PC-Chips M571 undocumented voltage settings (V7.0A) - Part 1 ------------------------------------------------------------ The following results are theoretical calculations based on the published specs of the various devices and on the values observed on the various resistors. I made no actual voltage measurements since doing so requires a proper load. Also note that the m/b designers have apparently allowed for a voltage drop of 70mV between the regulator output and the CPU socket. Hence the "V at CPU" figure is the one you should be trying to set. Some instructions call for a certain resistor at a certain jumper location. In these cases remove all voltage jumpers and install a "resistive jumper" on the relevant pins as shown. The gold connector pins can be obtained by breaking apart an ordinary two-pin PCB jumper (or by melting away the plastic with a soldering iron?). The bridging link can be cut and trimmed with sidecutters. Alternatively, use a Reset or LED connector from an old PC case. voltage gold pins header || || __________ O O O O O<>==<>---|resistor|----| cover resistor and JP6 | |--------| | <--- pins with heatshrink O O O O O<>==<>-----------------| tubing V at CPU V at regulator What to do ----------------------------------------------------------------- 2.19 2.26 all jumpers out 2.29 2.36 120K resistor at 2V8 jumper location 2.40 2.47 47K resistor at 2V8 jumper location 2.51 2.58 22K resistor at 2V8 jumper location 2.60 2.67 12K resistor at 2V8 jumper location 2.69 2.76 4.7K resistor at 2V8 jumper location 2.79 2.86 install 2V8 jumper 2.90 2.97 install 2V9 jumper 2.99 3.06 3.9K resistor at 3V2 jumper location 3.09 3.16 1.8K resistor at 3V2 jumper location 3.20 3.27 install 3V2 jumper 3.30 3.37 install 3V3 jumper 3.40 3.47 1K resistor at 3V5 jumper location 3.51 3.58 install 3V5 jumper 3.58 3.65 install 2V9 & 3V3 jumpers 3.69 3.76 install 2V8, 2V9, 3V2 jumpers 3.84 3.91 install 3V5 & 3V2 jumpers 3.88 3.95 install 3V5 & 3V3 jumpers 4.00 4.07 install 3V5, 3V3, 2V9 jumpers More accurate voltage selections are possible by fine tuning the resistor values. Also a better approximation for the 3.8V setting can be achieved using a combination of one jumper and one resistor. If anyone needs this to be recalculated, please let me know.