BUILD Need you help/opinion on a build/configuration idea

[Stux]

Awesome.

One word of warning. I did a lot of research into this board and this case.

The backplanes are missing power conditioning capacitors and are thus not true hot swap back planes. Because of in rush current, there is a chance of errors occurring on other drives if you hot swap drives in this case. You should power down before swapping/installing drives.

Pity. You can see on the backplanes where the capacitors should've been.

 

[Constantin]

FWIW, the BP2SATA backplane connects one SATA power plug to two drives, the BP3SATA backplane has two SATA power plugs - the lower one connects to one drive, the upper one to two drives.

I'm considering retrofitting the caps in question. I wonder if anyone has a working hots-swap backplane with the relevant caps?

A silverstone SATA power cable I recently spied here was listed to offer 2200uF across 4 drives. That in turn suggests something like a 560uF-25V Nichicon cap for 1-1 connections (one SATA power connector to one drive) vs. 1000uF for the 1-2 connections.

But then, what decoupling caps to use? IIRC, there are two 1206 and two 0805 pads per power rail. Will have to break out dial caliper to confirm. Seems like an opportunity for a 2.2uF ceramic and a 0.1uF ceramic to filter the high-frequency noise.

Would I hot-swap them even with said decoupling? Most likely not. Just there to keep noise on the power rails to a minimum.

 

[Constantin]

OK, for anyone with a desire to retrofit capacitors, here are some preliminary measurements to consider:

• The larger SMD components on the board are 1206-size (3, presumably on 12VDC bus), the smaller ones are 0805's (5 altogether, 4 on what is likely the 5VDC bus, one separate - perhaps 3.3VDC bus?). I plan on fitting 2.2uF X7R ceramics on the 1206 pads and one 1uF, one 0.01uF on the 5VDC bus.
  
• The through-hole components feature leads about 0.13" (3.3mm) apart, with a maximum OD of about 0.37" (9.4mm). Per Digikey, the biggest 25VDC Aluminum Electrolytic that will fit is a 680uF. Only some of the vias for the capacitors are filled with solder.

Considering how many drives are hanging off each PS wire harness, I figure I'll be pretty close to the 2200uF that Silverstone and others seem to use a 4-drive backplane capacitor bank. Shouldn't be too hard though getting SMD components mounted w/o the benefit of a stencil is not as much fun as when one can use one.