

Ohms : The measure of resistance.

• 1 Ohm is the resistance of a system with 1 volt maintaining 1 amp

Power : WATTS obtained by x voltage times current. A measure of the energy delivered by the flow of electricity.

• Power supplies are rated by watts or elec power they supply.

• Elec energy is elec power delivered over time, ie kilowatt hours.