02-19-2021, 12:10 AM
(02-18-2021, 08:14 PM)TRS-80 Wrote:(01-09-2021, 08:16 PM)kuleszdl Wrote: Regarding the mounting of the RP64 board to the ITXATX case: Why not make an adapter plate (metal or 3d printed), screw the RP64 to that and then screw the adapter plate to the case?
For that matter, why not just use regular standoffs and if necessary, drill another tiny hole or two wherever needed?
I have acquired an entire boxed assortment of them (in different lengths, and including nuts, washers, etc.) off AliExpress for only a few dollars.
I'm not super experienced with case mounting, so I haven't done much research in this area (mostly for lack of knowing what to look for).
Quote:BTW, I am not sure 5A in your case is "plenty" as I think the ROCKPro64 can use up to 3A by itself, then you have the drives in addition to that. Well, that is the size power adapter they sell for it, anyway (3A I mean). I am actually curious what real expected usage is, as that would actually help all of us in planning.
The power supply I'm referring to is this one from Pine, sold as a counterpart to the 3A for heavier power loads, like attaching HDDs. As I stated, our SSDs (Crucial BX500 2TB) are labeled "5V 1.7A", meaning all of them together can theoretically pull 34W, leaving 26W for the rest of the board (assuming a spherical cow maximum efficiency). However, it's unlikely that they will ever pull anything close to 8.5W apiece, more likely living in the sub-watt range being idle most of the time (given NAS usage patterns, i.e. rarely accessed for backup/restore). (This is extrapolated from typical SSD power usage, though, as Crucial's datasheet does not include power consumption statistics. Admittedly, this was not the most thought-out purchase.)
Keep in mind that the "12V 3A" is not just for the board alone, but all peripherals as well. The RK3399 SoC only pulls 6~7W under typical load (according to some TDP numbers out there), with a smattering of draw from other components. People like to attach one or two USB drives to this kind of board, and expect them to work. PCIe devices factor in as well, especially since you might mount an M.2 drive there, or attempt something ridiculous. With those things accounted for, the typical power consumption picture starts to become clearer (for instance, my SATA controller chip is specced to consume a negligible 1W.) However, I haven't measured the board's draw at the wall or looked into its power consumption characteristics, so this is the fidelity of info I can offer.
Quote:Anyway, turns out in the range I am looking (~9A I figure) these power supplies start to come in 4 pin DIN configuration (at least my preferred Mean Well do) instead of the standard barrel like what was on the Cubietrick (and what is on the ROCKPro64 itself). I was looking at GST120A Series (GST120A-12 more specifically, which provides 8.5A @ 12V). Although they have a lot of other models available, too, if you think your power requirements are less. In fact I already scored 3 of them used off eBay for 60 USD total, shipped (only 20 USD / ea!).But there are many more and seem to be common and therefore reasonably priced and readily available.
Anyway, so then I ordered some DIN panel mount female plug, for the outside of whatever case I end up using. I plan then to just solder some (appropriately sized) wires between that plug and into a barrel jack for the board itself, and also into one of the adapters they sell in the store which takes 12V in and puts out the 12V + 5V in a SATA power plug which each drive will need. Tidying it all up with shrink wrap, etc. of course.
You might want to note that the 4-pin connector on the RP64 used by Pine's SATA power cable is directly connected to the same line used by the barrel jack, meaning the board can be powered from it as well (taking care to only sink to one of the two power connectors at a time). This is how some people hook up ATX supplies to the board, IIRC. The connector is JST's XH-series (2.5mm pitch), and you could run connectors from some manner of modular power supply to individually power the board and drives (for the sake of flexibility) if you see fit to go beyond 60W.
