If you are reading this, chances are you are staring at a green Dell motherboard pulled from an OptiPlex 390, 790, 3010, or 7010. The model number stamped on the board is MIH61R (often paired with a CN-0Y2MRG or similar tag). You have a standard PC case sitting next to it, and you are holding a handful of tiny two-pin connectors labeled Power SW, HDD LED, and Reset SW.
Power Switch Orientation: The power switch (Pins 5 and 6) is not polarity-sensitive. It will work regardless of which way the connector is flipped. dell mih61r mb front panel pinout
Row 1 (Edge): 1=HDD+, 3=HDD-, 5=GND, 7=Reset+, 9=Reset-
Row 2 (Inner): 2=PWR+, 4=PWR-, 6=NC, 8=PWR_LED+, 10=PWR_LED-
Mark grabbed his multimeter. He needed to be sure. He set it to continuity mode. He touched the black probe to a known ground on the chassis and the red probe to the pins he suspected were ground. The Ultimate Guide to the Dell MIH61R MB
Now that we've covered the Dell MIH61R front panel pinout, let's discuss how to connect the front panel headers and peripherals. Here are some general guidelines: Front panel header location and orientation
motherboard, here is the pin-by-pin breakdown for your front panel connections: Pin Mapping Table Pin Number 1 Positive (+) 2 Positive (+) 3 Negative (-) 4 Negative (-) 5 Power Switch 6 Power Switch 7 Empty (No Pin) 8 Unused / Reserved Key Installation Notes