Auto Power-On for the LinkStation Pro

One glaring defect in the LinkStation Pro, at least in my view, is that removing and restoring power (as would happen during a power failure) doesn't power on (i.e., reboot) the device. Someone has to press the power button manually to get the device to start. For a device that's going to act, among other things, as the gateway for remote access, this is unacceptable -- I needed something that could recover unatttended from a power failure.

I'll admit that I first tried a restart crcuit of my own design, based on the ubiquitous 555 timer chip. (This worked great for a restart circuit for a standard ATX power supply, described here.) The trouble for the LS-Pro is that the 555 timer works reliably only with a +5v supply, and the LS-Pro has only 3.3v available.

I found this article, which discusses an auto power-on circuit for the LinkStation Pro. It has this accompanying fuzzy picture of the LS-Pro motherboard showing connection points, and this schematic of the auto power-on circuit.

Here's my own rendering of the auto power-on circuit, which I found helpful when actually doing the construction as it more closely matches the geometry of the parts.


The original poster said he built the circuit without a circuit board, covered it in candle wax, and encased it within the case of the LS-Pro. My assessment is that the circuit board is more or less necessary to avoid excessive risk of shorts, and because it's difficult to obtain adequate mechanical connection soldering wire leads from the discrete components directly to contacts on the DIP package. Also, the interior of the case is warm enough that I'd worry about the wax softening if not actually melting. So while I would have liked to hide the restart circuit inside the device, compromising its reliability in this way would have defeated the purpose of the project.


Here's another view of the restart circuit, resting atop the LinkStation Pro itself.