One lot of JB-199 (approximately in between SN 100015 - 110395) that has Ashrock G41 mainboard can show under exteme heat the symptoms of intermitten interuption of power supply.  The JB-199 unit will power off suddenly and then power on, sometimes repeatly, without going fully into Windows or to JB-199 program.

This problem is due to the power cable extension that is used inbetween the power supply cable coming from the power supply and the main board.  Please refer to the attached 3 pictures.

Picture 1: Shows power supply cable with extension that is connected to the main board.

Picture 2: Shows the extension removed from the power supply cable and the main board.

Picture 3: Shows the power supply cable directly connected to the main board without the extension.

As shown in the picture, the extension needs to be removed.  The problem comes from a bad connection between the power supply cable and extention.  This bad connection is occuing only in extremely hot environment inside the JB-199 unit.

The extension has a cable with 2 wires going out to the Rear board.  Now that the extension is removed, this cable to the Rear board must also be removed.  The purpose of this 2 wire cable is to supply the power to the Rear board before the main board thus eliminating the poping sound at the start of JB-199.  This popping sound does not damage the unit and only happens at the start of the unit, something that is far less inconvenient than the power supply interruptions. 

Attached files:

• AsRock & Power Extension Cable.zip