How to install a fan in the LOGITECH Z906 speaker system?

[helgehelge123]

Hey guys, 
I recently bought the Z906 home cinema system from logitech but its getting pretty toasty in the subwoofer box (mainboard etc.)

Now I took it apart and was looking for some low voltage power source for a noctua fan (5v or 12v) and i found a weird looking connector, which doesnt quiet fit a fan plug and it provides 45 volt. does somebody know why this is there? or do you have an alternative power source?

[Guest Generallee]

You really should not be poking around in there, your best bet would be using an external 5v power supply to not interfere with the sub's power delivery. 

[ItsTheDuckAgain]

24 minutes ago, Generallee said:

You really should not be poking around in there, your best bet would be using an external 5v power supply to not interfere with the sub's power delivery. 

this

[aezakmi]

If it's 45V you could use it but you'd need some transistors, maybe a fuse, and a resistor

 

I'd go for the easy one, get a 120/240V to 12V transformer (not power supply as it's smaller and internal) and connect the fan to it, done.

 

Problem: fan spinning even if the board isn't working

Solution: add a switch to turn off the transformer

[unknownmiscreant]

I would caution against adding additional load to anything on the main board. Any power supply rails you find may not be designed to handle the extra load of a fan. This could cause some very strange behavior later on. Personally I would take a USB phone charger apart and use the 5v rail from that to run the fan. Connect it up to the mains rail in the sub woofer, and turn it on and off using the 45v rail (although I would suspect this is more along the lines of +/-22.5V for power amplifiers) with a low coil current relay.

 

Running the relay off the 45V rail is likely going to be fine as it will only draw a few mA and the rail should be desinged to supply at least an amp or two to the power amplifiers.