Question Dell Inspiron 27 7775 stuck on Self Test Feature after BIOS update ?

[Cloudy7]

Hey All,

I've got a Dell Inspiron 27 7775 that won't boot and is stuck on the Self Test Feature Check (Red, green, blue, black, white screen). I had recently re-installed Windows 10 (20H2 update) on it and was updating the Dell drivers in order to try to fix an issue with the integrated webcam not being detected (A known issue with this model on later Windows 10 versions).

I ended up downgrading the BIOS to earlier versions, until I went to the very first one. Once I installed that version it restarted and was then stuck on the STFC and I can't get out of this. Really kicking myself because of this.... 😓

Rebooting the machine does not bring up the usual DELL screen and tapping ESC or any of the F1 - F12 keys doesn't trigger the boot menu so I can't get into BIOS or any diagnostics at all.

I've pulled this thing apart and checked all the cables from the system (IO) board, which then connects to the motherboard, and have reconnected/reseated everything I can see.

This AIO allows you to switch between PC mode and HDMI (monitor) mode (To be used as an external monitor for another connected device) so I can still use it as a monitor, there's a 5-second window after powering it on where I can quickly toggle to this mode but after that, it's stuck on the STFC.

Does anyone know if there's any way to get past this SFTC? I've tried to follow some of the ways from the Dell site here (Most of them are for other Dell standalone monitors), but no luck.

Really hope I haven't bricked the motherboard just because of downgrading a BIOS version.. I've checked online and the motherboard for this model is hard to find as most places are out of stock too... most likely due to supply constraints like all other manufacturers I assume...

Sorry for the long read, happy to hear your thoughts.

 

[Vic 40]

Seems that removing the battery from the motherboard does a clear cmos as usuall, so remove for 10 minutes to be sure and see if it helps.

Think you might already have it, but maybe usefull for maintenance,
https://dl.dell.com/topicspdf/inspiron-27-7775-aio_service-manual_en-us.pdf

 

[Cloudy7]

Hi Vic 40, thanks for the reply.

I did replace the CMOS battery with a brand new one, but I didn't do what you mentioned and leave it removed for 10 minutes or so.

After reading your message I decided to give that a shot, left the CMOS battery out for the whole day (8 -9 hours after coming back home from work), so when I placed it back in there's no change.

Yep that's the same manual I have too, thanks for also providing that anyway!

 

[Vic 40]

Wonder if first bios doesn't support the cpu (or other part) you have now in some way. Not alot else i can think of.