First AMD build not going well...

First of all, here are the specs for my new rig:

AMD Ryzen 5 7600X 4.7 GHz 6-Core Processor

Deepcool AK400 66.47 CFM CPU Cooler

ASRock B650M PG RIPTIDE Micro ATX AM5 Motherboard

G.Skill Ripjaws S5 32 GB (2 x 16 GB) DDR5-5600 CL28 Memory

Samsung 980 Pro 2 TB M.2-2280 PCIe 4.0 X4 NVME Solid State Drive

Lian Li LANCOOL 216 ATX Mid Tower Case

Corsair RM850x (2021) 850 W 80+ Gold Certified Fully Modular ATX Power Supply

These are all brand new parts.

So, after carefully hooking everything up, I switch on the PSU and get fancy rgb lights around the MB's chipset heatsink, but when I hit the power button on the front panel, nothing happens. No fans start up, no Post Status Checker lights come on. If I press the reset button, the rgb lights stop pulsing and stay the colour they were when I hit the reset. When I removed the front panel header and bridged the power pins with a screwdriver, nothing happens and I waited a good 15/20 minutes.

I've tried removing the RAM and putting them in one at a time in different slots, and nothing.

I've taken an old PSU (EVGA 750 G2) and its original cables from my old rig and put them into the new rig, and apart from the rgb lights coming on again, it just won't switch on either via the front panel On switch or by bridging the power pins.

I put the new PSU with its cables into my old rig, and nothing again. It suddenly wouldn't switch on via the front panel On switch or with the power pins being bridged. When I put the old PSU and cables back in to the old rig, it still wouldn't switch on. Bearing in mind, I built this rig back in 2016 and it's been utterly bulletproof from day one. 10 minutes with this new PSU and its cables, and it hasn't switched on since. I tried removing the CMOS battery for five minutes while pressing the power button on the case for 30 seconds and still nowt.

In the last few days, in between pulling the last few remaining hairs out of my head, I've breadboarded the new MB and just have the CPU and CPU cooler attached. Sadly there's nothing much happening when I bridge those power pins. Again, I've waited a good 20 minutes. I also bridged the clear CMOS pins and it didn't change anything. The only thing I haven't done on this MB is remove the CMOS battery as it's conveniently hidden underneath the VRM heatsink and looks quite difficult to get to.

Today I've taken off the CPU cooler and removed the CPU to check for any damage to the CPU and for any bent pins on the MB, and there's non as far as I can see.

Basically I've done everything here; https://www.reddit.com/r/pchelp/comments/eatxrs/perform_these_steps_before_posting_about/, apart from using a multimeter on the PSU. I'm not keen on doing that as I'm not a trained electrician and the wires are all black, rather than red/blue/yellow etc.

Any ideas, guys? I've only got until the 26th of August before I need to send the CPU, PSU, RAM and SSD back to amazon for a refund if they are dead. Honestly, I have no idea if they're dead or not. At no point have I heard any pops or bangs, nor have I seen any smoke or smelled anything burning. I'm around 60% sure the new PSU has nuked both the new and old rig, but I can't be 100% sure.

Any help would be very much appreciated. I've got no idea what to do now.

I agree with M440, see if you can pick up a cheap tester PSU to try with the old
rig you know was previously working. If it's still not working then RMA the board,
CPU, PSU, RAM etc. A modern PSU shouldn't be able to nuke a motherboard unless it
has a serious defect that bypasses all it's safeties.

Is it possible you confused the 8pin PCIe power for the 8pin CPU power cable? The
cable that goes to the motherboard should be a 4+4 connector not the 6+2. That
shouldn't short anything out but it will prevent the board powering up while
connected that way. Some modular PSUs allow you to connect the 8pin CPU power
cable to the 8pin PCIe power output from the PSU itself, the issue could be on
that end.

I doubt this is the issue as you say the old PSU now also won't power up the old
system but it's worth checking.

Xaltar wrote: I agree with M440, see if you can pick up a cheap tester PSU to try with the old rig you know was previously working. If it's still not working then RMA the board, CPU, PSU, RAM etc. A modern PSU shouldn't be able to nuke a motherboard unless it has a serious defect that bypasses all it's safeties. Is it possible you confused the 8pin PCIe power for the 8pin CPU power cable? The cable that goes to the motherboard should be a 4+4 connector not the 6+2. That shouldn't short anything out but it will prevent the board powering up while connected that way. Some modular PSUs allow you to connect the 8pin CPU power cable to the 8pin PCIe power output from the PSU itself, the issue could be on that end. I doubt this is the issue as you say the old PSU now also won't power up the old system but it's worth checking.

Sadly, I've only got until the 26th of August before I need to send the psu, cpu, and ram back to Amazon for a refund, even though I don't actually know if they are dead or not. So I won't have the time to get a cheap psu. I've checked the ssd in a laptop and thankfully it works fine. I've just no way of checking the cpu, psu, ram and motherboard.

I think I've put the right cables in the ATX12V1 connector on the MB. The ones that have cpu on them.

If it's of any help, I did take a quick vid of the system when it was still in the case. At this point it was hooked up to my old psu with the 10-pin ATXPWR1 connector detached from the psu, with the 18-pin still in the psu, as I wanted to see what would happen. There was one cpu cable hooked up to ATX12V1 but not ATX12V2, as I think you only need a power cable in there if you're overclocking the cpu.

https://drive.google.com/file/d/1m-uxmJ65QZzNWHqdHIUqj7lODm_EEzlG/view?usp=sharing

As you can hopefully see, some of the fans are pulsing on and off, apart from the two front intake fans, and the Post Status Checker leds (cpu and dram) are flickering on and off. When I connect the 10-pin connector up to the psu and switch it back on, I get the same pulsing rgb lights around the chipset and nothing more.

Have you checked the bottom of the motherboard for bent over component legs that
could be shorting etc?

Try connecting the board to the PSU with just the CPU and RAM installed, no connected
devices etc, just power. See if the symptoms remain the same. Also make sure there
are no other commonalities between the old system and new one, keyboard, mouse
etc.

Good luck.

Xaltar wrote: Have you checked the bottom of the motherboard for bent over component legs that could be shorting etc? Try connecting the board to the PSU with just the CPU and RAM installed, no connected devices etc, just power. See if the symptoms remain the same. Also make sure there are no other commonalities between the old system and new one, keyboard, mouse etc. Good luck.

Right now, I've got the new MB breadboarded on an anti-static bag on top of the MB's cardboard box with just the cpu and cpu cooler plugged in to the MB, with the ATXPWR1 cable fully plugged in to the psu along with the 8-pin cpu cable. No ram or any thing else.

When I switch the psu on I just get the pulsing rgb lights around the chipset heatsink. When I bridge the power switch pins I get nothing, and I've waited a good 20 minutes of so. If I bridge the reset pins, the rgb lights stop pulsing and stay whatever colour the were when I bridged those pins.