Thread: Need help with PSU M1-ATX, there is an intermittent problem

Originally Posted by malkalm

I have been using my car computer for 3 weeks so far. I had this problem at least 3-4 times. When I turn my computer on It doesn't beep and the power led comes on, I can here the HD spin and every thing sounds normal, but no VGA. When it beeps during post every thing works fine. At 1st i thought it had to do with a low charge on the car battery (because i ran the computer for a hour with the car off) , but that shouldn't be problem when the car is on. The last 2 times it happend. I didn't run the computer with the car off. So the car battery should of had a full charge. Does anyone have an idea whats going on.

I have the same issue with a Carnetix 1260 and EPIA M10000

I've been using 90W M1-ATX power supplies and have on occasion had them simply power down (hard off) inexplicably (thermal?). One thing that's a bit scary is that they can pull a very large current when first connected to the car's 12V supply, with or without the ACC line having power.

I've blown 2 10A fuses just by connecting them to the battery for the first time. It may have even been the cause of a fried motherboard. In the future I'll be trying 120W Opus power supplies as others seem to be having fewer problems with them.

Just from the way they behave, I'm guessing it may have something to do with their caps charging but I haven't looked into it.

Thanks for the info, I am going to look into the 120 watt opus PSU.

I have the same issue. Mine posts only once every 10 or 15 starts. The rest of the time it is as you described. If it does not post and I push the reset button 4 or 5 times very rapidly, then it starts fine.

I'm glad it wasn't just me Once I have one of these installed I'm a bit scared to remove it for fear it will fry something. Once they're installed and stay connected they seem to be okay. It's too bad too because they fit perfectly in my design

I contacted mini-box.com and they thought it was a timing issue between how fast the 3.3 and 5V rails come up and when the mobo detects it and suggested I add a 10nF (.01 uF) capacitor on top of C35, which is the 3.3V soft start. I did that but it did not help. My subsequent e-mails went unanswered.

We need to find a fix for this problem

I'm truly happy I swapped my M1 with opus 150.. on the paper M1 is a good product but in the end I see lots of them fried or acting strangely

I see the common factor between us is the Via board and not M1-ATX. For example urinemachine has a Carnetix 1260. So it is possible that something in the board deos not sync with the power supply start signal. But since not all Via boards have the same issue it must be something else that is also playing a role. And since replacing the M1 or Carnetix with Opus solves the problem (or does it?) I think we need to look for something else besides the via board that is also common between our setups....how power gets to it....how it is grounded....wire sizes...power demand from individual rails....etc...