Power Supply Tolerances

**nasa** · 05-12-2007, 07:22 PM

Hi,

I am troubleshooting a random rebooting problem I am having (yes, I have a lot of luck -- all bad).

One item I am paying attention too is power. I have the following case

http://store.mp3car.com/OPUS_Mini_IT..._p/enc-003.htm

Which has an Opus 120 DC-DC power converter. Monitoring it with speedfan, most everything is within 5%. The only exception is the -12V line which is reporting a consistent -14.4V. I had read *somewhere* that the - lines didn't need to be as tight as the +, but would this much varience cause me a problem?

Nasa

**2k1Toaster** · 05-12-2007, 07:56 PM

That seems like quite a bit of deviation from -12v. The most I have seen from any power supply (desktop or dc-dc). But you are correct that they dont need to be as regulated as the + lines, because they are not used as often in the system.

And the problem you say is random. Is it really really completely random, or can you find a correlation between if or how fast you are moving, the type of road you are on such as bumpy and potholes to smooth, to if it happens on onramps when accelerating or when braking fast, or when it is cold/warm/humid outside, anything like that? Or is it really just random?

**nasa** · 05-12-2007, 08:17 PM

2k1Toaster,

Thanks for the reply. As best I can tell -- it's seems random. I have had the computer reboot 4 times a 20 minute span. On the same road going to the same location doing about the same speed -- no reboots at all. I get the reboots when running on my bench, although it seems to take a longer when on the bench. I have gone in and ensured all the cables were solidly connected, ensured the memory was properly seated, checked temp ranges, etc, etc.

It would really be helpful if I could see a pattern, but one hasn't shown up yet...

Nasa