I have an internet/work machine that I use for serious tasks and therefore have a lot of devices occasionally hooked up to it:
Digital Camera, SatNav, USB drives, MP3 player etc.
What I didn't realize is how important it is to make sure you think about which devices are fed by the +5vsb feed that still hangs around when the PC is switched off!
I've always jumpered motherboards to supply 5vsb to the PS2 mouse and keyboard so I can have the option of powering on my PC without hitting the case button. I also left the jumper that supplies the same voltage to the back two motherboard USB sockets for the same reason.
Problem is I never thought about this when I decided to use a PS2 keyboard and mouse, leaving the back two USB ports providing a +5vsb.
What's the problem you ask?
Well, I happened to have my Satnav and MP3 player hooked up to these ports, so they were getting charged when the PC powered down. At first I thought it was a neat feature....
...until my PSU's +5vsb line began to exhibit signs of failure/damage. It's rated for 2A, but is now fluctuating (as shown by the flickering motherboard LED) causing random cold boot issues. It took me ages to track down the issue as it was so subtle, but now I've replaced the PSU all is well.
The voltage regulator for this rail must have been damaged, as it's usually on an independent circuit. The rest of the PSU is fine so it's an annoying issue as it powers the PC from warm boot without any problems - and it was quite a reasonably priced unit!
I've since jumpered the motherboard to avoid supplying external sockets with +5vsb and will use the case power switch from now on, just to be safe!
Just thought I'd give you guys a heads up about potential issues with +5vsb and USB sockets.
Digital Camera, SatNav, USB drives, MP3 player etc.
What I didn't realize is how important it is to make sure you think about which devices are fed by the +5vsb feed that still hangs around when the PC is switched off!
I've always jumpered motherboards to supply 5vsb to the PS2 mouse and keyboard so I can have the option of powering on my PC without hitting the case button. I also left the jumper that supplies the same voltage to the back two motherboard USB sockets for the same reason.
Problem is I never thought about this when I decided to use a PS2 keyboard and mouse, leaving the back two USB ports providing a +5vsb.
What's the problem you ask?
Well, I happened to have my Satnav and MP3 player hooked up to these ports, so they were getting charged when the PC powered down. At first I thought it was a neat feature....
...until my PSU's +5vsb line began to exhibit signs of failure/damage. It's rated for 2A, but is now fluctuating (as shown by the flickering motherboard LED) causing random cold boot issues. It took me ages to track down the issue as it was so subtle, but now I've replaced the PSU all is well.
The voltage regulator for this rail must have been damaged, as it's usually on an independent circuit. The rest of the PSU is fine so it's an annoying issue as it powers the PC from warm boot without any problems - and it was quite a reasonably priced unit!
I've since jumpered the motherboard to avoid supplying external sockets with +5vsb and will use the case power switch from now on, just to be safe!
Just thought I'd give you guys a heads up about potential issues with +5vsb and USB sockets.
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