Notes
power delivery system in motherboards
Mar 29th
In this article we will discuss Power Delivery system in Motherboards . For more in depth training , join PCLR Course of chiptroniks or you can also buy our course materials with online support.
Power Delivery
Power delivery—Why & How
Why: Motherboard components need one or multiple stable and clean DC power to work correctly
How: (1) Power Supply directly to motherboard components (2) for the power which Power Supply can not provide directly, DC to DC power converter on the motherboard converts the power and provide to components
Voltages type needed
Postive DC Voltage: generally between 0V to 12V, generated by DC-DC converter 0.75V, 1.5V, 1.1V… or directly from power supply, like 3.3V, 5V, 12V
Negative DC Voltage: typically -12V
Motherboard voltage normally ranges from -12V to 12V
Tips: General speaking
Higher speed component=> lower voltage needed
(especially for IO function)
Current types needed
Simple answer: Power/voltage=current needed
Low power device: <2A, example: Clock chip, LAN…
Medium power device : between 2A to 50A: example: Fan, DIMM, Chipset
High power device: >50A, example: processor, high power DIMM, high end Graphic card etc
The low/medium/high is just general category, no standard
Tips: High current device has higher requirements on the PCB
Space, layers, cost, copper thickness…, all in all, bigger current,
more design challenge for power designer and CAD engineer
Examples: components Voltage & Current
Processor:
1.0V to 1.5V, 50A to 150A, 130W
DIMM:
1.8V/0.9V for DDR2, 1.5V/0.75V for DDR3, 20A to 40A, 50-100W
Chipset: 1.1V, 10-20A, 5W to 30W
Onboard device: 1.5A, 1-2A, 3.3V, 0.5W to 5W
PCI slot: PCI slot: 12V, 0.5A, 3.3V, 3A, 5V, 1A, 15W, 25W, 75W or more
Fan connector: Depends on fan used, ranges from 0.1A to 5A, 5W to 50W
Tips
Normally 1 Components need multiple voltage rails
depends on what function needed, such as ICH need
1.5V, 3.3V, 1.8V…, more function, more voltage rails needed
For example: ICH has more voltage rail than CPU
due to ICH has more functions
Voltage types by components function
Components may need several voltages by functions: below is general category
(CPU), VDD (DIMM), occupy most the power pin of the components
IO Voltage: Core Voltage: Main voltage for core logic, most of the power consumes on the main voltage) for the core function, example VCCP Voltage for BUS, example: CPU Vtt
Reference Voltage: voltage used for signal sampling
Analog voltage: Some components include analog function, so analog voltage needed, such as Video, PLL circuit, analog voltage require to be clean ! Need to be separated from normal voltage
Components may contain 1 or more type of voltages depends on
Function needed, such as ICH need all 3 above voltages
Voltage types by power state
Some voltage are only required for certain power state
Normal Voltage: Voltage existing when the system is at S0 to S2 state, which means system is at ON state, like CPU main power, fan power, which is main power for the system
Battery Voltage: Voltage existing when the system at AC OFF status, it is powered by onboard battery. Example RTC clock
Standby Voltage: voltage always exists at S0 to S5 state (DC OFF), which means system at DC off state, AC power code is plugged, it is used for board power on/off logic and wake up function and some management function and other functions need to be functional at main power off state, remember, when AC power cord inserted, standby voltage exists !!
Aux Voltage: Voltage switch by between Standby voltage and same Normal Voltage, the main reason of Aux voltage is the function is needed through S0 to S5 state, but standby power can not provide enough current at S0-S2 state due to the device consume more power at S0-S2 state then S3-S5 state, so voltage need switch from standby voltage to normal voltage to get enough current , example: DDR voltage 1.8V, when system is at S3, the Aux voltage comes from 1.8V standby power to keep DIMM refresh, after power on to S0 state, Aux voltage switch to 1.8V normal voltage to support DIMM normal read/write (which consume much more current)
Components may contain 1 or more type of voltages depends on
Function needed, such as ICH need all 4 above voltages
Let us take a look at a real sample-Chipset
G41 MCH (north bridge) function/power mapping
(not exactly correct, just for example)
Another example—ICH 10
ICH 10 has require more than 20 voltage rails !! due to lots of functions integrated in ICH 10
Refer to product EDS for pin definition and power requirement
Example 3—PCI-E slot Power requirement
This voltage supply to add in PCI-e card, Card is required to design within this limit
Overall Power Delivery Example–Thurley
Overall Power Delivery Example2—Romley
Motherboard Input Power
Now, we know what kind of power (voltage/Current) needed by components, but where does it come from? Answer: from Power Supply, directly or indirectly
Power Supply Output (motherboard input)
Power Supply output type:
Multiple Output:
Power supply has multiple DC output rail (NOT connector)
Popular 12V, 5V, 3.3V, -12V, 5VSB and other voltage
12V output may have separate rails, like 12V1, 12V2, etc for 240VA protection
Single output: 12V or other voltage only
Power supply has single DC output, 12V is most popular
Battery is single output example
Power Supply output interface:
Connector: board to board or board to cable connector
PCB gold finger: PCB to mating connector
Tips:
Most of single output PSU also has standby output, like 5VSB
Power Supply Output example 1
Desktop ATX PSU : Multiple output, cable + connector
Server EPS12V : Multiple output, cable + connector
Power Supply Output example 2
Notebook Adapter:
19V Single output, connector, connect to motherboard directly
Hotswap module :
12V single output, gold finger and board to board connector
Note:
normally it also has 5VSB output
Motherboard side interface
General Rule: mate with power supply output
Connector
Gold finger mating connector
Board to Board connector
Motherboard power rails & Power supply rails
As we talked before, multiple-output power supply has multiple output, each rail will have current limit, and each rail are separated below is example
Same for motherboard, motherboard will also have multiple rails, like 3.3V, 5V, 12V1, 12V3a…, each rail has current requirement, so we need to mapping the power supply rails to motherboard rails to make sure both power supply & motherboard rails can be met
Next page is example
Rail mapping Example
Power supply connector/rail mapping
Caution:
Power supply rail can be separate to support multiple
motherboard rail, but reverse is NOT allowed!, otherwise it will
Short power supply rails and cause protection
DC to DC converter
So far, we know how power supply provide voltage rail to motherboard, like 12V, 5V 3.3V, etc by connectors or PCB gold finger or other method, but for the other voltage power supply can not provide, like 1.1V, 1.5V, 0.8V, we need DC to DC converter on the motherboard to convert the power supply voltage to the voltage we needed
DC to DC converter also called Voltage regulator (VR)
DC to DC converter (VR) types
(1) Linear voltage regulator
-Low current
-Low efficiency
-Low cost
-Simple
-Clean (little noise)
-High current
-High efficiency
-High cost
-Complex
-High noise
Linear VR
-
Simple & Clean (little noise)
-Low current
-Low voltage drop
-Low efficiency
-Low cost
(1) Why low current and low voltage drop?
vdrop on the VR= Vout-Vin, so the power loss = I x Vdrop, for example: Vin=3.3V, Vout=1.5V, 2A, so the power loss on converter is (3.3-1.5)x2=3.6W, assume 50C/W, so the temp rise will be 150C, which is burn the components, so only low current and low voltage is allowed, Linear VR only support low current requirement
(2) Why low efficiency?
The efficiency= output power/input power, obvious, it is low efficiency due to the power loss on the converter is big, the bigger difference between Vin and Vout, the lower efficiency is.
(3) Why simple & clean & low cost
It is simple & due to just a few components needed
It is clean due to no switch components, it is easier to place & layout the linear VR
Switching VR Types—Single Phase
-High current
-High efficiency
-High cost
-Complex
-High noise
Basic working principal is by control the mosfet PWM value to adjust the output voltage, Vout/Vin=PWM%, for example: 12V to 1.5V, PWM=12.5%
Switching VR efficiency is between 80 to 98% depends on VR design, the main power loss is VR Mosfet switching & conduct loss
It can handle high current due to high efficiency
High cost /complex is obvious: it need chip, mosfet, inductor, capacitor…
High noise: due to switching method and mosfet switching, it has much higher noise than linear regulator
We will NOT discuss how VR works here, refer to VR training slides
if you are interested, Overall speaking, VR is a complex technology
Switching VR Types—Multi Phase
VR example
Switching VR—single phase 12V to DDR 1.5V
Switching VR—multi phase 12V to CPU Vcore
Linear VR–3.3V to IOH 1.8V
Linear VR–3.3V to IOH 1.8V
VR placement & layout
CPU VCCP VR placement
CPU VCCP VR copper planar
How to Reball
Mar 4th
In this article , we will show how to reball . The following video will describe the reballing process in great detail.
Tutorial on removing North Bridge with BGA Rework Station
Mar 3rd
In this article , we will cover how to remove North Bridge with BGA REWORK Station . Since the best BGA Rework Station currently available in the Market is Jovy-Systems RE-7500 . We will show its working in the post .
BGA Reballing guide
Mar 2nd
In this tutorial , we will discuss simple procedure for reballing process. Hope you will enjoy it . Look at our complete BGA REWORK SOLUTIONS
Bga reballing guide
View more presentations from Swastik Pandey
Career in Chip level Repairing
Feb 7th
In this article , We will explain the essence of chip level repairing together with the happening future of the chip level technicians . We will also explain How CHIPTRONIKS stands tall in this market .
Every year thousands of Desktop PCs, Servers, Printers, Laptops etc are being sold and these Electronics Products becomes faulty/defective during their warranty as well as after warranty. As it is well known that in the First World Countries, the MNC Companies have monopoly on their products and as such they have tried to dominate the Concept of USE and Throw, secondly the cost of manpower in repairing the faulty devices are so high that the Chip Level Repair Technology can not be justified. As a result these MNC companies who are the manufacturers of Computer Systems and its Peripherals have never favoured the development of the Components Level Repair so that they can sell a complete PCB Assembly of any peripherals at high price.
In developing countries like India , African nations , the scenario is pretty different owing to low manpower and economical status . These countries are obsessed with term longevity and mileage . So people would like to use the electronics components as long as possible . This develops a huge market fro repairing.
CHIPTRONIKS which is led by the Intelligent team of IITians , the leader in technology has been the frontrunner in delivering technical training developed a methodology for chip level training . Its a common notion and practice that the experienced guys in this market tried to avoid sharing of knowledge and tips they have gathered . But this attitude among the experienced technicians was a big roadblock to developments in repairing technology . CHIPTRONIKS dedicated research and development created the feasibility of such training In India and now students and technicians across the world are flocking to our labs for such training . Moreover the the component level repairing(chip level) can be done at 80 % of the cost , so the value of this type of repairing has increased.
There are so many institutes which provide repairing training at card level but none of them have the expertise and capability to offer chip level training . In a way the training offered by them are only 25 % . So CHIPTRONIKS attracts not only fresh technicians but also experienced engineers to gain the fruits of chip level repairing technology.
ADVANTAGE OF CHIP LEVEL ENGINEER OVER CARD LEVEL HARDWARE ENGINEER
The advantages of chip Level Engineer over Card Level Engineer will always be there because of better troubleshooting knowledge by understanding the measurements of parameters of ICs and discrete components of which each peripherals are made of.
For example, a DMP printer’s have logic card problem, which will cost about Rs. 3000/- for a new Logic Card in order to Service it, so a Card Level Engineer will suggest to the customers to buy a new printer’s logic card where as a Chip Level Engineer will suggest to repair the faulty logic card at approx. Rs. 500/- and bill at Rs. 1500/- to the customer. Therefore the demand for the Chip Level Repairing is there all over India.
REMUNERATION OF CHIP LEVEL REPAIR ENGINEER
A Chip Level Repair Engineer will get highest salary in any firm a compared to Card Level Hardware Engineer. So those who know the Chip Level Repair Technology are the prestigious and elite ones. Generally any Hardware Engineer who after learning Chip Level Repair Technology should get an increment of about 25%-30% on his salary.
CHIPTRONIKS Advantage
Our all trainers are Level 4 repairing engineers who can handle any type of repairing themselves plus they are aware of the ESD norms and so they can guide the precautionary steps needed for chip level repairing . CHIPTRONIKS posess advance equipments like : Jovy System BGA machines ,Xytronics Soldering station, JBC De-soldering stations , SMPS load tester ,Repower Cell test system,RAMCHECK PLUS MEMORY TESTER , OSCILLOSCOPE (IWATSU SS7840), Point Soldering manchine and many other speciL TOOLS .
CHIPTRONIKS has also developed manuals for all repairing the motherboards , monitors , laptops , smps . These all manuals are all practical based . Our manuals are even used by many companies .
So I think joining CHIPTRONIKS will fulfill your dream of becoming a chip level engineer .
Toner refilling process
Nov 13th
| Basic Steps in Refilling |
| In refilling each ink cartridges, there are some basic steps, that we have to follow. These are;
1. Cleaning Now, we are going to have a closer look to these steps. 1. Cleaning: This is the most important phase of a cartridge refilling. Cleaning starts with applying pressurized steam to print head and ends with taking the waste ink out of the cartridge. I. Steaming Print Head: In order to apply the pressurized steam, we have to use a steam generator machine. They have a water tank and produce the needed steam by heating the water. Since ink is a very sensitive substance, it is subject to drying when it interacts with air. Therefore, the main idea in steaming the print head is to soften dried ink at the edge of nozzles and ink channels. It is very important to remember that the steam gun should be pointed in a perpendicular position. Pointing in a diagonal or an inclined position could damage the print head and even remove the plate. Steam should be applied for approximately 10 seconds. II. Waste Evacuation: After we soften the dried ink at the print head, we can switch to removing the waste ink out of the cartridges. Please note that if the cartridge has not been refilled before, you can skip this step. The main concern in removing the waste ink is the final quality of printing. In other words, as we cannot make sure about the quality of the previous ink refilled to our cartridge, we take the waste ink out of the cartridge. 2. Refilling: After we clean the cartridges, we can continue with refilling. In general, there are 2 refilling techniques; normal and vacuum filling. Normal filling is used to fill canister type cartridges. Some of the canister type cartridges has air pockets such as HP 6615 or 51645. In normal filling, the air inside in the cartridge is removed by vacuuming from the print head and filled with ink by using refill clips from the print head again. As these cartridges have no sponges, there is no need an isolated environment for refilling such as vacuum chamber. On the other hand, vacuum filling is used to refill sponged cartridges. Due to the physical rules, when the cartridge runs out of ink, the tissues of the sponge is filled with air. And, this air should be removed prior to refilling. Otherwise, due to the existence of air inside the sponge, we cannot fill the original volume of ink such as 10 ml to the cartridge. Furthermore, remaining air blocks the path, that the ink is pulled down through nozzles. And this causes the cartridge stop printing after several print outs although there is still some ink inside. Remaining air also makes pressure on the ink and pushes it down, which leads to ink dripping. In order to overcome these problems and to refill original ink volume, we use vacuum chambers. In a vacuum chamber, first the air is removed and chamber is isolated. Afterwards, as there is left no air particles or bubbles, we can fill the ink to sponge thoroughly. 3. Testing: As we refilled our cartridge, it is time to test its printing performance before we give it back to our customer. The best testing material for cartridges is the tissues. We touch the print head to the tissue quickly one after another. If we see some missing lines in the tissue, it means that, some of the nozzles need some more vacuum in order to take the air or resolve the clogging problem. And afterwards, in order to test a cartridge thoroughly, we use and recommend you to have some printers in your store. Because, with a printer, you can test both the printing of a cartridge and its electronic circuits. Furthermore, some printers can test more than 2 cartridges. As an example, we indicate the following printer models and the cartridges, which can be tested with them. * HP Photosmart 7400 Series: 8727, 8728, 6656, 6657, 6658 So, 11 cartridges with only 2 printers! As we test the refilled cartridge in a printer, we can observe its performance from the print out page. If we have some missing lines in the print out page, but not in the tissue, then it means that some parts in the electronic circuit became faulty and therefore, the printer does not use the nozzles associated with these parts. 4. Sealing the Print Head and Packing: If test results are satisfactory and we have observed that the cartridge performs well, then the next step is to seal the print head in order to protect it from drying and pack it. In sealing the print head, we put a drop of cleaning solution to the print head and wipe it with a dry and clean tissue. Afterwards, we put some blue tape over the print head and wipe our finger around the print head. If you touch the print head in sealing, then this will make a small air pressure between the blue tape and print head and lead the ink come out. And, if it is a color cartridge, the colors will be contaminated. After sealing carefully, we can put our cartridge into a CD bag and close it. If you have a vacuum and seal machine used in kitchens to store the food fresh for a long time, it would be a better idea to vacuum the air inside the bag and seal it. |
Mobile Software Repairing
Nov 2nd
When some fault develop with the mobile phone handset, one can repair it using the following methods
- Hardware Repairing
- Software Repairing
Hardware/Software Repairing
In hardware repairing, various components of the handset is checked for faults. One should first check the battery for proper supply and contact, replace with a known fully charged battery and check the handset.
Next, various points on the circuit board should be checked for proper voltage/signal.
If one finds some problem with the components, then it is called hardware fault.
If the fault could not be diagnosed at the components level then the-fault could be with the software inside the handset.
Program to help the mobile phone carry out its different function are stored inside the mobile phone’s flash memory. This program is commonly known as “mobile software”.
This software could become corrupt due to various reasons and could generate different faults. Some of the faults due to problems with the software are
- Dead mobile phone
- Hanging of mobile phone
- Phone automatically restarts
- Automatic Security Lock
- Network related problems
- Mobile shows wrong functions
- Lose of content etc
Many a times the non-operation of the handset could be due to some fault in the hardware and the software both. If this is the case then one needs to first rectify the hardware fault before trying to clear the software fault.
Various Lock of Mobile Phone
One can also use the software to remove various lock of the mobile handset. Following are some of the locks which can be removed using the software.
- Keypad Lock
- Phone Lock
- Security Lock
- SIM Lock
Keypad Lock
As the name suggests this lock, locks the handset’s keypad, one will not be able to use the keypad for any type of number or text entry.
Even when the keypad lock is active one can answer incoming call by pressing the keypad keys.
Different handsets use different method to enter into keypad lock mode and to remove the lock. When the phone is in keypad lock mode, pressing of any key on the keypad will display a message on the screen, explaining the process to unlock the keypad.
Phone Lock
In this mode the handset cannot be used to make/receive any call, even though the keypad stays active during this lock.
In this mode, when the handset is switched on, it asks for an unlocking code known as PiN or “Personal Identity Number”.
If this PIN is entered correctly then only one can use the handset. This prevents an unauthorized person from using the phone.
Security Lock
Security lock is used to lock all the functions of the mobile handset. When the security lock is on, the phone asks for the PIN code when it is switched on.
Some handsets may ask for the PIN number even when the SIM card of the phone is changed.
This facility is not provided on all handsets.
SIM Lock
When one buys a mobile handset from mobile service provider under some scheme, the provider may lock the handset with the SIM card in the phone.
This prevents the user from using the handset with SIM card from some other service provider.
Note: If wrong PIN code is entered more then a set time in a row, the phone becomes permanently locked and you need to take it to a service center to unlock it.
Most of the handsets use 0000, 1111, 1234, 8888, 9999, 12345 etc as their default security code, which can be changed by entering into proper menu option.
For more detailed training , join our mobile repairing course
chip level(sample)
Oct 27th
Motherboard Components are two types
Hole Through Components: Processor Socket (PIII), RAM bank, Expansion slots, I/O Ports, etc
SMD (Surface Mounting Device) Chipset, IC regulator, Mosfets, Tantalum Capacitor, Resistors Processor Socket in the case of PIV etc
Motherboard PCB
Motherboard PCB can be made up of Fiberglass or Bakelite. PCB can be available in multiple layers. The layers structure enables multiple wires to send data without their signal interfering with each other. The multiple layers also add strength to the Motherboard.
Layers of PCB
Single /Double layers
Four Layers
Six Layers
Eight Layers
Ten Layers
Twelve layers etc
Note that PIII Motherboard available in Four layers & PIV Motherboard available in six layers
Top & Bottom Layers of PCB pass data signal, Clock signal, Reset signals etc
Inner layers of PCB pass Current
Tools used in Motherboard Repairing
Soldering & Disordering Tools
Cleaning Tools
Basic Tools for e.g. Tweezers, Paper Cutter, Scissor etc
Testing tools Debug Card, DMM etc
Hot air Gun/Disoldering Pump
Liquid Flux etc
Motherboard Repairable Condition
- Repairable Condition
- Non Repairable Condition: Service Engineer is not full skill
Due to Non availability of Components or burned or damaged PCB
Represents & Testing of M/B Power section Components
- R - Resistor
- D - Diode
- Q - Mosfet
- C - Capacitor
- L - Inductor
- Q or Tr - Transistor/MOSFET
- F - Fuse
- RN Resistor Network
- CN Capacitor Network
- U IC/Chipset
Resistor: – It is used to oppose the current.
It is checked on Ohmmeter.
It has two legs.
Diode: – It is used to convert the AC to DC.
It is checked on range of Diode.
It has two legs i.e. +ve & -ve. (Dark area shows the negtive)
Mosfet: – It is used to regulate the voltage.
It is checked on range of Diode.
Mosfet show one legs show the value and other show the multimeter value i.e. infinite value
It has three legs i.e. Source, Gate, Drain.
Capacitor: – It is used to store the electricity & purify the impure DC to pure DC.
It is checked on range of mf and also checked on Mega ohm i.e. If capacitor is ok than it show the resistance
It has two legs i.e. +ve & -ve.
Inductor: – It is used to filtration.
It is checked on range of continuity.
It has two legs.
Transistor: – It is used to amplifying the signal.
It is checked on range of Diode.
It has three legs i.e.Emmitor, Base, Collector.
Motherboard Testing
Through Debug Card: It is testing device which can attach on PCI slots and it generates the Hexadecimal Codes from where the system engineer sense the faults in Motherboard.
One thing is noted that the hexadecimal codes are differing according to the BIOS.
Some Common codes are following
Motherboard Testing (Debug Card)
Code OK Memory Error mp Error
00 C0 BC
FF C1 EA
7F C2
2F C3
26 D0
27 D1+continue long Beep
28etc D2
D3
60+continue long Beep
Through BIOS beep Code
BIOS show some beep code in POST screen from where the System Engineer senses the faults in Motherboard. BIOS beep codes are also vary according to the manufacturing of BIOS. Some common BIOS beep codes are following:
BIOS Beep Code
Number of Beeps Solving Problem
1 short Beep System is OK (Acceptance Beep)
2/3/4 short Beep Check the RAM & Video adapter
Card properly connected.
5 short Beep Check the RAM properly installed or not check the mP. Replace the mP & M/B.
6 short Beep Try attaching a difference K/B.
7 short Beep Replace the CPU / M/B
8 short Beep Check the Video Card (Display) 9 short Beep Check the BIOS Chip is properly
Attached or not
10 short Beep CMOS Chip Problems
11 short Beep Cache memory Chip
1Long 3 Short Beep RAM Problem
1Long 8 Short Beep Video Card Problem
Continue long Beep RAM Problem
Precaution while rework on Motherboard
- The value of each component should be same.
- The size of capacitor should be same or less.
- The capacitance of capacitor should be same.
- The resistance of resistor should be same.
- Hot Air Gun should be handled properly
- Working surface should be neat & clean.
Rework on M/B
- Chips, IC
- M/B Power Section i.e. capacitor, mosfets, inductor
- Rework on I/O ports.
- Rebuilding the burned or cuts tracks.
To give Motherboard faults
-
- System/ Motherboard is giving the display but restart again &again after completing the POST Sol: 1 first of all visualizes the M/B carefully. There can be some burnt or damage tracks or components
2 check the electrolytic capacitor it can be damage
3 checks the crystal oscillator mounting near the clock generation chip replace it
4 The clock generation chip may be bad
5 Bad BIOS
6 Press the north bridge and the south bridge chipset with a grate force with the help of your thump.
7 Reinsert the BIOS.
- M/B is dead no display on monitor and the DEBUG card is giving 00; FF; 88 codes but it is switching on properly.
Sol: 1 First of all checks the physical condition of M/B i.e. burnt or worm out tracks on the M/B.
2 BIOS may be bad or incorrectly flashed
3 check the electrolytic capacitor if found bad replace it, while replacing the electrolytic capacitor you should take care for:
1. The volume or WVC work voltage and capacitance should be same
2. Capacitor size should be same
3. Polarity should be correct otherwise it will blast after some time.
4 bad BIOS replace the BIOS with the same
5 super I/O chip may be bad replace it.
6 check the voltage regulator i.e. MOSFETS replace if found bad
7 If problem is still than check the mp or RAM using
replacing method
8 If problem is still than problem in m/b
- M/B is dead no display on monitor & the DEBUG card is giving C0; C1; C2; C3; D0; D1; D2; D3etc.
It is switching on properly also the internal speaker is giving the continuous long beep.
Sol: check some burn or worn out track near the RAM slots and Mp sockets
2: check the operating voltage i.e. 3.3 V for SDRAM and 2.5V for DDRSDRAM into the RAM slot.
If this voltage is absent then check the voltage regulator [MOSFETS]
3 clean the RAM slot with acetone .it may be dirty or corrosive camp
4 If all these are ok than replace the RAM
- M/B is dead and is not switching on.
Sol: 1 check the physical condition of M/B
2 Check the CMOS clear jumper it may be set on clear, set it on normal mode.
3 Check the dry soldering on Motherboard Power Connector
4 the super I/O chip may be bade. Replace it.
5 south bridge chips may be bad.
6 some times the M/B inner layers may be damage so in this condition the M/B cannot repair further.
7. Before performing all above actions check the SMPS
- The M/B is switching ON/OFF properly & is giving the display but it hang\halt after completing the POST or after 10-15 minutes.
Sol: 1 check the physical condition of M/B
2 check the M/B’s power connector .it may be dry solder or spark.
3 check the electrolyte capacitor
4 also check the voltage regulator i.e. MOSFETS
5 some time the BIOS may be or incorrectly flashed so refresh or replace it
- M/B is giving the display but the K/B is not working and during POST the following message is display.
“Key board error”
Or
“No key board present”
Solution: 1 the K/B connector may be dry solder
2 Some time there is some burnt track or
component near the K/B connector
3 if still problem proceed than bad super I/O chip
4 Before performing all these actions first of all check keyboard itself
- The M/B is giving the display but parallel port is not working
Sol: 1 check the resistor network mountings near the
parallel port
- check the track from parallel port to super I/O chip
- Dry soldered or bad parallel port
- Some time the super I/O chip may bad
- The M/B giving the displays but one of the serial port is not working
Sol: 1 serial port may be dry solder
2 check the track from serial port to GD75232 chip and from GD75232 to Super I/O chip
3 GD 75232 chip may be bad
4 Some time super I/O chip may be bad
- M/B is giving the display but FDD connector is not working
Sol: 1Check Dry solders on FDD connector
2 bad floppy drive connector
3 visualize the physical condition of connector and tracks between the FDD Connector and super I/O chip
4 the super I/O chip may be bad
-
- The M/B is giving the display but not audio out put
Sol: 1 check the audio controller is not disable trey & jumpers on M/B some times. The audio controller is disabling through BIOS so first of all check these setting.
2 If these are ok then check the crystal oscillators and voltage regulator IC LM 78xx; LM 317; LM34 mounted near the audio controller chip
3 Bad BIOS so either replace it or refresh it
4 The audio controller may also be bad.
SMPS Voltages
Voltage used by M/B components
SDRAM: 3.3 V
DDRRAM 2.5 V
DDR2RAM 1.8 V
DDR3RAM 1.5 V
P3 1.45v to 1.95 V
Cel3 1.6V to 2.1V
Cyrix C3 2.0V
PIV & Cel4 1.45V
