No display signal on newly built PC

[tuxius]

I try to assemble my new PC but there is no display signal. My hardware is:

 

- MSI Z370 TOMAHAWK

- Intel Core i5-9600K 3700 1151V2

- Gain8GB D6 RTX 2070

- Enermax MaxTytan

- XILENCE CPU-Kühler I402 Perf. C-Series

- Tt Versa H23 Window

 

I already did google a lot and tried a lot without success:

 

- tried only one RAM dim in all slot and all combination

- tried a different monitor and all different inputs

- tried the minimum setup on my desk without the case

- bought a speaker (InLine 59910 Mainboard Testset), but no error beeps (only w/o any RAM)

- bought a second motherboard (Z370 PC PRO, LGA 1151), did not work either, tried everything above, still does not work

 

The second mainboard has 4 debug leds indicators. Non indicates shows an error. Only if I remove all RAMs the speaker beeps and the RAM led indicates.

 

Any advice highly appreciated - I have no clue!

 

Attached some picture with the second mainboard

[.Apex.]

@tuxius

you need to update your BIOS for your Z370 board to support 9th gen CPU's, and you can only update the BIOS with 8th gen CPU's, so if you can borrow a CPU from a friend or take it to a PC shop they'll update the BIOS for you.