Ремонт: Ноутбуков, Компьютеров https://vlab.su/ |
|
ASUS Z170-AR 1.03 Over Current Problem https://vlab.su/viewtopic.php?f=224&t=109004 |
Страница 1 из 1 |
oskar.walleij [ 12 ноя 2020, 17:02 ] | |
Заголовок сообщения: | ASUS Z170-AR 1.03 Over Current Problem |
Hi, I am new to the motherboard repairing and BIOS modding/debugging world. I started my Desktop System after a couple of weeks and found that the ASUS Z170-AR 1.03 motherboard was failing to boot with the following error message: Цитата: USB Device Over Current Status Detected !! System Will Shut Down After 15 Seconds. After downloading the "BoardView file" for a *similar* motherboard, I learned about the various OC (over current) detection sub-circuits present on the motherboard. I systematically checked the reference voltages present at all (4) of those voltage dividers and found them to be 3.26+ volts. Note: These voltage dividers ("sensors") are directly connected to the PCH. I also carried out the following debugging steps: - All of the USB ports are providing +5v and are able to detect the keyboard during BIOS POST (Caps Lock responds). They all *seem* to be OK. - The single USB-C port on this mobo is also providing power to charge things just fine. - I connected the USB keyboard to the PS2 port but the BIOS seems to be disabling all inputs when this 'USB OC' problem is detected. - All of the USB devices have been subsequently disconnected. - The cables for the front-panel USB connectors have been disconnected as well. However, the BIOS error about 'USB OC' persists . I then dumped the BIOS from the W25Q128FV BIOS chip (thankfully present in DIP-8 form factor) using "flashrom" on Linux. Цитата: $ sudo ./flashrom --programmer ch341a_spi -r bios_dump_another.rom flashrom v1.2-136-ged341cf on Linux 5.8.0-26-lowlatency (x86_64) flashrom is free software, get the source code at https://flashrom.org Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns). Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on ch341a_spi. Reading flash... done. This dumping process took around 2.5 minutes. The dump seems to match the "BIOS ROM file" which I extracted from the Z170-AR-ASUS-3801.CAP (downloaded from ASUS' website) using UEFITool. Note: This board uses the ASM1142 USB 3.0 chip which has its own over current (OC) detection. I couldn't find the BoardView for my Z170-AR 1.03 motherboard and hence I had to stop the hardware debugging process. Next -> I was able to patch the ASUS BIOS using UEFITool, GHIDRA, Cutter (radar2) and WinHex tools! After patching the BIOS, I was able to boot into the system! After logging in, I was able to confirm that ASM1142 chip is generating those OC (Over Current) signals. This controller can be disabled with the following command. Цитата: $ echo -n "0000:02:00.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind Now, I would like to fix this problem at the hardware level. I suspect that one of the capacitors has gone bad and is providing a low-resistance path to GND. This is a test system and I don't use it much. However, I would like to use this opportunity to learn and improve my debugging skills with your help. Thank you for your time and attention. What can I do next? |
aleksros [ 12 ноя 2020, 18:43 ] | |
Заголовок сообщения: | Re: ASUS Z170-AR 1.03 Over Current Problem |
The direction of repair is correct. For beginners quite a good level)) Thrown out an email for help. Describe in detail which element has no signal and which capacitor you suspect. Let's do everything else together. |
oskar.walleij [ 04 янв 2021, 11:31 ] | |
Заголовок сообщения: | Re: ASUS Z170-AR 1.03 Over Current Problem |
UPDATE (Jan 2021): This motherboard was lying flat on the table for the "operation" for a long time. Before starting the repair job, I blew hard on the motherboard with an air pump. After turning on this motherboard, the "USB Device Over Current" message simply disappeared! Crazy, right? I suspect that some dirt deposit(s) near the ASM1142 pins must have been causing short(s). These deposits must have gone away during the simple cleaning operation. Thanks for the help. |
Страница 1 из 1 | Часовой пояс: UTC + 4 часа |
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |