I would like to share some of the mainboard repair experiences that I have encountered, maybe each main has a different disease, but this is a disease I have encountered and have successfully fixed.
*Some basic diseases of the mainboard would like to share with you, if there is anything, please teach me.
Main Asrock 333 D667 triggering the hexa code does not jump, causing the CPU socket to open, re-steaming the CPU socket, the main runs normally.
The main Asus P5GC-MX is sometimes reset, right at the dos, or win … etc screen, causing the CPU socket to open, re-steaming the socket, the main runs normally.
Main MSI 945PL could not be powered on, shorted on 2 quartz pins to activate dc power but the main did not boot, reheated the male main chip to boot normally.
Main Foxcon G31 power on main running but not boot ktra see FET supply 1.2 V for chip north and APG burned. The cause is the error ic oscillation isl 6321 proceed to replace the pair of FETs and the main boot isl 6321 chip normally.
Main Giga G31M can’t be powered on, can’t trigger the main circuit, remove the main VRM power supply to power dc! measure ktra, then 1 FET 12V dead, proceed to replace another Fet with normal boot main.
Main Giga 8i865GME-775 power on the test card says CO code C1 D3 41 50 FF the screen doesn’t turn up, plug in VGA card, the code stops 50 screens now scan imger bios ….. re-upload bios main running boot normally.
Main Asus P5AD2-E power on the fan rotates 1 2 turns and then turns off, unplugs the 12V battery to activate the fan rotation ktra foot en = 1.2v pgood = 0.5v error ic oscillator ADP3180 – change another ic to normal boot.
Main Asrock P4i45GV test card says Ad, the northern chip filter capacitor is swollen, replace the main boot filter capacitor normally.
Main Prescott 533 lost CPU power, because Pgood = 0V proceeded to replace FET 3055 at the top of the ram slot, the main boot normally.
Main intel 915GLVG flashed power, lifted the main ADP3188 ic to power it, tried another ADP 3188 and plugged in a fake CPU with power, plugged in a real CPU and lost power. — cause ADP3188 error, replace another ADP 3188 with normal CPU main boot source.
Main intel 478 status is when the power is on, sometimes it doesn’t, when jumping the hexa code, the power is lost. The cause is open cpu socket because the main intel wants to activate the dc source, then the CPU must be plugged in after steaming the main boot socket normally.
Main Giga 945GZM-S2 bios code 45 proceed to upgrade bios main boot normally.
Main Foxcom 45CMX lost CPU power due to loss of power Ram 1.8V replace ic oscilloscope ram IC 7120 (equivalent to RT 8150) ram has 1.8v source -. have normal boot CPU main source.
Main intel 845gvrs powered fan wobbled 12v pin pin, fan rotates normally -. main short vcore -. short the fet, remove the short fet and replace it with a new one, the condition is still the same! try instead of phase invert ic and main fet pair with normal boot vcore !
Main giga 945gcm-s2 lost reset and clock pulses. Measure north chip source = 0.6v. at pin D of fet Q287 = 0.6v powering fet Q287 is fet Q289 measured at pin D = 1.8 G = 10.3v foot S = 0.6v open condition fet enough -. fet does not know. Replace fet Q289 chip source north = 1.2v main boot normally
Main asus P5GZ-MX cardtest reported code 85, usb shutdow error screen after 15s. After 15s, the main self shutdow, ktra saw the loss of 5v power supply to the usb port. The diode capacitor is broken, proceed to replace the capacitor. main boot normally.
Main intel power on cardtest reported bios code E8 E9 EA EB, bios error. Updating bios main boot bt
Main giga 945gzm-s2 lost vcore, chip north, ram … proceed to replace OSC 6520 ( ic to manage ram ) main boot normally
Main 865G7 cardtest stopped the AF25 code instead of the north chip, still the same! North south enough cpu ram source ! source ram measured = 2.56v . change the main boot ram source fet normally
Main p4i65GV lost the reset pulse, check that the ram source fet is hot, lose the north chip source, the D and G pins of the fet have a source -. change to another pair of feet. There is a source of chip north of main boot bt, fet ram is not hot
Main foxcom 45GMX power on test card says FF not out vga on, out vga leave ! ktra found that the diode D20 (near the 12V vcore battery) was touched, proceed to replace the diode. Main boot out vga on .
Main Giga 945GCM-S2 full power, lost reset pulse. Conducted steaming the male chip had a reset pulse but the main did not boot. Replace with another male chip. Main boot bt
Main biostart 945GC-M7 TE lost reset pulse (with cpu source) ic error Lan remove ic Lan to main boot bt
Main asus p5kpl-am lost reset pulse, measured impedance of chip north 12 ohms, chip on other main 24 ohms, proceed to replace chip north main boot bt
Main dell 865 synchronously plugs in the cardtest code to jump normally, the caplock keyboard does not go out to the external screen, ktra found that pin 13 of the vga port has no power, measured impedance 47 ohms, found that this pin eats directly into the north chip, proceed to replace the chip with another main, the external monitor is out.
Main Intel D845GVFN
Phenomenon: When the power is turned on, there is a Reset signal, but the code C0 shows up and then stops, there is a short beep like a RAM error, when the RAM is put in the beep, but the hexadecimal number on the test card does not jump, it is still used at C0.
Cause and Alternative: Analysis:
There is a beep sound indicating that the CPU is working and the BIOS has been loaded. but the Hecxa number does not jump means the machine does not execute BIOS to test the devices, => BIOS error.
Download BIOS online but no, only Update.
Use another Main of the same type, Read out to get the BIOS and then load the Main with the above error => Main worked OK.
Mainboard – Main Preescos 533 Socket 478
Phenomenon: When the power is turned on, the power light on the test card flashes at a rate of about 1 second / time, when the power indicator flashes, there is a voltage drop, no reset
Cause and replacement: Caused by dead IC – SIO (Winbond W83627F), replacing this IC Main ran OK.
Mainboard – Main Foxconn 865M01 Socket 478
Phenomenon: When the power is activated, the power light on the test card blinks, remove the 4-pin power plug from the Main, then the power can be activated.
Cause and replacement: The above phenomenon is caused by a VRM short circuit, a short Mosfet lamp and a dead phase invert IC, the repair process is as follows:
Measure and check the Mosfet lights on the VRM circuit and see that the top 3 Mosfet lights are short (in fact, 1 lamp is short, but due to the parallel circuit, it should see 3 short lights), remove the 3 Mosfet lights above to check and see the second light. 2, when the lamp is short, the phase invert IC usually dies, but the phase inverting IC cannot be measured by the impedance scale, so I am as follows:
Leave the state of removing the 3 Mosfet lights above to leave the legs empty.
Power and power the source to run, measure the voltage at the 3 G pins of the 3 Mosfet lights on (leaving the legs empty), if their voltages are equal and about 8V are 3 good phase inversion ICs, if they are different then yes 1 IC died, when measured, the first and third lights on the G foot have 8V and the second light on the G foot loses voltage => dead conclusion IC 2nd phase reversal
Replace the phase invert IC and measure the voltage out, then replace the good Mosfet (taken from the equivalent position of the other Main) => Main ran OK.
Mainboard – Mainboard MSI N1996
Phenomenon: Main flickers when running, sometimes not, when not running, it loses Reset
Cause and replacement: Cause: broken CPU Socket pins
Check:
When the Main is not running and reset is lost, check the loss of VCORE power supply to the CPU, because the Main is short when running when it is not up to determine that this is a flickering contact phenomenon, possibly the oscillating IC pin or the Socket pin detaching.
Re-solder IC oscilloscope but not, solder Socket and Main worked OK.
Mainboard – Main Gigaby SK 478
Symptom: Test with Card Test Main has Reset but does not jump Hecxa
Causes and replacements: The above phenomenon is caused by the following reasons
Chipset north does not work due to broken legs, broken..
CPU not working due to Socket pin or wrong CPU BUS or CPU error
BIOS error or ROM error, ROM pin does not contact
When testing, press firmly on the back of the North Chipset and activate the power, the Main runs => Conclusion Main has a broken CS leg in the north
Solder the North Chipset and Main is running OK.
Mainboard – Gigaby SK775 – G31
Symptom: There is Reset but it does not run, does not transcode Hecxa
Cause and replacement: Re-soldering the CPU socket is OK
Repair process:
The above phenomenon is due to the following reasons:
> North chipset not running
> CPU wrong bus or broken
> Socket Socket
> ROM error or BIOS error
Replaced another CPU, loaded BIOS not running, when soldering Socket CPU Main was running.
Mainboard – ASUS P5GC-MX Main
Phenomenon: The main boot still has Reset, the Hecxa number jumps to the D4 code, then stops, receiving RAM.
Cause and replacement: – Solder the North Chipset and it’s OK.
Checking process:
Initially, when checking, the Hecxa number jumped for a while and stopped at D4 without showing up, so the following reasons were determined:
* BIOS error
* RAM error
* The Chipset pin is missing, so when starting the BIOS, the Video Card cannot be tested.
* CPU error
Try replacing the good RAM with the correct BUS but it doesn’t work, replacing the good CPU still doesn’t work, reloaded the BIOS but still the same. finally soldered the North Chipset, the Main was running OK.
Mainboard – Main FOXCONN Socket 775
Phenomenon: When the power is activated, there is a Reset signal on the Test Card, but the Hecxa number does not jump, so the Main does not start, no error.
Cause and replacement: – Main has reset signal means the voltage stabilizer circuit on Main has been active, Clock circuit has been active and Chipset male has also worked. The phenomenon of Hecxa numbers not jumping is because the North Chipset has not worked, the CPU has not worked or the BIOS cannot be loaded. After checking the socket of the CPU, it was still normal, replaced the CPU well and the correct BUS was still the same, I soldered the North Chipset again, after soldering the North Chipset, Main ran OK. The temperature when soldering this Main North Chipset is about 260 degrees Celsius according to the clock on a Chinese Chipset welder.
Mainboard – Main Pentium 3
Phenomenon: If you don’t plug in the keyboard, the device will start up, if it shows up for about 30 seconds, then stop, if you plug the keyboard in, it won’t start, won’t show up.
Cause and Alternative: The above phenomenon has 2 diseases:
Sick when plugging the keyboard into the Main does not start (good keyboard)
And Main runs for about 30 seconds, then Stop.
* With the first problem, when plugging in the keyboard, the Main can’t start, the reason is because the noise filter capacitors are detected right behind the PS/2 port, I removed these capacitors and the Main plugged in the table. enter key run OK
* The disease keeps running after being shown for about 30 seconds and stops, the reason is that the CPU is overheated, because the thermal paste on the back of the CPU is dry, creating a layer of insulation, I cleaned the CPU back and the aluminum piece radiate heat then apply thermal paste and Main is running OK.
Device: Mainboard – Main MSI socket 478
Phenomenon: When the power is activated, there is a Reset signal, but the Hecxa number does not run, does not display, does not report RAM errors.
Cause and replacement: The number of Hecxa does not jump is a sign of the CPU not working, but checked the CPU socket well, soldered the BIOS pin but it did not work, soldered the North Chipset pin also failed, but when taking it, soldering machine to re-solder the 8-pin oscilloscope IC of the 1.2V source voltage stabilizer circuit (power supply for Chipset), then see Main running, but turn it off for a while and turn it back on, if soldering the IC on the Main again runs yes, but replace the new IC in the same phenomenon. ???
Finally removed two ceramic capacitors with toothpicks standing near the 8-pin IC that Main was running normally:
KL: Main is detected by the noise filter capacitor standing near the 8-pin voltage regulator IC that has produced the above phenomenon.
Mainboard – Main Intel Socket 478
Symptom: Main failed to power on.
Causes and replacements: Main can’t hit the source due to the following reasons:
Broken Quartz 32.768KHz
Wrong position Jumper Clear CMOS
Broken or broken IC – SIO . pin
Broken or broken male Chipset legs
After the above analysis, I checked in turn and found that the bridge was lost in the Jumper Clear CMOS, took a bridge and plugged it into the Normal position => so I was able to activate the source right away.
After the power is activated, the CPU checks to see that Reset is good and there is a Hecxa jump but there is no RAM error (even though no RAM is attached) the Hecxa lamp says it is used at D4, after installing the RAM is still the same, the D4 error is not Not RAM but not Video Card error, this could be a BIOS error, then I removed the BIOS ROM and cleaned the legs for good contact, so the Main was running OK
Conclusion: Main did not contact ROM pins, customers self-corrected but added a disease that caused Jumper to be lost, leading to power failure.
PAN loses V-CORE “FOXCONN G31MV”
(other sources are enough from A–>Z) Only lost Vcore source. I also refer to nearly 20 topics PAN disease of this MAIN line… most of them found dead Q18-Q20 near SK fan==> steps to check Check: Replaced Q18 and Q20 (checked Q18 with 1v2 ==>OK, Q20=0.8v)
IC oscilloscope 8841: Pin 19=5v, pin 26=12v, pin 32(Vtt)=1v2, Pin PWGOOD 31 loss of voltage 3v3
##PAN 1: Biostar 945GC-M7 TE has enough power, clock, and reset.
Mainboard Biostar 945GC-M7 TE full power, clock, reset reset.All sources OK. Clock is good (Clock light on Test Card and CLCK measurement on fake load CPU), Reset light does not interrupt.
It took a lot of time, because subjectively thinking that having a Clock, there must be a PGOOD about the Nam chip. After beating everything, I just happened to notice this Main removed the CPU (there will be no Vcore) but the Clock light on the test Card is still on > this guy Clockgen circuit does not depend on PGOOD.
Check the circuit around IC L6703 Vcore source oscillation, SS_END / PGOOD signal (pin 46) is reversed phase 2 times through 2 tiny lights Q83, Q82 (near the top on the RAM slot) and then back to the South chip (pin 46 L6703) > Q83 > Q82 > male chip).
Install the CPU, on the source to measure the voltage again, see that battery 46 L6703 has voltage (about 3V), this voltage is put through 1 back into the B pin Q83. The Q83 pin C voltage 0V > OK, the B pin Q82 voltage is also 0V > OK, but its C leg has no voltage (should have a high level), inferring the Q82 CE rust detector.
Remove Q82 and then click again >>> OK, the code jumps smoothly, listens to a dear beep (this beep is sure to be loved by everyone who fixes the main)!!!
(It seems that many generations of Biostar Clock still run without PGOOD, please check for me).
Mainboard – Main BIOSTAR 945GZ
Phenomenon: Main runs for about 1 minute, then Stop, for a moment when the power is activated, it runs for about 1 minute, then Stop.
Cause and replacement: Cause: Due to the error of the oscillator IC of the VRM circuit, replace the oscillator IC of the VRM circuit with the symbol ISL6322, the Main has run stably.
Explain:
When analyzing the disease, with the Main disease running, it means that the components on the Main have been running, but after running for about 1 minute, then Stop, this is a sign of a certain component on the Main being overheated, from the above statement. I have checked the temperature of the components on the Main such as: Chipset south, chipset north, IC-SIO, BIOS, Clock Gen, all are normal, when I check the Mosfet lights of the VRM circuit (there are 6 lights divided into 3). pair) saw that two lights of one pair (temporarily called pair number 1) were very hot (long touch will burn hands) the other two pairs were only slightly warm, I changed the position of pair number 1 (heated) to position number 1. The other pair position (just slightly warm) shows that the position of the No. 1 pair is still hot, ie not because of Mosfet, then measure and check the oscillating voltage (measured on S and G), then see the voltage of the lamp on the upper side of the pair. being hot has an oscillating voltage of about 6V AC while the voltage of the lamp is on the same side but not hot only 4V AC => Conclusion faulty oscilloscope IC gave a disproportionate oscillation, leading to a phenomenon of 1 pair of work The capacity is overloaded and overheated…, after replacing the main oscillator IC, it runs normally.
Main Gigabyte G41M-ES2L. Phenomenon: The machine turns off by itself, turns itself back on using the tweezers at the foot of the Pon foot (Does not count the win error, because hardware repair must exclude those cases first. Yes. Replace the small diodes, resistors, capacitors connected to the source jack -> no. Continue to replace the IO chip (can replace hxs with gxs ) -> no. Finally proceed to steam the male chip again, or replace it. the male chip must work ok.
The mainboard was struck by lightning along the modem line, touching the LAN IC was very hot -> The machine could not be powered, the power on pin did not have 5V. Proceed to remove the network IC, the machine boots normally. You should attach a separate network card to use, instead of other LAN ICs, it won’t come up because the set fires the resistors, capacitors, diodes… In addition, there are some cases where the set can still enter DOS but it crashes into windows.
Main Gigabyte GA-945PLM-S2, lost reset signal, lost CPU voltage and RAM, replaced the RAM oscillator IC near the male chip, it ran ok. There are some matching cases that also cause CPU pressure loss. Just replace the equivalent capacitor to run.
Computer mainboard repair
Those are the diseases I have corrected, please take a look at it. Not all diseases are fixed as above because each main has different diseases. And these mainboards are also old now, newcomers to the profession refer to fixing these diseases first to improve their skills.
