Opening up an RD54 Diskt

Ah, so you did finally get it open :-) I found the fact that the hidden screws took a larger Torx driver ot be particualry evil. A XT8 will fit, and will seem to engage, but it'll strip the heads, making them even harder to remove. I don't know how similar the XT1140 and XT2190 are, but on the old XT1140 I've hard apart, there ar 3 flexiprints from the HDA to the logic PCB. The wide one is almost certainly th head signals, the other 2 are probably the spindel motoe and the positioner (and lock solenoid). What I would do next, since you have an open HDA and nothign to lose on that drive is to trace (using an low-resistnace ohmmeter the positioner coil and lock solaiod conenctiosb back to the plugs that connct to the logic PCB. Then you vcan look at those signasl on an unopenend drive to see if the heads should be moving. -tony