One of the more common problems with mini PCs is instability and sudden rebooting. We’ve seen this ourselves with a few mini PCs we have on our bench. Often, the instability is blamed on the device but it’s well worth checking out the power supply you’re using to power it.
PSU (power supply unit) issues are more common than you might think. That’s because not all PSUs are rated at the right power levels to keep your mini PC powered up.
This is particularly true if you start trying to load up the mini PC’s USB ports with external devices, expecting it to supply power to each device. With many mini PCs coming with basic 5VDC/1A PSUs, you’re likely to run into problems with just a couple of peripherals plugged in.
We’ve also seen one PSU on a mini PC that was supposed to be rated at 900mA but struggle to keep a single-core mini PC up and running consistently. When we changed that PSU over to a genuine 5VDC/2A unit, the mini PC was as right as rain.
And it’s not just limited to mini PCs – one budget tablet we purchased came with an AC mains PSU but when plugged into the tablet, the tablet became unusual – tapping letters on the Android keyboard would just result in gibberish. But as soon as we connected it to a PC-based USB port, it was perfect. The problem? A poor-quality PSU that created too much interference that caused the capacitive touchscreen to not work correctly.
So what’s the solution? First thing, make sure you use a 5VDC/2A PSU on any mini PC – dual-core and quad-core models need more power than a basic 5VDC/1A PSU can deliver. The second thing is to make sure you use a quality PSU too – avoid the cheapo ones whenever you can. Electronics stores often carry these better models and you can pick them up for under $20. The Apple iPad PSUs that deliver 5.1VDC@2.1A are excellent and they’ll happily power any USB-voltage powered mini PC.
If you have an old smartphone that has a 5VDC/1A PSU, keep it for your single-core mini PCs like the MK802 or CX-01 models.
And finally, make sure you use a powered USB hub wherever possible for your external peripherals – don’t make the mistake of expecting your mini PC’s PSU to power everything you want connected in. A good powered USB hub should have its own PSU and ideally, it should be rated at 5VDC/3A. You can find universal 5V/3A PSUs again from electronics stores for around $25 that will provide enough power to handle bus-powered USB hard drives.
The key to powering up these devices is to ensure your PSU has sufficient current reserves to deliver the in-rush or ‘start-up’ current these devices need to get going. Portable hard drives for example require more power at the start as they accelerate the main spindle motor up to speed. But once there, the power requirements drop back. This is another reason why smaller 5VDC/1A PSUs will sometimes work in some applications, yet fail in others.
So the trick is, make sure your PSUs are large enough to handle the job you need them to do – that means knowing the power consumption ratings of the peripheral devices you want plugged in.
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