Hi, HP's "beep decoder" document is here:
https://support.hp.com/gb-en/document/c03599666
Four beeps = a problem with the power. Unfortunately they don't offer further debugging steps. Thermaltake are well known, quality brand so I expect your new PSU is fine.
When your old PSU died do you think that there is a possibility it fried something on the board at the same time?
Thanks for reply Sir .I read manual and check all thing in board and fixes all issue removs all devices but not fix issue without hdd working perfectly.but I connect power wire in hdd or and DVD no sata wire only power wire .and problem show me .I uploaded my PC issue video here plz check Andy Sir.i update already new bios this Version: 3.61 Rev.A Release date:Mar 6, 2018.my board Rev: 003
https://support.hp.com/us-en/drivers/selfservice/swdetails/hp-z800-workstation/3718645/swItemId/wk-207280-1 (https://support.hp.com/us-en/drivers/selfservice/swdetails/hp-z800-workstation/3718645/swItemId/wk-207280-1)
https://vimeo.com/346544447 (https://vimeo.com/346544447)
Compare the pinouts of the adaptor leads with the HP documents and ATX standard. I bought them leads and the PS_OK and 5Vsb pins were reversed. You should also disconnect the 5V between the motherboard and the power supply, that should not be connected. The motherboard generates it's own 5V and what the lead is doing is connecting that to the power supplies 5V output.