L O S T C I R C U I T S

Jumpers and Dip Switches

The A7A266 is essentially jumperless. That is, there are a few jumpers to enable / disable jumper-free mode, and the manual configuration of the voltage ID setting through the soft BIOS (enabled by default). Another jumper directly to the right of the AGP Pro slot is undocumented. In typical ASUS manner, the Clear CMOS jumper is missing, if needed, the solder points can be shorted by used of a screw driver. With most previous ASUS boards, there was hardly any need to use this procedure or, alternatively, to remove the battery since, upon boot failure, the board reset itself to fail-safe default settings. In the case of the A7A266, the failsafe default only worked in a few instances, making it necessary to force the BIOS reset the hard way on several occasions. One example where the BIOS failed to reset itself was when the CPU speed was set to 133 MHz without increasing the memory latencies, resulting in a boot failure.

Closeup of the FSB dip switch located underneath the BIOS and adjacent to the ASUS ASIC. The dip switch for changing the multiplier is missing, the solder points are there, however, thus, it should be relatively easy to reconfigure the board. Connectors What the A7A266 lacks in jumpers, it makes up for with respect to connectors. SMBus, WOL, WOR, additional USB headers and thermal sensor input are standard. In addition, an extra header for the proprietary ASUS iPanel allows hook-up of this nifty device, featuring hardware monitoring and front I/O ports. If no iPanel is used, infrared transmitters can be connected to the same panel. Another specialty is the ASUS AAPANEL next to the Audio / gameport in the standard PC99 compliant backpanel I/O connector block that can be used to hook up the Audio cable from the iPanel if such device is present.

Quality

The A7A looks good, there is no doubt that most components are high quality. Examples are the Nichicon capacitors otherwise found primarily on Intel's house brand. With regard to the power supply circuitry, I am somewhat at a loss since the controller chip only has a number code without reference to the manufacturer. A total of four MOSFETs around the CPU socket suggest that a dual phase design is used but without part numbers or reference diagram it is impossible to make a conclusive statement. The ICS 94235 AF system clock generator is programmable in 1 MHz increments from 100 MHz up to 166 MHz. Interestingly, there is a second clock generator in the upper right corner of the PCB (ICS 93705; no data sheet available yet but the 93xxx series is usually used for DDR clock input). The AS-009 A0 logic chips between the SDRAM and the DDR slots appeared to be from different manufacturing batches since the marking layout varied from one chip to another. All in all, there are very good components being used on the A7A266 and others that appear to be no-name or else ASUS house brand ICs, which is not necessarily negative.

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