Electronic – Problem with molex connectors

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I have a 120V to 12V adapter with a molex end that I want to use to power a PC fan controller. However, the pins on the female molex (the 12V adapter) doesn't have holes that fit with the pins from the male molex (the PC fan controller molex connector). This figure shows the problem I'm having.
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Is this normal? From my understanding of molex connectors, the 12V adapter molex connector 12V ground pin is missing, and for the PC fan controller molex, the 5V ground pin is missing. Also, when connected like that, the molex connection would be in a 7V configuration. If I'm correct, the fan controller needs 12V + 5V to function correctly (which my 120V to 12V adapter is supposed to provide). So why both connectors pins are not correctly aligned?

Best Answer

Both manufacturers have assumed that whatever will be plugged into the other end of their connector will have both ground pins fitted & connected together (usually a safe assumption).
They therefore assume that they can save 1 or 2c on each unit by only fitting 1 ground pin.
Unfortunately for you, they each picked a different pin to fit.
If you have any access to the back of one of the connectors, you may be able to gently tease the ground pin out of the hole its presently in (you may need to depress/bend some little tabs on the side of the pin) and fit it back into the other hole such that it now lines up with its mate in the other connector.