Laptop does not post, all voltage rails present, powers on

Hello there! I have an ideapad 320 laptop and it does not want to post. Fan spins for a few seconds then stops. No display backlight either. It previously had a dead pmic (pu501) which has been replaced now. All power rails seem to be working, nothing seems to be shorted on the board. It takes around 50mA from charger. I tried removing cmos battery and putting it back in. I'm considering flashing the bios via a usb programmer board, but that'll take a while to arrive. Is there anything I can try? Thanks.

回答此问题 我也有这个问题

这是一个好问题吗?

得分 3

5条评论:

I have the exact same issue. Did you manage to fix it?

完成的

Hello! Unfortunately, I wasn't able to fix it. the next few things I tried were to replace the EC and reflash the bios using a ch341 board, to no avail. I stopped when I learned that some EC chips have to be programmed and I don't have the tools for that anymore. I thought the CPU is dead but I doubt it as it was only very slightly warm, and none of its rails were shorted. A bad GPU can be a cause, but at that point I just gave up because it isn't a good laptop to begin with. Terrible plastic build quality, bad cooling performance, insufficient IO protection against voltage spikes, and proprietary parts (if i recall correctly pu501 calls for an LV5028 chip which is proprietary and unobtainable. my only hint of hope was a note in the schematic indicating an LV5075 can be substituted as long as an APL5930 circuit was soldered and configured with jumpers. I got this circuit to output the 1.05v required for the GPU but it didn't boot anyway. BS). Best of luck.

完成的

@luna9 Hello too. I got this issue after using an utility to unlock the advanced BIOS settings, and change a wrong setting. Already tried removing the CMOS battery which did not work. I still have hope for the CH341A programmer. Is the BIOS chip near the battery? I see a chip that looks like a BIOS chip.

完成的

I flashed the BIOS chip using the programmer. But now, the laptop turns on with a black screen, and then turns off. This keeps repeating. How could I fix this?

完成的

GUESS WHAT? I FIXED IT! You must not flash the BIOS ROM grom the uodates, but someone else's dump. Try the BIOS file dump from this thread and flash it to the BIOS chip with a programmer:

https://www.badcaps.net/forum/showthread...

完成的

添加一条评论