Building a quiet MythTV box – selecting a case

April 20, 2012

I’ve started looking around for a quiet but thermally good case for a MythTV box. My first thought was to do an HTPC case – the Lian Li HTPC C60 looked good.

But then I started worrying about airflow around the case. I’ve got a fairly narrow spot to put it in – about 46 cm – so a PC that’s 44 cm wide doesn’t leave a lot of room for cooling.

I decided to look into mini towers instead. The Lian Li V600F looks like it would be nice, but it has these ugly blue fans.

I also looked into the NZXT H2 (some were saying it was too flimsy), Antec P183 (too tall, not a mini tower) and Silverstone TJ-8e (an 18 inch fan in front, but only that. How hard to get a replacement when it dies?)

Now I’m leaning towards the Lian Li B10. It’s too bad that SPCR hasn’t reviewed it – they seem to know a thing or two about quiet and heat.

Airnet AES108P power supply

April 3, 2012

I have recently moved, which means I’ve disconnected all my wall warts and had to reconnect them.

Normally, this isn’t a problem – but for one ethernet switch, it was. The box is labelled “Fast Ethernet Switch” with no other markings on the front.

The back has 8 ethernet jacks (ok so far) and a DC tip connector labelled “AC IN”. Great. The DC connector looked like a standard 5.5 mm outside / 2.1 or 2.5mm inside connector.

Markings on the bottom of the box: ES3108CH3 and AES108P. That appears to mean it was an Airnet AES108P, also known as a Pro-Nets ES3108CH3. Airnet appears to be out of business, and Pro-Nets is a Chinese exporter who lists it as “Power: 1w” (but no voltage).

So I cracked the box. The circuit board had a marking I took to indicate centre positive (which would mean not AC in), so I attached the bench supply and worked my way up from 0.

The device needs slightly more than 5v to turn on. I was getting it booting up at around 5.6 v, drawing about 520 ma with 3 network cables attached. I suspect it came with a non-switching wall wart rated for 5v. I tried with a 6v transformer I had handy, and that was too much. (Incidentally, if it’s nominally 5v, that’s more like 2.5w than 1w.)

I fear I have let the magic smoke out now… I had it running and moving packets at a little higher than 5.5 v, but now it boots up partway and croaks. Sigh.

Perhaps this will be helpful to someone else who’s not sure what to use. Seems like a non-switching 5v 1a transformer would be about right. A 1500ma switching 5v transformer I had did not work.

I’m not taking responsibility if this smokes your switch… or burns down your house. Use this info at your own risk. Let me know in the comments if it worked or didn’t.

Building a quiet MythTV box – step 1 – thinking aloud

April 1, 2012

Due to decreased WAF for the old MythTV box, I’m looking into building a quieter one. I’ve decided to do a couple of things differently:

  • Use HDHomeRun for capture cards. That way, I won’t be stuck to a particular bus architecture. It also means the capture cards won’t be generating heat in the case.
  • Use a pair of 5400 RPM hard drives (maybe a 2.5″ one for the OS, and a 3.5″ one for the recordings? Need to have fans on all of them to cool them down.
  • Replace all the fans with FDB or maglev bearing fans
  • Use an external PSU like the PicoPSU or something like that. Here’s an adapter to make it fit in a standard fan bay. (This might also be a good idea for ham radio PSUs…)
  • Use an HTPC case or at least a quiet PC case
  • Probably end up with an nVidia video card.
  • I think I want a core2 duo 3.1 MHz or so motherboard/ processor combo
  • Does the Pico PSU mean I won’t be able to drive a DVD player? Maybe another external one (eSATA?) Am I going to end up with a bunch of individual set top boxes?

The CPU cooling fans, video card and hard drives should generate most of the heat (and noise). Need to figure out how much power a video card uses.