820-00609 - iMac18,3 - 2017 - 27" - only Apple logo / no progess bar / no bootpicker possible

[quasimodo]

Hey guys,

whats going on with this machine?

Can do only SMC-RESET. Only Apple Logo and chime.

Option Key not working, no recovery partition, no hardware-test, nothing is working. Cant open bootpicker via option-key. No progress bar. Not booting at all. No safe mode possible...

 

[2informaticos]

What exact MLB do you have there?
What the client said about the failure has appeared?

 

[quasimodo]

just like that. need to open the machine for the mlb code....

 

[2informaticos]

How do you want to repair then?

Is the Google blocked on your place?

iMac18,3 - 2017 - 27" motherboard - Google Search

 

[quasimodo]

820-00609 is the code.

all diagnostic LEDS are on. no SATA Drive, only blade ssd

 

[2informaticos]

Did you try to connect the keyboard on all USB ports?
Also consider to test with another keyboard.

 

[quasimodo]

yes. tried every port. keyboard is working.

 

[2informaticos]

If you disconnect internal SSD, doesn't boot from USB?

Just in case, try known good BIOS.