• Power Supply Building

    Ryan Walmsley • 05/02/2020 at 16:09 • 0 comments

    As I found in the previous post that I could not use the small PSU I had because of it missing the negative 12v rail and while I could possibly modify it if I reallly wanted it wasn't worth it.

    However as I originally ordered the Pico PSU for the car I had that arrive so started to set that up.

    I originally tested it with the buck module on my bench power supply and after looking through my parts bin found a 19V 4.22A laptop power supply which is roughly 80W.  

    Just enough for this build as while it can draw more than 80W with some rough measurements on my bench PSU this was only with Prime 95 in essentially a "power virus" mode.

    But under more realistic tests I found that it didn't draw much more than 60w which is excellent.

    I first then tested with it all out of the case and found it ran fine

    So I then started to neaten it up by trimming the length of wire from the PSU to a much more reasonable amount and wired this into the buck module.

    Next was the mains AC cable, the original xbox used a Figure of 8 connector for power and by luck this PSU also used the figure of 8 cable. So what i decided to do was wire a short figure of 8 cable from the original connector to a figure of 8 wire to plug into the PSU.

    To begin I cut the cable off the sacraficed figure of 8 cable and soldered it to the 2 pins. polarity to a certain extent doesn't matter here as this cable can be plugged in either way.

    To make it safe I then applied as much heatshrink as I could and then sprayed it with conformal coating which is used to provide electrical insulation however with just my multimeter on continuity mode I was able to test that there wasn't enough of an insulation layer.

    Because of this I then "potted" the pins, because I have a resin 3D printer I just dabbed some of the resin on carefully and cured it under my UV light. I done this in very small amounts each time building a little layer ontop of eachother and after curing for around an extra hour had this.

    And success it didn't show as being conductive with my multimeter!

    Finally to finish up I wanted to properly test it with my PAT Tester. This can test to make sure there's no shorts between the two pins at 500V and that 500V isn't conducting through the resin. And it seemed to pass perfectly fine!

    Above is pictured then testing it as a whole to ensure there's no leakage from the AC to DC side either and this passed.

    I then superglued the figure of 8 cable in the case and this section was complete.

  • Motherboard Diagnosis - what caused the issues?

    Ryan Walmsley • 04/26/2020 at 10:11 • 0 comments

    So, as mentioned in the previous post I installed the system on another motherboard I had while the one I wanted to use I had to send back because of there being no output from the iGPU.

    I had tried two different CPUs, RAM, all 3 display outputs with no success. The rest was working fine as a discrete GPU worked. I also know all the CPUs worked from where I was installing and testing it fine .

    I sent the motherboard away for RMA and they got it and showed it working fine. What the heck? So I arranged for it back and it didn't work still.

    But when I tried the new Pico PSU, I got and it started working. But the other power supply worked with the other motherboard so what's going on?

    I then tested 2 other power supplies with success and the original didn't work again and furthered on with investigation.

    So what caused it?

    The most likely explanation I have right now is that it turns out the power supply I was using has no -12v rail. Now there's no reason I know of that causes the iGPU to not work without a -12v rail. 

    The negative 12v rail is more a legacy thing from where some ISA cards used them and it was sometimes used to either generate +24v for some devices or the negative rail for Serial (altough even this is rare as some ICs that did the logic conversion have a built in negative rail generators).

    All I can think is that whatever circuit this motherboard has, somehow uses the -12v rail I suspect just enough to activate whatever circuit its using and doesn't even draw a lot of power. 

    However for now as I'm using a pico psu then this isn't a major issue now. But was an interesting issue.

  • Installing the system

    Ryan Walmsley • 04/25/2020 at 18:42 • 0 comments

    One of the first things I did was install the system and some games to test it out and get an idea on performance.

    However at the beginning of this project I actually had to send the motherboard away for RMA believing there was an issue with the iGPU connection on it (which we'll send off in the next one). 

    But for now I had another motherboard of the same socket I could use so got installing.

    My original plan was to install Ubuntu to have as the OS, while most of the games I want to run are native to WIndows the ability to play Windows games on Linux has greatly improved.

    So I put together the rough system,

    Installed Ubuntu Budgie

    And then gave it a try. I installed steam with a few games to try out but...

    Unfortunately it did run too slow. I suspect that while Proton is very good with some games and newer hardware that instead the iGPU isn't the best optimised for gaming under Linux.

    So next I installed Windows 10, I had a spare license key and the install went smoothly. 

    And the games did seem to run much smoother. I do suspect that the better drivers helped but as well proton I believe converts the Direct X calls to OpenGL which isn't as optimal as just running on Direct X.

  • The Plan

    Ryan Walmsley • 04/25/2020 at 18:28 • 0 comments

    So recently I've been getting into playing some console games of which I had some of the games on console.

    While I have a gaming PC there's something nice about playing casual games easily on the TV.
    I started playing one on my XBOX 360 and noticed one thing that was really bugging me, it's really noisy! I mean the noise from this was extremely loud. I found out (as I rarely ever use my 360) this noise was actually not just the fan inside the console to blame but there's also a fan in the power supply.

    As I was wanting to do a Mini ITX build anyway (originally planning to be a computer to have in the car) I wanted to build a small system to play games on instead.

    At the same time I found an old spares and repairs original XBOX  which seemed to be the ideal size.

    So the goal:

    To create a small "gaming" pc capable of playing some basic console games at 720p (which is upscaled on the pc to 1080p) and of similar quality to an XBOX 360 / PS3.