What is SMPS
SMPS or switched mode power supply
is an electronics device that is used to convert AC to DC, AC to AC, DC to DC
and DC to AC voltages. The circuit consists of transformer, rectifier, voltage
regulator and a filter. The input supply is turned on and off by MOSFETs (Metal-Oxide
Semiconductor Field-Effect Transistor) and outputs a high efficiency, regulated
voltage. The SMPS used in computers is of AC to DC type supply.
Output Voltage of SMPS
-12V (Blue) – Required by some of
the serial ports. It is required by very few serial ports and is provided to
maintain compatibility hardware.
-5V (White) – Required by some older
floppy controllers and ISA (Industry Standard Architecture) bus cards.
0V (Black) – Required to complete a
circuit with other voltages. It is ground voltage also known as earth.
+3.3V (Orange) – Required by the
processor, DIMMs, PCI/AGP cards. This voltage was introduced in the ATX form
factor and is available in the ATX/NLX (Advanced Technology Extended/New Low
profile Extended), SFX (Small Form Factor) and WTX (Workstation Technology
Extended) form factors
+5V (Red) – Required by the disk
drive logic, voltage regulators, ISA cards, SIMMS and other miscellaneous
components of the system.
+12V (Yellow) – Used by motors in
the system, from drive motors to cooling fans. It is also distributed to the
system bus slots for usage by cards which may need it.
Power Supply Control
Signals
PG Signal (Gray) – Indicates to
motherboard that all the supplies (+12V, +5V, -12V, -5V, +3.3V) given are at
proper level and also informs to the computer that power supply is working
properly and prevents computer from operating on improper voltage levels.
PS_ON (Green) – Controls the power supply and is a
part of ATX standard. Power-on carries a low- voltage logic-level signal from
the motherboard to the power supply that indicates when to turn on and off.
Different Connectors of
SMPS
ATX 24 Pin output voltage connector – This connector is used to provide power supply to the
motherboard. It is also called as PC main power connector.
Standard Peripheral Power connector (Molex) – It use 4 wire connectors which are commonly called Molex connectors. The hard disk drive, CD/DVD drives use Molex connector.
SATA power connectors – It is a 15-pin connector. The large numbers of pins are used to supply three different voltages – 3.3V, 5V and 12V.
PCI-E 6 Pin connectors – It is used to provide extra 12V power to PCI express expansion cards.
Troubleshooting of SMPS
Problem – PC is
not starting
Check the AC line.
Check power cable by using
MultiMeter.
Open the system case & remove
all the connectors from drives and motherboard.
Short pin No. 14 & 15 or GREEN
and BLACK.
Problem – Power
Supply Fan does not work or emits a lot of sound.
Shutdown the system, remove the
system case cover and clean the dirt or dust from the fan and power supply unit
with a vacuum cleaner or with compressed air.
Check the power supply fan and
replace it if it has any defect.
Problem – System
shutdown after some time due to a power supply problem.
Check whether the SMPS fan is
properly working.
If the system restarts
automatically, make sure that the wattage capacity of the SMPS matches the
computer requirement.
If the computer takes more time to
boot, check wattage rating of the SMPS.
0 comments:
Post a Comment