the power switch on mine doesn’t appear to do anything. no matter the position, when the ATX power supply is connected and plugged into the wall the board is ‘on’. I get the appropriate voltage at each terminal pair. Is that expected, that the switch does not do anything?
Thank you
Arch
Hi Arch,
The On/Off switch on this should work just fine as far as I can tell. It may be a bad switch or hardware connection. Can you take a few photos of the top and bottom of your kit and attach them to your response? That may help us identify the problem.
Pictures are attached. I had trouble with getting good lighting so please let me know if you need them re-done or anything.
Looks like the ground pins on the ATX connector are not soldered. I would check all the solder connections and reflow any that need it.
/mike
Mike is 100% correct here. That switch is a little different than other SPDT circuits where it pulls the Power Supply On pin low when in the off position to turn the supply off. Without any ground pins soldered, it will just be floating. Try soldering the ground pins on that ATX connector and the switch should work as expected.
Let me know if that does not fix the issue or if you have any other questions about this kit and I would be happy to help.
I hadn’t soldered the pins that didn’t appear to be connected to any traces, but after soldering all of them nothing changed. As soon as the ATX power supply is connected the LED illuminates and there is the appropriate voltage at each connector. The switch doesn’t change anything.
At this point, I’ll assume I soldered something incorrectly, but it is not worth my time to try to figure out which one(s) are wrong. I am thrilled that I have an inexpensive benchtop power supply, the fact that the power switch doesn’t turn it off or on doesn’t change that.
Thank you for the help.
Arch
Those pads actually connect to the ground pour using thermal reliefs. You have the round pad and four short thin spokes to the ground pour. This gives you a chance to solder the pin to the pad without having the plane suck all the heat away.
If you can’t turn it off, there’s likely a short between the green wire on the ATX connector and ground.
/mike
If you unplug the ATX power supply from the board does it remain on?
All the switch on the board does is ground the POWER_ON pin on your ATX supply to tell it when to turn on. If the power supply is on when not plugged into the board, the issue is in the power supply.
Try unplugging the ATX connector from the board and connecting an ohm meter between pin 16 and one of the grounds and see if you get continuity only when the switch is in the on position. If you’re seeing continuity all the time, you either have a faulty switch or there’s a short somewhere in your board that grounds pin 16.
Can this kit be used to supply 24V to a 3D printer heated bed by connecting the bed ground to -12V and the bed 24VDC to the +12V pin on the board?
In general, the -12v rail can’t provide much current, so this won’t work.
I realize that this is a very old thread, but I did want to mention that I’ve had at least one ATX power supply “fail” because the “remote power switch” circuit failed inside the power supply, and everything else still worked. (Changing out the power supply solved the problem. In that particular case, having to use the “mechanical” switch was unacceptable, but that may be fine for a bench power supply!)
