ASROCK 775i65G Rev2.03 / Turns ON / No Display

[DsB_79]

hi, i have a asrock 775i65G Rev 2.0 that starts but does not display any image.

I put a debug card on pci slot and the following hex code appears 13 20.

Steps that i have tried:

Reflash bios , i went to the support site of the board and download the dos version to do the reflash, but this does not solve the problem,

I put external video card on slot agp but the error code is the same so this does not resolve the problem,

I not sure but i think i have a small short in the 3.3v line because when with analog meter in scale of x1 black probe in gnd and red probe in one of the 3.3 atx line i have 600 ohm resistance but when i plug the vga cable one the vga port of the board there is no resistance mean a short i think,

I have a variable power supply that i use in the line of the 3.3v the only component that gets warm is the south bridge, is this meaning the component have the short?If so why the board still can turn on and display bios codes in the debug card stopping on the 13 20,

Can some one help me debug this, i whant to understand if the problem is in this component or not.

The debug card can tell me if the reset sinal is ok and i think that is ok because on the turn on the led lights one millisecond and then stays off meaning that IC super io resets south bridge and south bridge resets north bridge for the board to turn on all the devices.

Sorry for the long history, but i need some guidance,

thanks.

Regards, Diogo.

[piernov]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

If BIOS starts running, southbridge is mostly ok.
Also, if BIOS is running, reset signals are OK too (except maybe the DRAM reset).
On some BIOS, 20 means RAM detection error, so try with other RAM sticks and clean properly the RAM slots. We would need to know which kind of BIOS this is to know the meaning of this POST code.

[DsB_79]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

Hi, the bios is AMI, i have try clean out the slots and i measure 2.7v in pin 184 of the ddr i also try diferent ram sticks with no avail same error code.The mosfet near the ram slot has 3.3v on the drain but i see 2.7 in the pin 184, i also try remove the ram slot and see if the speaker beeps and it does, maybe you are just right the ram cannot be reset but i cannot find the fault component it can be pwm but i dont know how to measure the component.Thanks for the tip i apreciated.

Regards,Diogo.

[piernov]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

Ok on AMI BIOS this is not related to RAM. It doesn't really make sense for the BIOS to hang on code 20 here. I would say it is a dead BIOS or a dead northbridge (that you could try to heat/reflow to confirm).
At this specific point there should not be any communication with the southbridge, but you never know, it could be the culprit too.

Attached is the POST code list from AMI.

[DsB_79]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

Ok,i have reflash the bios but i dont know if has the correct one, can you try to explain how to reflash a bios to this board? I went to asrock support site and download the dos version file and then reflash this file to the bios chipset.

[DsB_79]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

Piernov i have heat the north-bridge and south max air max temp for 30 seconds in the back of the board wait a few minutes then turn on the board and the same error code 13 and then 20 i have a 4 digit debug card that gives me the previous stop code and the next stop code always stops on the 20 strange thing.


I have notice something in this following procedure:

With meter on resistance scale red probe on the orange wire 3.3v and black on the ground i notice some resistance increase maybe fill capacitor but when i plug the vga cable on port i see no resistance and i think that this is a short, what do you think?


Regards,

Diogo.

[ChaosLegionnaire]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

umm... how did u manage to reflash the bios if it wont even post properly or display anything on the screen?

when i plug the vga cable on port i see no resistance and i think that this is a short

then dont plug the vga cable in then and see what happens but i expect the post error code to still be the same because as u said the error code is the same even when u put the video card in or not. the post code 13 points to a chipset initialisation issue which must occur first before the video card can be initialised. the post code 20 says its waking from the s2 state... really odd code... did u try to clear the cmos as well? clear the cmos as well and see what happens.

[DsB_79]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

I have reset the bios, that was one of the first things i do.

With vga cable on port or off the post code is always the same.

I have reflash bios with williem programmer.

[DsB_79]

Re: ASROCK 775i65G Rev2.03 / Turns ON / No Display

Hi have try with another debug card and the code is 13 when vga cable is connect to on board port vga, with external vga card the code is 58 can someone tell what this means?

Regards, Diogo.