Medion PC screen doesn't display anything | Joachim De Zutter
Computer Model: ALDI Medion Desktop PC MT6
Motherboard: Medion MD-8088
Problem description: the screen stays black when the power button is pressed.
The computer doesn't complete the POST, the OS doesn't boot and there's no beep.
The cooling fans of the graphics card and CPU are spinning, the harddisk spins.
The power supply is 350 Watt and the power button and power lights work fine.
The ATI Radeon 9800XXL AGP graphics card was removed and a working MGA Matrox Millenium 2064W-R3 64-bit PCI graphics card was inserted.
The power button was pressed, nothing appeared on the screen.
When both 256 MB DDR PC3200 RAM are removed the POST was not completed and there was no long beep to indicate memory failure. This indicates a system board or power supply problem.
One 256 MB DDR PC3200 RAM was reinserted.
The computer was turned off, the CMOS battery was removed for a while and reinserted, so that the motherboard BIOS settings were restored to the factory defaults.
The power button was pressed and the computer completed the POST (the Intel Pentium 4 logo was displayed on the screen).
The MGA Matrox Millenium 2064W-R3 64-bit PCI graphics card was removed, and the ATI Radeon 9800XXL AGP graphics card was inserted.
The other 256 MB DDR PC3200 RAM was reinserted.

1. The computer is turned off, nothing is changed to the configuration.
2.a) when pressing the power button of the computer within 2 minutes, the computer will complete the POST and display the Intel Pentium 4 logo.
2.b) when pressing the power button after 2 minutes, nothing appears on the screen.
3. When all memory modules were removed and the power button is pressed, the motherboard sometimes gives a long beep. Sometimes it doesn't.
4. When 1 or 2 memory modules are inserted and the power button is pressed and the CMOS battery is present and not dead, the computer completes the POST and displays the Intel Pentium 4 logo.
5. Go to 1

The 3 Volt Lithium CMOS battery is the CR2032 size (20mm diameter, 3.2mm height). The battery wasn't replaced for about 6 years. Replacing the battery with a newly purchased one didn't resolve the problem.

It appears that the motherboard, which is often called an MSI MS-7048 is malfunctioning.

Capacitor plague

On closer inspection, there appears to be one bulging elektrolytic bad capacitor close to the PhoenixBIOS chip.

IEEE Spectrum article: Leaking capacitors muck up motherboards
http://spectrum.ieee.org/computing/hardware/leaking-capacitors-muck-up-motherboards