Need help on identifying big BLDC motor from 5.25 HDD (hallsensors?)
I have a very nice 5.25 HDD spindle motor with (obviosly) built-in hallsensors (or probably other kind of sensors?). I tried already to find a datasheet, but no success. The 3 spindle coil connectors are easy to identify, but I have real trouble to find out how to connect the hall sensors that are built in. I tried already to put 5 V DC from my arduino to the red/black connectors, then measured several combinations on the remaining 6 connectors which I believe are the hall-sensors. But the signals coming back is not 0 or 5V like a hallsensor should do. I measure slight voltages going up and down when turning the spindle by hand, for some combinations the current is alternating between -200 mV and +200mV. It looks more like a sinuswave for me, but not from the spindle coils. It delivers only a signal when I connect 5V to the red/black connectors.
Unfortunately I can't open the spindle, dont want do damage it. The original driving circuit is missing, only housing, platters and spindle is left. Can anybody help to identify or how to find out about the sensors (6 pins + 1 black + 1 red). I also added 10k pull-up resistors, but no on/off effect when turning the spindle. The HDD is a FUJITSU M2266SA, the spindle is manufactured by Matsushita but google does not return anything useful on the part number(s) DIL-58B 3 or B90L-1415-0021A.
Any help to get this baby running is highly appreciated!