![1999 vs 2009 [4032x3024 - 2MB]](https://pic8.co/sh/w8aboz.jpg){kind=link}
That's a bed-of-nails test point.
Nope. It's a board-to-drive interconnect. Notice there are no connectors anywhere on the board to interface with the drive body for the heads, motor or voice coil. That staggered pad arrangement on the board matches up with a springy connector on the drive body which connects to the drive internals. There is a connector at the very top part of the board with four springy tabs that would mate with a PCB contact pad similar to the large 20 pin one which would be on the drive body. That small 4-pin connector is likely the coil drive connections for the three phase BLDC spindle motor. The board is mounted component side down on the drive so there are no connections on the other side of the board. By contrast, the older board has pin headers for making connection to the drive body but also has some springy contacts for the spindle motor coils.
You are right on that one. I had another drive with the same thing that was covered by foam, but that one was not. Just looked at the drive body...or what was left of it, anyway.
I've had at least one drive fail that worked when I cleaned those pads. I often take the PCB off drives and those pads tarnish something awful. I'm guessing they're silver-plated (the tarnish coloration looks like silver does) and usually the pogo pins on mechanism make a gas-tight weld. I take an eraser and clean them all shiny and wipe the pogo pins before I reassemble, for good measure.
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