Dell YRC3G Owner's Manual page 54

d Disconnect the following cables:
• SATA cables and ODD cables [1]
• USB 3.1 cable [2]
• Front system fan cable
• Flex0 and Flex1 hard drive data cable
NOTE: Do not pull the connector by the cable wires . Instead, disconnect the cable by pulling on the connector end.
Pulling on the cable wires may loosen them from the connector.
54 Removing and installing components