Asus PB50 Black screen after failed bios flashing

[Danfango]

Hi everyone, so I read through your troubleshooting guides and also I contacted Asus support but got the usual send it off to us as it's out of warranty and there will be a repair bill to pay.

 

Now after being a PC support technician for over 30 years I was hoping I could fix this myself, any help would be appreciated.

 

I have tried everything, jumpered clear cmos and tried holding the power button for 40 seconds etc etc still to no avail. Fan spins up and power button is on. But still a black screen on both HDMI and Display port connections using a known good cable and a working monitor. The only thing I haven't tried is removing the battery (if indeed there is one) as it's not visible on the top of the motherboard and I cannot find any schematics to tell me if the CMOS battery is on the underside before I start tearing the system down. Thanks in advance for any help and ideas.

[Average Nerd]

What exactly happened that made the BIOS flash fail?

Also, what model is your Motherboard? Forget that, misread PB50 as B550.

[Danfango]

Hi the electricity failed during the bios update

[DoctorNick]

9 minutes ago, Danfango said:

Hi everyone, so I read through your troubleshooting guides and also I contacted Asus support but got the usual send it off to us as it's out of warranty and there will be a repair bill to pay.

 

Now after being a PC support technician for over 30 years I was hoping I could fix this myself, any help would be appreciated.

 

I have tried everything, jumpered clear cmos and tried holding the power button for 40 seconds etc etc still to no avail. Fan spins up and power button is on. But still a black screen on both HDMI and Display port connections using a known good cable and a working monitor. The only thing I haven't tried is removing the battery (if indeed there is one) as it's not visible on the top of the motherboard and I cannot find any schematics to tell me if the CMOS battery is on the underside before I start tearing the system down. Thanks in advance for any help and ideas.

If you get a CH341a usb BIOS programmer, then you should be able to flash the bios. It must be in .bin format though, you might have to contact Asus to get that one. The CMOS battery is on the underside of the mb just like this PN50 most likely:

Guide flashing bios with linux:

https://winraid.level1techs.com/t/guide-how-to-use-a-ch341a-spi-programmer-flasher-with-pictures/33041

[Average Nerd]

4 minutes ago, Danfango said:

Hi the electricity failed during the bios update

If you can't flash to the BIOS chip directly for whatever reason, like @DoctorNick said, sending it in is likely your only option.

[Danfango]

Never used a bios flasher and a bit wary to do that, I see from numerous searches that a few people are wanting to know if the battery is on the underside, I might carefully try to remove the mobo to see if I can reset the bios by disconnecting the cmos battery. The mini pc is from 2019/2020 so not that old, are there any mobo's out there that do not use a cmos battery ?, oh and I also tried to get the mobo schematics to no avail.

[Blue4130]

14 hours ago, Danfango said:

Never used a bios flasher and a bit wary to do that, I see from numerous searches that a few people are wanting to know if the battery is on the underside, I might carefully try to remove the mobo to see if I can reset the bios by disconnecting the cmos battery. The mini pc is from 2019/2020 so not that old, are there any mobo's out there that do not use a cmos battery ?, oh and I also tried to get the mobo schematics to no avail.

Pulling or swapping the CMOS battery will not help. The bios is corrupted and needs to be reflashed. You either get the chip programmer or send it in.