PC Processors

[RPX100]

MB: MSI B550-A Pro (tried 3 different BIOS versions)

CPU: AMD Ryzen 7 3800XT

GPU: RX 5700 XT

RAM: GSkill 3600-CL16 32GB dual kit

PSU: 650W (also tried 750W from other working PC)

Problem: New PC build will not POST.

Can not enter BIOS (no signal on monitor connected to RX 5700 XT)

MSI EZ debug LED will stay white on "CPU"

1) removed everything but the CPU, which resulted in 3 long beeps (RAM missing) and DRAM LED blinking.

- there are no beeps when RAM is installed (only CPU debug light stays ON and white)

2) reinstalled 1 RAM modul: CPU debug light stays on white (no beeping)

- switched to other RAM modul: CPU light on again

- tried another RAM modul out of my working PC: same result

3) took the MB out of the case again, reconnected all power cables and tried again on the table: same result

4) tried new 650W power supply and old 750W power supply (same results)

5) tried 3 different BIOS versions (factory shipped, MSI recommended and latest memory support update)

- tried CMOS reset

I have build 5 PCs over the last 10 years. (for myself and family) ...

Never had to deal with a build that wont even POST at all.

If anyone can point me towards other things to try, that would be awesome.

Any suggestions on how to find out if MB or CPU might be bad/broken?

local shops are closed: everything was ordered online - so it would take some time to replace MB and/or CPU

Thank you!

[rurouni51]

Hi RPX100,

A friend recently had this issue, it turned out he had bent a PIN while inserting the CPU, have you removed the CPU to check?  Also, try simply re-seating the CPU.

[RPX100]

@rurouni51 hey there, thanks for the reply.

I reseated the CPU just now and looked at the pins with a magnifi-glass: all pins are in top shape.

Socket looks clean and in top shape too.

Still no POST and CPU debug LED after reseating the CPU.

[rurouni51]

That's a shame it wasn't an easy fix.  Seems like the MBD or CPU are DOA.  Do you know anyone with a compatible MBD/CPU you can test?

[RPX100 · Accepted solution]

Update: cleared CMOS again with 1 RAM module installed in the first memory slot

-> according to manual this is the wrong slot for single memory module (DIMM_A1)

... but I got it to POST now and after checking all the BIOS settings I got it to boot and POST now

with both 16 GB memory modules installed (2x16GB - 32 GB total) set to 3600-CL16 and working perfectly.

---

So in conclusion: I do not know why the System was not booting, but clearing CMOS with

only 1 memory module installed (in the very first slot DIMM_A1), it worked and after changing some

BIOS values, it also worked with intended dual channel setup (DIMM_A2 and DIMM_B2)

- consider this topic solved and closed ^^

[julbo93]

Hey i know your Post is more than 2 years, but i got the same problem as you. Do you still know, hat you changed in bios to run your RAM Stick on Dimm A2 and B2?

[RPX100]

@julbo93 hey there.

I already marked my steps (from back then) as the solution to this topic.
What I did was a complete reset to default values for the latest BIOS (back then).
I was not able to enter the BIOS - so it was done by CMOS reset.
- so in my case: all values were "AUTO" or "DEFAULT"

I also remember that there were initial problems with the M.2 drives.
So it might be useful to disconnect all drives from the mainboard,
until the system boots into BIOS and then change "some values"
(whatever is necessary to make the system work with your setup)
- leaving everything on "AUTO" or "DEFAULT" should work in most cases.

There was no specific setting that worked for me.
The system was just generally messed up before the initial boot sequence was working.

[julbo93]

so you mean enabling stuff like XMP, SAM and so on? Wasn't there any special thing you think that worled pretty well for you? Don't want to go single channel longer than needed due to performance loss

[RPX100]

maybe this topic can help you ... wrote down all my questions in that one.

Currently running XMP disabled and frequency pre-selected via BIOS.
SAM is on (RX 5700 XT) and I do not use PBO right now.

Everything else is already explained within this topic here.
Nothing else I can tell you.
I already wrote what solved the initial problem in the post marked as solution.