HP Z230 workstation (SFF) boot problem

[Mosfin]

My HP Z230 SFF workstation stopped booting, It gives single beep, blue led lights, fan spins, the green led lights then goes off, it shuts down and after 2 seconds repeats the above, forever.

The screen is black (i don't see any error nor boot selftest), the keyboard is connected to usb port, the only device controller card i have is Nvidia Quadro K620. 

What can i do??  I appreciate any help.. 

[DGroves]

first do a "DIST" test on the power supply (read service manual) if supply passes test try a sec video card  if still nothing replace board or entire system

https://support.hp.com/us-en/product/hp-z230-tower-workstation/5367825/manuals

https://www.manualslib.com/products/Hp-Z230-Sff-Workstation-3226753.html

z230 replacement board is around 30/40 us dollars on ebay

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2512315.m570.l1313&_nkw=hp+z230+motherboard&_saca...

however a z240 motherboard which has the same rear I/O layout can be used instead of a z230 board,  if you go this route you also need the z240 power supply (approx. 30.00) a cpu (price depends on speed) and ddr4 ram

considering a complete z240 system is around 100/150 us dollars i would simply buy a complete z240 as it supports nvme booting and is quite a bit faster than a z230

[Mosfin · Accepted solution]

Problem resolved after i removed all memory DDR3 

dimm cards, and plugged them back. 

It worked only after i repeated the above few times. and i thought computers is exact science..

Thanks anyway.