Saturday, December 8, 2012

ATX PSU Repair

As noted in the HTPC build I used a repaired Ultra D0408 ATX PSU. I was using it in the P4 and it would work fine for a long time, then just start randomly rebooting, then it would be fine again. At first I thought it was the motherboard or ram, but then discovered if i bumped the desk or case it would almost always start acting up. Of course that screams "Something's Loose!".

So I had the opportunity to remove it and inspect it as I did my upgrade. Here's what I found:

Caps all look ok, no bulges, etc.
Cover Off
Be very careful when taking these apart, Voltages may remain for a very long time. I held it by the wires to remove the board, flipped it over and checked those 2 big caps (upper left). They had less than 2VDC in them, but depending on the failure it could be over 300VDC.

Bottom of board
Now we can see something, I don't know if you can see it in the above picture but in the lower right corner there is a capacitor that has come loose from the solder. It is on the 12V rail. The heatsink on the left of the unit also has a bad solder joint, but it appears to be isolated.
Bad solder joint (about in center)
So I soldered it up and will try it out. These units are cheap, so it doesn't pay to spend much time fixing them, but sometimes it's something simple like this. It's also practice for things like the Parrallax. Time will tell if that was the problem or if it's something more serious.

HTPC & Home Server Build Part 1 - Hardware

I moved over the summer and I now get 14 Channels of free over the air TV (up from 3) and yet there's still nothing on. It seems all the good stuff is on when I'm busy (or sleeping). So I've been messing with MythTV on a old P4.

It worked pretty good except for a few drawbacks:
  1. It is kind of noisy.
  2. It's a bigger power hog than I anticipated. It consumes about 100W idle. I figured it out as costing me about $85/yr in electric. Not bad for my TV bill, but a little irritating too.
So I was looking around on black friday and found a nice little mini-ITX motherboard with 8GB of ram included for $65. It's no Phenom X6, but since it will spend a lot of time idle or under light loads I think it's a good fit.

  • Biostar Deluxe A681-350 (AMD E-350 1.6GHZ Dual-Core APU)
  • 8GB of G.Skill Ripjaws X DDR3
  • Hauppauge WinTV HVR 950Q (may swap with a Sabrent TV-DGUSB eventually, but I have to re-compile a kernel module for that)
  • Salvaged 250GB Sata Drive (someday I'll upgrade to a 1-3TB Sata)
  • Salvaged ATX case
  • Repaired Ultra D0408 ATX PSU
  • Total idle power consumption measured at 40W
Biostar A681-350 and G.Skill Ripjaws X DDR3
Motherboard with ram installed
All Assembled
I'm still figuring what all I want it to do, so far I've got:
  • MythTV, that's the big one, the main purpose of the whole project.
  • File and Backup Server
  • Local web server for development, testing, etc.
I will do a series of posts covering the software installation and configuration eventually.

Curiously the my complete setup with the P4 consumed approximately 100W idle and 200W with the screen on. The new one consumes 40W idle and 100W with the screen on. I don't understand it, it's the same screen! Could the video card in the P4 detect the screen was off and power down? Would a video card consume nearly 50W? Is my Kill-A-Watt Broken? Tune in next week...