youe Posted December 15, 2020 Share Posted December 15, 2020 (edited) I've been using a Helios4 for nearly 2 years now and it's been fantastic. A couple days ago, it stopped working though. The serial console revealed a boot loop at "U-Boot SPL" and only showing the disks, but never attempting to boot the OS. I did some forum searching and discovered the PSU could be the issue. Using a multimeter, I tested the PSU pins and I get the following (see diagram): PIN 1: +2.66V (fluctuates between 2.64-2.66) PIN 2: +2.66V (fluctuates between 2.64-2.66) PIN 3: GND PIN 4: GND What are the voltages that Helios4 expects for these pins? Should both 1 & 2 be 12V or should one be 12V and the other 5V? I already ordered the following PSU as per another thread (however, this won't arrive for another week) https://www.amazon.com/gp/product/B07NCG1P8X/ Edited December 15, 2020 by youe 1 Link to comment Share on other sites More sharing options...
youe Posted December 16, 2020 Author Share Posted December 16, 2020 Since I had collected as much information from the broken AC adapter brick as possible, I decided to cut off the connector. This revealed only 2 wires which meant there is only one possible configuration. Both pins 1 and 2 must be 12V. I grabbed one of my old computer power supplies, and fashioned a terminal connector to tie the 2 wires to the 12V rail and ground. I verified the 4 pins on the connector, plugged it in and my Helios4 booted up without any issues. I'm still waiting about a week and I'll swap out my 500W temporary PSU when it arrives. For anyone with similar power issues, hopefully this thread may be helpful to them. Here's the appropriate pinouts of the 4-pin AC adapter required for Helios 4 (see previous diagram for pin locations): PIN 1: +12 PIN 2: +12 PIN 3: GND PIN 4: GND 3 Link to comment Share on other sites More sharing options...
gprovost Posted December 18, 2020 Share Posted December 18, 2020 You are correct, the Helios4 PSU is outputting DC 12V / 8A. PIN 1: 12 VDC PIN 2: 12 VDC PIN 3: GND PIN 4: GND And yes between the 4-pin connector and the AC/DC power adapter it's just 2 wire ( +12VDC (red) and GND (black) ). So it should be easy to replace the power block with another while keeping the 4-pin connector as you did ;-) Link to comment Share on other sites More sharing options...
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