saleem Smps Notes 13

7/28/2019 saleem Smps Notes 13

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SMPS NOTES

A/C 220V/230V supply is given to the line filter section.A line filter coil is connected in this section which function to remove any noise that maycome with the input AC supply. The filtered AC supply is received from the line filter

section is given to the Bridge rectifier section converts the AC supply into High voltageDC supply. High voltage DC supply received from bridge rectifier section is given to thefilter section when removes any ripples from the rectifier DC supply and forms a smoothDC supply. Two filter capacitors are connected in the filter section which function tofilter the DC supply in this manner ,an unregulated high supply is received from theoutput of filter section.

In a common types of SMPS this unregulated high voltage dc supply isconverted into high frequency current pulses by switching transistor. When this highfrequency current pulses pass through the primary winding of a transformer. ACVolts get induced in the secondary winding .But instead of using this technical in a

computer SMPS an SM transformer is used. High frequency signal is given to its primarywinding to get the necessary supplies from its secondary winding. This high frequencysignal is generated by an oscillator section and this signal is amplified by driver section.amplified signal received from the driver section is given to the power output sectionthrough the driver transformer. The driver transformer functions as a coupling betweenthe power output and power driver section. Amplified signal received from the poweroutput section is given to the primary winding of the SM transformer through thesecondary winding of protector transformer. AC volts are induced in the secondarywinding of the SM transformer because of this high frequency pulses. The induced ACvolts are rectified and regulated to get the necessary supplies that are used for thedifferent section of the computer.

As the high frequency signal which reaches the primary winding of theSM transformer passes through the primary winding of the protector transformer, voltsget induced in its secondary winding also, whenever these some fault in the outputsupply such as a short circuit or if there is overloading of the power supply then the voltsinduced in the secondary winding of the protector transformer also register a change thesevolts induced in the secondary winding of the protector transformer are rectified andfiltered before these are given to the protector section. Protector section sense thevariation in these volts and cut off the output supplies whenever there is some fault in theoutput supply.

Power supplies are two types:1. AT power supply.2. ATX power supply.

1.AT power supply:
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1. Power good signal.2. +5v3. +12v4. -12v5. GND

6. GND7. GND8. GND9. -5V10. +5V11. +5V12. +5V.

2.ATX Power supply:

SECTIONS OF POWER SUPPLY

1. Rectifier and filter section2. Output switching section3. Oscillator driver and Error amplifier section4. Protector section5. Output supply voltage section6. Power good section.

WATTAGE REQUIREMENT OF DIFFERENT COMPUTERS

1. For P.C 65 Wattage2. For P.C/XT 120 WATTAGE3. For P.C/AT 286 150 WATTAGE4. For P.C/ super AT386 200 WATTAGE5. For P.C/486 250 WATTAGE6. For P.C/P1,P2,P3 300 WATTAGE7. For P4 450 WATTAGE.

TROUBLE SHOOTING

Note:1. If any components are open,output supply will be high.2. If any capacitors are short output supply will be low.3. If any main capacitors discharging for using 47 ohms 5 watt wire wound resistor.

1.NO POWER:1. check the power cable2. check the on/off switch3. check the bridge rectifier4. check the capacitors5. check the output switching transistor6. check the output rectifier and capacitors of SM transformer secondary side.

2.Low output supply coming from SMPS:


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1. check the main capacitor voltage 330v2. check the oscillator I.C and related components3. check the secondary side SM transformer filter capacitor,diodes.4. check the driver transistor

3.SMPS working but no output:

1. check the power good section2. if any components is defective. If defective replace it.3. check the protector transistor or IC4. check the output capacitors and diodes.

4.AC fuse blow off:1. check the bridge rectifier2. check the main filter capacitor3. check the switching transistor4. check the related components of bridge rectifier and switching transistor.

5.System automatically restarted:1. check the input capacitors and check the output capacitors

2. check the all capacitors which are surrounding of SMPS transformer.3. check the oscillator and the error amplifier I.C or related components.6.System late starting:

1. check the input capacitors and replace it.2. check the output capacitors.

CD ROM

The block diagram can be divided in two major areas.The control section and the driversection. The control section is dedicated to the peripheral interface it connects to the PCs driver controller.

The driver section electronics will manage all the CD-ROMS physical operations Aswell as EMF decoding and error corruction. Driver circuitary converts and analog outputfrom the layor diode. into an EMF signal, which is interm decoded into binary data andCIRC(cross interleaved read Solomon code) information.

A drive controller chip and servo processor chip are responsible fordirecting laser focus, tracking sled motor control, spindle motor control and loadingunloading motor control.

CD(compact disk):The compact disk first appear in the commercial market place in the year 1982

introduced by Sony & Philips.

Mechanical Assembly spare parts:


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1. Lenseit is using for Read/Write the data.2. Spindle motorit is using for spin the CD/DVD3. Beltit is using for locking the tray &CD/DVD locking4. Gear wheel set--- it is using for locking the tray &CD/DVD locking.5. Tray motorit is using for moving the tray from open to close,close to open

6. Slid motorit is using for lence slide the top to bottom,bottom to top.7. Data cablesit is using for data signals carring the MLC to lence or MLC to frontpanel.

CD Data transfer speed:1. The data transfer speed is 150kilo bytes/secEx: 2x =300kb/sec

4x =600kb/sec50x =7.5 mb/sec.

Note: AT 50X CD with 650 MB of data can ideally by read in 86.7 seconds.2.CD-ROM spindle motor speed is 200 and 500 rpm.

DVD Data transfer speed:1.DVD data transfer speed is 2.7MB/secEx: 12x = 16.2 mb/sec speed

16x =22.1 mb/sec speedNote: The drive also lists an interface rate of 33.3mb/sec by using ultra DMmodel 11 and 16.6mb/sec at multimode model-11.2.DVD access time is 120 micro seconds to 200 microseconds.Carraying for CDs:

1.Dont bend the disk2. Dont heat the disk3. Dont scratch the disk4. Dont use chemical on the disk

Trouble Shooting:1. check the belt2. check the gear wheel set and liver3. check the data cables MLC to lence,MLC to spindle4. check the spindle motor5. check the lence6. servo processor

Tray problem:a. check the beltb. check the gear wheel set and liverc. check the data cable from MLC to front paneld. check tray motore. check the servo processor I.C

Reading problem:


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1. check the data cable from MLC to lence.2. check the lence motor and gear wheel3. check the lence shaft4. check the disk motor5. check the lence and replace the lence

6. check the Buffer IC to lenceCD ROM/CD WRITER/DVD ROM/WRITER not working(deadcondition):

check the power connector

Dry solder the power connector

Check the voltages 5v,12v supply to MLC.Note: 5v using for buffer IC and 12v using for servo processor ICto disk motor,motor and front panel.

Check the servo processor IC.5.Drive not detected:

Check the IDE cable

Check the BIOS setup Check the interface to buffer IC.

saleem Smps Notes 13

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