Thread: FAQ: How to Wire an OPUS PSU

note: This is meant as an addendum to Bugbyte's Powering your Car PC when it's not in the car post.


Basically this is how I connect a spare desktop power supply to my opus for testing standby/hibernation/startup while not hooked up to the car.

Just make sure the power supply is up to the job, and that the power supply is turned on (green/PS_ON lead on ATX connector (pin 14) shorted to any black/ground).

Close the switch to simulate an "ignition on" in the car, and open the switch to simulate an "ignition off" in the car, which will start the delayed shutdown/hibernate/standby.


I don't know the pinout of the power input connector on other opus psu's, so you might have to rewire appropriately for your model.





also, for OPUS ITX MINI case owners, make sure to screw in the top cover before powering on the system. The power supply is grounded to the top cover, and unless the cover is screwed in an connected to the other piece (that the motherboard is grounded to), it can be a cause for problems like not POSTing and giving you a Bad Power Supply beep code.

good job I added it to the first post.

This is a very good FAQ.

FUSES. You want to always fuse as close to the battery as possible...and as close to the power you plan on pulling without going too far over. Why? Obviously if it is unfused or has a ridiculously sized fuse then a direct short will turn your battery/wire into a light bulb for a while until the engine bay catches fire.

If you have a fuse too large, your cabling will be OK, but if you have a malfunction on the board, that circuit board will now become the source of fire...and you will get a fire in your dashboard.

You want the fuse to blow EXACTLY when it is needed...and not so early that it blows every other day.

The OPUS 120 has a built in 15A fuse right at the power entry...there is no need to put a larger fuse on the line from the Battery to the board.


DISTRIBUTION BLOCKS...for audio equipment...if you have them hooked to different grounds (due to using the vehicle chassis as the wiring) you can get the problem known as Ground Loop. The symptoms are noise/hum in your speakers. The best answer would be to run some nice welding cable to your amp racks from the negative battery terminal and use a giant distribution block to feed ALL your components from...no you don't need a fuse because if the grounding wire touches the chassis...there is no voltage potential...so no problem (the are the same electrically)

I have all my amps running from the same chassis ground, and everything else from separate grounds...I run no filters, and have no noise in the stereo...(however I do get computer noise in my ham radio...but that is a different story)

This FAQ is so good that the newbies are postin their wiring questions in it.
For this reason I'm closing this FAQ thread.

We really do ned to make the FAQ Emporium a moderated forum.