[mythtv-users] EPIA mobo won't boot

[Mike Perkins]

Mike Perkins wrote:
> I have suddenly had a strange problem with my minimyth front-end that I 
> thought I would describe here, in case anyone out there has come across 
> it and can offer a solution.
> 
> I built a minimyth front end last summer, after a box shuffle round 
> meant that the existing front end got reassigned. It uses this motherboard:
> http://www.mini-itx.com/store/?c=2#epialn
> - except that mine is marked LN10000EG, not LN10000G. I don't 
> necessarily think that the model # is particularly relevant to the 
> problem, I might be wrong.
> 
> When I built this box, I installed a PVR-250 card, intending to connect 
> it to my cable box at some later date. The whole shebang ran under 
> minimyth (thanks, Paul Bender :) perfectly for some 6 months with no 
> issues at all.
> 
> (Snipped)
> 
> Now the box won't boot properly. It lasts about 10 seconds from 
> button-push and then quits. My initial investigations show a possible 
> earth loop, 3mV from end of S-video cable to minimyth chassis, but I 
> don't think that's enough to cause problems. I swapped the power supply, 
> same result. I've done the usual close inspection of the motherboard, no 
> blown caps, no obvious brown areas, etc. I can get the thing to boot, if 
> I keep powering it up and letting it keep trying. Eventually it lasts 
> long enough to network boot and it's usually ok after that.
> 
> That lead me to believe that it's not booting because it thinks it's 
> /not warm enough/. If I hit the delete button to get into the BIOS, 
> which works ok, then leave it sitting there for 5 minutes to warm up, it 
> will (usually) boot ok. Once up, it will last for many hours with no 
> problems. Have I managed to screw some temperature sensor on the 
> motherboard? Or is it a related wayward BIOS setting I can fix? Has 
> anyone seen anything like this before?
> 
If you remember this problem, I have now solved it, and I think it's worth 
noting for others who use mini-ITX boards. It seems this board has both a high 
and low internal temperature sensor, and that the low one got set to some random 
not-very-helpful value somewhere along the way. The user can set the high end of 
the range, but not the low end. That's why the system eventually booted up, once 
I'd got the board warm by fiddling with it. Eventually, I used to hit the Del 
key at startup, and leave it on the BIOS menu for 5-15 minutes, but this has 
zero WAF, obviously.

The fix is to clear the CMOS by moving, while the system is unpowered, the 
(unlabeled) clr_cmos header from 1-2 to 2-3, wait a few seconds, then move it 
back. After that, it was necessary to go into the BIOS and choose "load 
optimised defaults", reboot and then change all the BIOS settings I changed 
before. Now the system boots perfectly. Well, as perfectly as it's ever going to.

* Someone mentioned putting the PVR-250 card back. Doesn't seem to make a 
difference, although the point was taken. I'm not very confident of the power 
supply in the case I bought, which is this one (which was cheap):
http://www.mini-itx.com/store/?c=3#media
It has a built in PSU, with a thick bundle of cables coming out of one end which 
interferes with any PCI card one might wish to add in (such as a PVR-250), so I 
had to do some careful pruning. The tiny fan is also noisy, although can't 
really be heard while you're watching something. If I did it again I'd choose a 
different case.

* Did another eyeball of the caps, couldn't see anything.

* I think my "earth loop" idea was a red herring, but I'm going to be extra 
careful with my AV connections in the future in case anything else gets spooked.

-- 

Mike Perkins