Question Front dual fans stopped working. Questions about diagnosing them.

[otacon1]

I have a Corsair Graphite Series 780T case, and I just noticed the two front fans no longer work. Is it safe to try to measure the voltage coming out of the header on the motherboard with a voltmeter? Or is it too risky, since one accidental movement could short-circuit something? Or should I just go ahead and buy replacement fans? The motherboard is an Asus Z170-Pro.

What would you do? Thanks!

 

[Darkbreeze]

Try connecting either of those fans to any other motherboard fan header on the board, to see if they work there. If they do, then clearly it's the fan header that has failed. If they don't, then it's likely the fans.

Or, if you are using a fan hub that came as part of the case, then it very well might be that the hub it came with has failed which isn't surprising because those are incredibly cheap pieces of hardware.

 

[otacon1]

I connected the 4-pin fan header to a solderless breadboard and measured the voltages. It looks like the connector shown here https://allpinouts.org/pinouts/connectors/motherboards/motherboard-cpu-4-pin-fan/

The voltage between pins 1 and 2 read 7.6. The voltage between 3 and 4 read 1.7.

The fan connector is 3-pin. and was connected to pins 1-3 according to the site. It also has an LED. I also noticed sometimes the fans come on and then shut off again. The fans are single ones, with their own cords. At first I thought they were dual with one cord, since I didn't see the second cord.

The back of the fan says 12V. With the computer off, I connected the top fan to a 12V DC power supply between pins 1 and 2, and the fan came on. Connecting pins 3 and 4 to power turned on the LED. I tried wiggling the connect on the header, but it didn't make a difference.

Does that information mean the motherboard is going bad? It still works normal as far as computing goes.

 

[Darkbreeze]

I have no idea what you did, sorry. None of it was what I asked though, which, again, sorry, would be more helpful.

Are these fans connected directly to fan headers on the motherboard, normally, or are they, normally, connected to an integrated fan hub controller on the case? Or even a third party fan controller?