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Motherboard Gigabyte GA-8n-sli-royal

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jopapadogr

jopapadogr

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Hi all

I have the mobo GA-8N-SLI-royal and i would like a help.
The problem: I connect the 24 power supply connector, the ATX 12V 4 pins connector, and the 12V/5V 4 pins connector.
I took off the CPU and all the RAM's, I/O cables etc.
The CPU FAN blower in connected.
Then i push the power button and the Q23 (MOSFET K3918) starts boiling the welding solder and after a couple of seconds the PSU shuts off imidiatelly.
I measure the resistance between the +12V line and ground and it's only 12 ohms.
I measure the resistance between the +VCC3 line and ground and it's only 15 ohms.
I measure the resistance between the +NVCORE line and ground and it's only 5 ohms.
I took off all the electrolytic capacitors to the above lines. No change in resistance values.
I take off the PCB protection board (in the orange slot), push the power button and then it's open the FAN fully but after about 5-7 sec his speed is going down and keeps runing that way.
Any help would be appreciated

TIA

P.S. I have the circuit diagramm available
 

upload an image then i can explain how and what you have to check step by step.

- - - Updated - - -

also upload the schematic if you have
 

1.jpg2.jpg3.jpg
Here some photo's from my attempts
I upload the GA-8N-sli-royal mobo schematic.

Please help me to find out what to do
TIA
iamkamalrandhawa said:
upload an image then i can explain how and what you have to check step by step.

- - - Updated - - -

also upload the schematic if you have
Click to expand...
 

Attachments

  • GIGABYTE 8N-SLI Royal - REV 1.02.pdf
    1.3 MB · Views: 164

first remove the coil and then check resistance from the both pcb ends of coil respect to ground. If it shows the near to Zero ohm's then Check output Filter capacitors are shorted or not otherwise 100% nvidia chip is shorted, if input side is near to zero ohm's then mosfets are shorted. then remove the mosfets and check with your MM they are shorted or not?
jopapadogr said:
View attachment 77066View attachment 77067View attachment 77068
Here some photo's from my attempts
I upload the GA-8N-sli-royal mobo schematic.

Please help me to find out what to do
TIA
Click to expand...
 

I 've already remove all the coils and make some measurements.
Well from the left side where the FETs are located its normal value (high resistance) and to the rights side ex. NVCORE voltage signal is too low like i mentioned to a previous post (5 ohms, VCC = 13ohms etc)

When you say "filter capacitors" you mean ALL the small smd type capacitors or what? They are maybe 100's of them! Is there any easyest way to measure them or i must take off one by one and measure it?
TIA

P.S. off topic but i want to know if there is a good and cheap way to use a 2MP web camera like a digital microscope to check the pads and via's through my TV monitor?
 

100% north bridge is shorted. Filter capacitors are not small smd cap's. they are electrolitic or solid state cap's. Yess there are some microscopic cameras but i dont know where to buy it online. one of my freind was buy it from kolkata india for 6000 Rs.(120$).
jopapadogr said:
I 've already remove all the coils and make some measurements.
Well from the left side where the FETs are located its normal value (high resistance) and to the rights side ex. NVCORE voltage signal is too low like i mentioned to a previous post (5 ohms, VCC = 13ohms etc)

When you say "filter capacitors" you mean ALL the small smd type capacitors or what? They are maybe 100's of them! Is there any easyest way to measure them or i must take off one by one and measure it?
TIA

P.S. off topic but i want to know if there is a good and cheap way to use a 2MP web camera like a digital microscope to check the pads and via's through my TV monitor?
Click to expand...
 

Hi , can upload the GA-8N-sli-royal mobo schematic? please
I have some problem GA-8N-SLI REV 1.0 , and i don't know what append
Regrads
 

MOSFETs are safer in the circuit than out side, do not remove them, they are highly sensitive, when you buy them they come all three pins shorted for a reason. Try to connect a series low ohm high wattage resister to 5 and 12 volt line then turn it on and leave it on for a little bit. After a little-while touch the ics and other components to see if anything is very hot and that component may be the problem. Check to see which parts are supplied power by q23, you said q23 is boiling, that is a clue, something is wrong with that circuit.

Q23 boiling? That doesn't make any sense, that is a small transister 2n7002 and there is current limiting resister dr71 there is noway that can happen and that is in 5volts line too. So you have to be a little more specific.:cool:


jopapadogr said:
Hi all

I have the mobo GA-8N-SLI-royal and i would like a help.
The problem: I connect the 24 power supply connector, the ATX 12V 4 pins connector, and the 12V/5V 4 pins connector.
I took off the CPU and all the RAM's, I/O cables etc.
The CPU FAN blower in connected.
Then i push the power button and the Q23 (MOSFET K3918) starts boiling the welding solder and after a couple of seconds the PSU shuts off imidiatelly.
I measure the resistance between the +12V line and ground and it's only 12 ohms.
I measure the resistance between the +VCC3 line and ground and it's only 15 ohms.
I measure the resistance between the +NVCORE line and ground and it's only 5 ohms.
I took off all the electrolytic capacitors to the above lines. No change in resistance values.
I take off the PCB protection board (in the orange slot), push the power button and then it's open the FAN fully but after about 5-7 sec his speed is going down and keeps runing that way.
Any help would be appreciated

TIA

P.S. I have the circuit diagramm available
Click to expand...
 
Last edited:

Hi!
9864672200_1368521488.png
 
Last edited:

ohooo!! thanks is very nice , so do you have the complete schematic? this is very interesting too.
Regards thanks you
 

ovisocka said:
ohooo!! thanks is very nice , so do you have the complete schematic? this is very interesting too.
Regards thanks you
Click to expand...

Schematic is in post #3

P.S. Chinese font must be installed !
 
Last edited:

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