[SOLVED] NEW Gigabyte b550 Aorus pro doesn't boot to BIOS

[Mediumspecgamer]

Hi everyone,

I recently assembled a new pc from amazon.

Motherboard: Gigabyte b550 aorus pro
Processor: Ryzen 5 3500
16gb ddr4 3200mhz RAM (adata XPG)
500gb nvme ssd (kingston)
rx 580 graphics card
700 watt antec PSU
Antec 511mt cabinet

My motherboard doesn't boot even to BIOS, just a "flicker" of light on the aorus pro logo, and turn off in less than a second. Cabinet fans which have molex type connectors don't turn on either
8 pin + 24 pin power connector appropriately attached.

Things i have tried
1) Tested PSU - paper clip trick - working fine - PSU fans start fine - to be sure - replaced it - new one also tested similarly - the cabinet fans run absolutely fine with PSU -WITH PAPER CLIP ONLY!
When 24 pin connector is connected to motherboard - (rather than paper clip) - the cabinet fans don't start.

1. Reset CMOS - removed battery - kept aside for an hour, reset jumper pins - did not work - GOT A REPLACEMENT motherboard - still the same issue
2. checked front panel connectors - cabinet- tried removing reset switch (?endless reboot) - did not work
3. RAM modules are inserted fine - tried all slots - safely secured - no change
4. Graphics card attached properly - has 8 pin +4 pin requirement - attached...but even without it, the cabinet fans fails to start with the motherboard

Spoke to gigabyte - no help beyond resetting cmos.

Can someone kindly let me know how to get over this problem?

Note: The motherboard doesn't even BOOT to BIOS, just turns off immediately within a fraction of a second.
And PSU is working absolutely fine.

 

[popatim]

It sounds like you have a short somewhere and the PSU is shutting down to save the system.