Repeatedly getting system errors for defective fans. For example,
Fan 6A is either removed, incorrectly installed, or not present.
Fan 6B is either removed, incorrectly installed, or not present.
This may be caused by loose connectors or a failed fan canister
The connector for the fans in the head may work loose from the motherboard after shipment or over time in the heating and cooling cycles. The most common fix is to reseat or swap the fans.
There are multiple fans installed in the head units to move the air needed to cool the cpus and RAM. There are two fans in a canister and there are eight canisters in a head unit. The fans are labeled next to each fan. The following YouYube video explains how to replace the fans in a Dell R640 (https://www.youtube.com/watch?v=02X3f5mittw). This is the procedure to either swap or replace the fans in a fan canister.
The basic steps are:
Note - This article was written for a sensor which had the fans dropping and coming back. The fans were removed and reinstalled and they worked. For several months. Then they started failing again. They have now been replaced because the reset/swap did not cure the problem long term.