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Thanks for having a look at my question.

I know this may seem like an odd question but here is the history of it.

I have a Solidoodle 4 3D printer, Its powered by a knock off xbox 360 brick adapter modded from the factory with a standard looking round power plug. (similar to what you will find on any wall wart) Round with the hole in the middle.

I got a roof leak in my garage and the power adapter that came with my 3d printer got soaked and currently is no good. Tried to buy a new one from Solidoodle but they are now out of business.

The original adapter was 12 volt 12.5A output, I found a used Xbox one power adapter and its rated for 12 volt 17.9A. the printer is pretty flexible on its power supply needs but more amps is better.

Question - I have the dc end of the power cord moved into the xbox one adapter in the appropriate terminals, (12V and GND2) all is good so far, however my measured voltage is only 143.4 mv when plugged in.

There are 3 other terminals on the adapter , +5VUSB - obviously the 5 volt rail, the last 2 are marked PS_ON1 which I am assuming is the power switch on the Xbox and the last is RSENSE which I have no clue what that's about.

I am assuming to have the Xbox 1 adapter turn on I need to put PS_ON1 either to ground, +5V or to RSENSE can anyone help me out with the wiring schematics for this adapter? I have no issues leaving the power adapter on all the time, when its not in use I usually turn off the power bar its plugged into anyway.

update:
The connector appears to be wired straight, cannot identity any resistors or the like in the connector:
connector internal

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  • \$\begingroup\$ The Xbox One has a 4 conductor plug. Where are you seeing R-Sense? Did you open the PSU up? \$\endgroup\$ – Passerby Apr 11 '16 at 6:08
  • \$\begingroup\$ Hi Passerby, Yes I have the PSU open, changing the output wire to a standard 2 wire DC output, \$\endgroup\$ – Jason Harding Apr 12 '16 at 2:17
  • \$\begingroup\$ I believe in the connector the rsense wire is the grey one, honestly the connector did not come apart nicely no I could have shorted it, but from the grey wire to the yellow line, which is 12v positive shows open, to the black line 12v neg is shows 0 ohm, dead short \$\endgroup\$ – Jason Harding Apr 14 '16 at 4:08
  • \$\begingroup\$ Checking rsense on the board to 12positive also on the board shows 30.6 K ohm \$\endgroup\$ – Jason Harding Apr 14 '16 at 4:08
  • \$\begingroup\$ I just connected a small 12 volt, 0.09 A fan to the output connector on the PSU, Measuring the voltage it was at 14.04V with no load, Adding the fan drops it too 14.01. a very small change however its contestant whenever the fan is connected or disconnected. \$\endgroup\$ – Jason Harding Apr 14 '16 at 4:12
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Typically for Xbox related power supplies, you need to tie PS_ON to the 5V standby rail. You could do directly, but I would use a 1kΩ resistor just in case.

R-Sense normally indicates a Remote Sensing option for a power regulator. It would normally be connected at the far end of the power supply's connector, to compensate for any voltage droop from the cable. Considering this supply can pump 17 Amps down these cables, it can lead to a not-insignificant voltage droop. The internal regulator would then adjust the output voltage at the PCB so that it senses the voltage at the far end to be 12 Volts. Logic dictates it should be connected to the 12V input on your 3D printer's input. Use a multimeter to test the old connector for continuity on the R-Sense wire to 12V. You may need to cut the old connector open to make sure there is no diode or resistor needed there.

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  • \$\begingroup\$ Hi passerby, Thank you very much for the very informative answer, It explains both the RSENSE and the "how to turn the darn thing on" I am Just digging around in my scrap pile to see if I can find a Black, Brown, Orange, Tan, Thanks again for the help \$\endgroup\$ – Jason Harding Apr 12 '16 at 2:22
  • \$\begingroup\$ @JasonHarding the resistance value isn't crucial, I'd just use anything in the 1k~10k range as a "just in case" precaution. Most modders just connect it directly from what I see online. \$\endgroup\$ – Passerby Apr 12 '16 at 2:24
  • \$\begingroup\$ Hi Passerby, Not sure if you may be able to give an additional suggestion on this one or not, I have my 1Kohm resister in place and the power supply fires up not a problem, fan kicks on and I am getting voltage at the output, however the voltage is reading 14.05V, not the 12 V I was expecting. I know the 3d printers are pretty forgiving but not sure if that may be pushing it. Is there way to reduce the output voltage to closer to 12? \$\endgroup\$ – Jason Harding Apr 14 '16 at 2:52
  • \$\begingroup\$ That's what the R-Sense does. Did you take the old connector apart to see how it was wired? And sometimes even a regulated supply like that has a minimum load for proper regulation. Try putting a 12v fan, like from a pc on it, then measuring it @JasonHarding. \$\endgroup\$ – Passerby Apr 14 '16 at 2:58
  • \$\begingroup\$ @JasonHarding so if r sense is connected directly to the connectors 12V pin, and measured that there is no resistance between the two wires, you could so the same on your connector. \$\endgroup\$ – Passerby Apr 14 '16 at 3:33

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