M2-ATX 6-24V Intelligent Automotive ATX Power Supply Installation Guide
Please take a moment and read this manual before you install the M2-ATX in your vehicle. Often times, rushing into installing the unit can result in serious damage to your M2-ATX board, computer and probably your car’s electrical system. The M2-ATX board has several wires that need to be installed in various places. When installing, always double check the polarity of your wires with a voltmeter. Avoid using the cigarette plug as a power source, often times the contacts are not capable of delivering high current to your PC.
Thank you for purchasing the M2-ATX power sequencer / vehicle ATX power supply. The M2-ATX was designed to work with a wide variety of main boards such as the VIA mini-ITX motherboards as well as Pentium-M Celeron or full power P4 systems.
Power challenges in a Vehicle PC
The 5V Standby Problem: One of most difficult tasks of operating a PC in a vehicle is power consumption while the computer is OFF. Even when your computer is OFF, it will still consume about 100mA on the 5V rail. All power supplies provide 5VSB (5V standby) so that the motherboard can issue at least a PSON signal. When the computer is in the suspend mode, it will consume even more power, because the RAM needs to be powered at all times. No matter how big your battery is, it will eventually drain your battery in a matter of days.
The M2-ATX is addressing these issues by cutting off the 5VSB rail after a pre-defined amount of time (see jumper chart, HARDOFF). When 5VSB is always active (HARDOFF=Never), M2-ATX constantly monitors the battery levels. When battery level drops below 11V for more than one minute, M2-ATX will shut down and re-activate only when the input voltage is > 11V.
Engine Cranks, under-voltage and over-voltage situations. Another difficult task is maintaining stable 3.3V, 5V, 12V and -12V power to your PC. While car batteries are rated at 12V, they actually provide voltages in between 7-11V (engine cranks) or as high as 80 volts (load dump). Most of the times, your battery will stay at 13.5V (while car is running) but extra precautions need to take place in order to prevent such situations. M2-ATX can operate as low as 6V and as high as 28V while providing strict regulation on all rails along with input voltage clamping and reverse protection.
Loud amplifier pops when PC starts. If your PC is connected to your car amplifier, you will hear a loud pop when the computer is first started. The M2-ATX has an ‘anti-thump’ control that will keep your amp OFF while the PC starts. Simply connect J6 to your amplifier remote control pins to activate the ‘anti-thump’ feature.
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