Power switchability of SSDs

Tue, 2017-10-03 12:03 by Sebastian42 · Forum/category:

I'm very confused about the phenomenon of power switching to HHDs. I present below the symptoms in three PCs in the hope someone can make sense of it for me.

Because I switch between hard drives a lot, I ordered from Ebay, and received (eventually), the cheaper version of a 4-unit SATA-power switch - in the form of a metal strip with 4 switches-&-LEDs embedded that fits into the back of the PC, as though it is attached to a PCI card. I found that it is a wonderful item in concept, with the great convenience of avoiding the need to change leads on HDDs when wanting to access different HDDs. Please do not ask me why, I just do, and want that to work smoothly. However after several weeks, one after another (I bought replacements after the first failure) would fail, and all 4 LEDs would light-up, independent of the switch setting. I have since bought one, double the price, with floppy-disc-drive form-factor, which has so far behaved as expected.

PC1 - Four spinning-disk HDDs - the 'strip' switch works fine.

PC2 - Three SSDs and one spinning-disk HDD

PC3 - Three spinning-disk HDDs and one SSD

PC2 & PC3 - The strip-switch LEDs light up 'randomly'.
PC2 - The double-the-price floppy-disc-form-factor switch has not yet failed, but only one week has passed.
PC3 - Having figured that the mixture of SSDs and spining-disk HDDs on the same strip-switch spells trouble, I connected the strip-switch to only spinning-disk HDDs and so far it has behaved well. To be able to isolate the SSD, I fitted a molex-power switch between the SSD and the PSU, with (obviously) a molex-to-SATA power adapter to the SSD. The SSD ignored the On/Off setting of the molex-power-switch, and so the PC booted from the SSD irrespective of the molex-power-switch setting. I have tested the switch unit of the molex-power-switch with a digital multimeter which showed low resistance when closed and hign resistance when open, so the switch WORKS.