This is how chips are numbered.
https://www.imagebam.com/view/ME8IINCIf see only 30 chips the problem can be:
Chip 30 - not weldet good
Chip 31 - broken or not weldet good
LDO voltage of domain with chips 31,32,33.
Check 5 test ponts voltage with test tool.
Why you changed heatsinks?!?!