Tror jeg har fundet ud af det..
The MSnS-E modification for the 7-pin HEI is a simple and effective improvement for many set-ups. It requires changing two jumpers, and changing one resistor. This circuit supplies 5 Volts to the input circuit (and optoisolator LED) and uses the ignition module (such as the 7 or 8 pin HEI module) to ground the LED. The LED is guaranteed to receive 5 Volts this way, and the module is only required to sink the LED current (~4 milliamps). This results in more reliable triggering for many people. On a V3 main board:
Remove the jumper to OPTIO IN, and jumper OPTO IN with a wire to one of the +5V vias in the proto area,
Remove the XG1 to XG2 jumper, and jumper XG1 to TACH SELECT (do not jumper XG2 to anything),
Replace R12 (390 Ohms) with a 1K Ohm to 2K Ohm resistor (1/4W).
rigtig?
-Amby