[SOLVED] No post with a different CPU!

[CFFA17]

Specs:
I have a Dell optiplex 390 with 2x4gb DDR3, Sapphire Nitro R9 390, i5 2400, 1x 500GB HDD, 1x 1TB HDD, and a 550w power supply running Windows 10 Pro and A14 BIOS, which appears to be the newest version for the motherboard. Luckily I've been able to shovel these parts together for under $200. Point aside, the computer is normally connected via Display port to a 1080p144hz monitor.

Issue:
After changing the CPU to an i7 3770, the computer no longer posted, booted, beeped, or displayed. It only turns on for one flat second, and then turns off for 3-4 seconds. After about 15 minutes of repeating the cycle, the fans spool up to operating speed and I can hear the hard drive running, which causes me to think the computer is on.

Jumping some power switch pins causes the cycle to stop.

Likely unrelated info: The computer case power switch does not power the computer on and is well known to become a stuck open circuit. The PSU switch turns on the computer just fine.

Currently tried solutions:

I've removed the CMOS battery for 30 seconds with the PSU switched off.

I've switched PSU on with and without the CMOS jumper and/or battery.

I've disconnected one stick of RAM and powered on, then the other, then shuffled one around, then both. No ram gives the typical 1-3-2 beep of "no memory" (what a surprise)

I've removed the GPU, running HDMI and VGA to a monitor, then powered on waiting for the cycle to stabilize, and still no input to the monitor.

I've connected a different GPU, running HDMI and/or DVI to a monitor, still no luck.

Bad CPU? Not likely. The seller told me he started his computer just fine with it in his computer.

¯\(ツ)/¯

Maybe I'm just small brained and somehow have the wrong socket or something stupid like that... but please throw any solution my way so I can get this CPU working in my computer!

 

[XxDarkMario20xX]

Sorry but think Your MB cant run the i7 cpu only the i5 acroding to this website about your desktop but we need to know more information about your motherboard because it uses the same socket 1155 but I do not know if the i7 can run on that motherboard! You might need to do Bios updates!

Acording to the Mods on Dell Forums this is about other cpu but think its the same to every cpu above i5

Dell only ever shipped the 390 with CPU models up to the i5-2400 so it was never validated and can't be 100% guaranteed to work. If you are going to upgrade, I would advise updating the system BIOS beforehand.

https://www.dell.com/community/Optiplex-Desktops/390-CPU-upgrades/td-p/5975479

 

[Nemesia]

What is your DELL exactly? You say 390 but there is no A18 Bios for the 390. It's for the 960.

 

[CFFA17]

Sorry but think Your MB cant run the i7 cpu only the i5 acroding to this website about your desktop but we need to know more information about your motherboard because it uses the same socket 1155 but I do not know if the i7 can run on that motherboard! You might need to do Bios updates!

Acording to the Mods on Dell Forums this is about other cpu but think its the same to every cpu above i5

Dell only ever shipped the 390 with CPU models up to the i5-2400 so it was never validated and can't be 100% guaranteed to work. If you are going to upgrade, I would advise updating the system BIOS beforehand.

https://www.dell.com/community/Optiplex-Desktops/390-CPU-upgrades/td-p/5975479

Another BIOS update might fix it, and in the setup I see a UEFI and Legacy boot sequence option. I'll switch to UEFI, boot, and then update on the results. After reinstalling the i5 it gave a CPU microcode update failure so that sounds like it might have something to do with the BIOS. I'm not the first one out there that has built a 390 for gaming so hopefully others can learn from this.
Update: switching to the UEFI and booting gives "no bootable drive", using legacy from here on.

 

[CFFA17]

What is your DELL exactly? You say 390 but there is no A18 Bios for the 390. It's for the 960.

Apologies, You're right. A14 BIOS with service tag 9LYVGS1. I used to use a 960 SFF that I quad core swapped so my brain swapped the number.

 

[CFFA17]

Currently attempting BIOS flash/update via USB
Maybe reinstalling it might work

 

[SamirD]

Another BIOS update might fix it, and in the setup I see a UEFI and Legacy boot sequence option. I'll switch to UEFI, boot, and then update on the results. After reinstalling the i5 it gave a CPU microcode update failure so that sounds like it might have something to do with the BIOS. I'm not the first one out there that has built a 390 for gaming so hopefully others can learn from this.
Update: switching to the UEFI and booting gives "no bootable drive", using legacy from here on.

So the bios update will probably need the legacy booting on, but once you do the update, you will need to switch back to uefi to boot from your drive since it was probably not installed legacy.

But before hooking up the drive or cpu. I would reboot to bios, make sure your current processor is installed and confirm your bios version. Then I would swap your processor and simply try to get to the bios again. Then switch to uefi and then try to boot from your drive. One step at a time...

 

[CFFA17]

Sorry but think Your MB cant run the i7 cpu only the i5 acroding to this website about your desktop but we need to know more information about your motherboard because it uses the same socket 1155 but I do not know if the i7 can run on that motherboard! You might need to do Bios updates!

Acording to the Mods on Dell Forums this is about other cpu but think its the same to every cpu above i5

Dell only ever shipped the 390 with CPU models up to the i5-2400 so it was never validated and can't be 100% guaranteed to work. If you are going to upgrade, I would advise updating the system BIOS beforehand.

https://www.dell.com/community/Optiplex-Desktops/390-CPU-upgrades/td-p/5975479

As you have said it was never shipped with the i7 option and never got a BIOS update allowing for the i7 for this reason. Destroyed my motherboard today and am buying an Asus one which is confirmed as compatible.