HOW TO: Getting your CarPC ready before installing it in your car.
I think how to guides from experienced members will contribute quite a bit to these forums if we can get the right people to put their own experienced information into them.
This how-to came about from the overwhelming amount of M1/M2-ATX power supply "problem" threads. In some cases the M1/M2 was at fault but in lots of other cases the M1 or M2 was prematurely blamed for the problem in the thread title when in fact it was a different problem or error altogether. Now there is a multitude of M1/M2 error threads causing people to think these PSUs are no good or faulty.
Here is what I did to make sure my CarPC worked perfectly before I put it in my car. I could probably add pictures later as I did some extra wiring of switches and wire disconnects.
Because the DC-DC PSUs used in CarPCs do not accept AC voltage that is available in your house then an extra, regular ATX power supply makes testing ALL of your CarPC components very easy. You can use these power supplies to test both the regular PC components as well as your DC-DC car power supply. You won't need a very large ATX PSU to power your CarPC as it is most likely a very lower power PC. I think the 300W PSU I bought was $20 and I didn't directly modify it at all so it could be used as a replacement PSU for a regular desktop PC.
Obviously if you want to get your PC up and running without your DC-DC PSU you can just use your ATX power supply directly connected to the motherboard, hard drive, optical drive and any other internal components as you would with a regular desktop PC. This will let you make sure your PC is in good running order and simplify your initial installation. Once your PC is set up with your OS and front end software you can then get to simulating running your PC in your car.
The next step is to make sure it operates (turns on, hibernates, stand-by, sleep, shuts down) as you want it to when you install it in your car. Make sure the ATX PSU is completely disconnected from your PC and install your DC-DC PSU in its place. Because your DC-DC PSU only accepts a 12V input (like from your car battery) then you need a way to supply 12V with enough amperage (current) to your DC-DC PSU so that it can correctly run your CarPC. Here is where we can utilize your ATX PSU once again.
What I did was take one of these:
http://www.cableuniverse.co.uk/catal...ges/rb-512.gif and cut off the nearly-useless floppy drive power connector and expose the yellow (+12V) and a black (GND) wire.
I use the Ampie case and it utilizes the Molex Mini-Fit Jr http://www.molex.com/cmc_upload/1/07...491/5559dn.giftype of connector on the backplate. To connect to this I purchased the male-type of conenctor http://www.molex.com/cmc_upload/1/07...488/5557dn.gif. Wire your DC-DC psu to the female connector on the ampie case and then wire the yellow and black wire from the splitter cable to the male conenctor making sure the black wires connect together and the yellow wire conencts to the BATTERY wire for the DC-DC PSU.
Now you should be able to connect the power splitter cable to one of the ATX PSU's power leads and then connect the other end to your DC-DC PSU connection.
The final step is to make your ATX PSU turn on without having to be connected to a motherboard. Following this diagram will allow you to control the on/off of your ATX PSU using the switch at the back or by simply unplugging it.
Now that your ATX PSU is able to supply 12V to your DC-DC PSU there are a couple more additions your can make to almost completely simulate your car's environment. I wired switches to the startup/shutdown controller jumpers on my M1-ATX PSU. This allows me to easily change the timing of the shutdown controller as well as enable or disable it completely. Because 3 jumpers are utilized in the 8 timing schemes, I needed 3 switches wired to the jumpers. I then drilled a hole in my motherboard backplate and attached the switches. I also added manual power and reset switches to the backplate as well.
A modification that I may add is a switch for the ignition wire on my M1-ATX. I would wire a momentary switch that would enable 12V from my ATX PSU to be present on the ignition wire of my M1-ATX. This would simulate starting a car.
I also wired the amp turn-on wire from the M1 to the power connector on the ampie case along with additional +12V and +5V wires. The 12V wire was then used to connect to my LCD and the 5V will be used to power a USB hub or any other 5V devices if needed.
If people find this useful and want to add anything I can update this post. If not I will let it sink to the bottom of the forum. Also, if anyone wants pictures of the connections I made and the switches I wired I can add them.