Question PC doesn't boot upon pressing power switch but flashes during PSU power on - Is it RAM, Mobo or PSU ?

[AdLibTact]

System
Mobo: B650M Aorus Elite AX v1.3
CPU: Ryzen 7 7700X
GPU: 1660 Ti
RAM: G.Skill Aegis 2 x 16GB (max 6000Mhz)
AIO: Thermalright Frozen Prism 360
Case: Montech Air 903

Installed Windows 10 Pro fine, activated EXPO profile 1 fine, didn't OC anything or touch any other bios settings.

3-day old rig was working fine 2 nights ago. I wanted to add a SATA SSD & a HDD so I connected them to the SATA ports. Mobo didn't light up (+ no post). I disconnected them, then mobo lit up with red DRAM light & "no signal" on monitor.

I reseated RAM & GPU, red DRAM & No Signal continues.

This morning, I took out ram, used eraser to rub the RAM & GPU inserts & used thin brush to ensure contact surfaces are clean.
Now the mobo doesn't even light up...

I ended up uninstalling everything from the case, & reinstalling everything to ensure all connections are correct & properly inserted.

I followed the stickied thread's instructions on everything, e.g. careful seating, connectors, GPU to monitor, flashed bios (no components, just mobo & cpu power connectors), extracted cmos battery + jumped cmos pins (always psu unplugged, both as an empty board, and with only cpu & AIO connected) etc.

Also tried solutions from YT like unplugging PSU & clicking pw sw for 30s, trying both ram sticks on each slot 1 at a time.

Did barebones set-up - CPU, CPU cooler, 1 ram stick & GPU (no iGPU), clicked switch (also tried jumping w screwdriver).
0 response from mobo despite flashing during PSU power-on

Have spent 20+ hours over past 2 days, would appreciate any help from anyone who has fixed this problem!

 

[rgd1101]

brand and model of the psu?

 

[AdLibTact]

brand and model of the psu?

Antec EAG 650W PRO Modular (Mobo, cpu & gpu power cords are attached to psu) I installed the 2 extra SATA drives (1 HDD 1 SSD) with 1 accessory drive power connector (so 1 connector for both drives) that can be added onto the back of the PSU). I searched 2 wattage calculators sites & both told me i'd need 450-500W, so i'd be extremely confused if it shorted my psu .-.

 

[JayGau]

Used an eraser to rub the ram and gpu connectors? Why did you do that? I understand you are desperate but this could have done way worse than good. The eraser can damage the gold plating on the connectors.

Your post is a little confusing and it's hard to know what the current state is. What does "0 response from mobo despite flashing" mean? Are the fans start spinning when you turn on the pc? Is the Prism 360 RGB light up? Maybe a video of what happens could help people here to figure out what is going on.

 

[Misgar]

This morning, I took out ram, used eraser to rub the RAM & GPU

I only do this as a last resort on DIMMs with very badly tarnished contacts or when the underlying metal pads have started to oxidise/corrode (happens in humid sub-tropical atmospheres). Rubbing the gold contacts could generate hundreds or thousands of Volts, leading to permanent ESD damage. Not a good idea for static sensitive RAM or CPUs,

I disconnected them, then mobo lit up with red DRAM light & "no signal" on monitor.

In isolation, I'd say the mobo was objecting to the 6000MT/s overclock if that's the speed you were using. AMD recommend maximum DDR5-5200 on the 7700X. Anything higher is not guaranteed by AMD, but down to the Silicon Lottery, the quality of the CPU/RAM/BIOS and any manual tweaks you make to RAM timings. Did you run a full pass of MemTest86 (several hours) to confirm stability with the XMP 6000MT/s overclock? No telling if it really was stable otherwise after only 2 days.

I installed the 2 extra SATA drives (1 HDD 1 SSD) with 1 accessory drive power connector (so 1 connector for both drives) that can be added onto the back of the PSU).

Could you be a little more specific about the "accessory drive power connector"?

Was it something like this Corsair modular SATA power cable?

Or was it a cheap-and-cheerful SATA splitter/adapter cable, which sometimes catch fire due to short circuits inside the moulded SATA housing?
https://nerdtechy.com/best-lp4-molex-sata-power-adapter

flashed bios (no components, just mobo & cpu power connectors),

I've been fortunate and never never had to do this. I'm fearful that something might go wrong and I wouldn't be able to see any error messages on the monitor. If the BIOS worked for 2 days before fitting the SATA drives, I don't think it was the problem.

Have spent 20+ hours over past 2 days, would appreciate any help from anyone who has fixed this problem!

After everything you tried, it's difficult to guess what has gone wrong. It all started when you connected the SATA SSD and HDD. That shouldn't be a problem. I have some PCs with 10 SATA HDDs and SSDs, but your system hasn't recovered from connecting two drives.

I normally grab a spare system with similar components and transfer parts over from the bad system, one at a time.

I'd probably move the RAM over first, because it's the easiest option. I'd test it at stock JEDEC 4800MT/s with MemTest86. No need to try XMP 6000MT/s. Just make sure the RAM passes MemTest86.

I'd move the GPU over to another PC and see if it works. A slight risk, but it's probably OK.

Next I'd use a multimeter as a quick test on the PSU, but only to confirm the +3.3V, +5V and +12V rails were present. Then I'd fit the PSU in my oldest, least important, most expendable PC, cross my fingers and switch on. No point killing an expensive PC with a bad PSU.

If I felt the risk worth taking, I'd transfer the CPU to a compatible motherboard and switch on.

For the next test, I'd fit a known good CPU in the suspect motherboard. Again, it's a slight risk.

On to the SATA SSD and HDD. I'd attach these, one at a time to a very old sacrificial PC. If the drives are deadm they could take out the PSU or mobo.

By now the bad component(s) should have been identified.

Assuming you don't have a spare system, is there a local computer repair shop nearby? Another option is to start buying replacement parts which could get very expensive. You stand the risk of further damage if you buy new components, or move parts which may already be damaged to a new system. Finally there's the new PC solution, but hardly desirable.