eMMC/M.2 extender board interference


#1

I just set up the computer and noticed that the M.2 extend adapter plugged into the Rock Pi is pressing on the eMMC die, warping the adapter board. If it were just PCB to PCB contact, I’d be less concerned, but this is silicon to PCB contact and that cannot be good long term for the eMMC die.

Should I be concerned?


#2


#3

Thank you for your using feedback!

We must admit: because of the contact, there is indeed danger.

We have realized the risks of long-term use and adjusted the design.

New design details will be shown here.

Thank you again for your positive feedback. We like this communication too much.


#4

What’s an update on this? Is this mentioned somewhere more official than this thread? If not, could you please?


#5

It appears that the M.2 adapter is bending towards the eMMC module. I suggest unscrewing the standoff until it is clear of the heatsink, then a few turns more to allow some space between the M.2 adapter and mainboard. At that point, you can hold everything in place, while threading the standoff back into the heatsink. If you don’t overtighten the standoff, there will be a few threads separating the M.2 adapter and the mainboard. This will provide adequate space for the eMMC module.
Hope this helps.


#6

I noticed that 2 short M3 spacers were included with the new shorter M.2 extender card. I figured out that they are intended to be placed in between the M.2 adapter and heatsink, to fix this issue. Unfortunately, the additional support needs to be located in between the m.2 adapter and mainboard, so the M3 spacers would be too long to fit in that location.

So, I didn’t use them and applied the method I suggested to @MarkS, with the M.2 adapter being located midway on the mounting screws (standoff’s threads to others).
With a little care, the M.2 adapter can safely hang midway on the threads of the standoff. It doesn’t need to bottom out on the mainboard and shouldn’t.

A few nylon washers would do the job of ensuring that there is adequate room between the main board and M.2 adapter. Of course, the most ideal solution would be to increase the height of the threaded inserts on the M.2 adapter. But, I suspect that those are only available in the standard height that is being implemented.

Just remembered that the standoff threads are only 10 mm long, so they barely reach into the heatsink. I would also suggest lengthening the threads to 12 mm (same length of the M2.5 screws that I used.)

Hope this helps @Songworks and others. :wink:


#7

I think the best solution is going to be an (or a few) nylon washers.

Otherwise it could get loose over time (a long time) or get tighter if you play around with it.

Yeah I have a little cover on top of the M2 Extender I am not a fiddler but I’m going to try and remove the dust here and there… I have cats so it’s kind of required


#8

Actually, everything is still being held firmly in place by pulling forces between the main board and heatsink, so I can’t imagine that anything will loosen over time. But, there’s no harm in using the nylon washers, if you prefer.

Hmm… not sure what to advise regarding cat hair. Canned air could be useful for occasional cleaning. But, I’d be careful about covering the Rock Pi w/o using cooling fans. Any restrictions to airflow could cause overheating, poor performance, and/or component damage. On the other hand, cooling fans can draw in more hair and deposit it inside the SBC. Perhaps a fan with a filter would work.

Good luck with that. I hope you find a suitable solution.

There are also some case designs (including my own) at the following topic that may be helpful for you.

Best regards


#9

I have 3 cats with medium to long hair and even if I have a case that is closed up (which I don’t) the hair would get in there and the point is it builds up over time on the board. Every now and then I take some non-conductive tweezers and carefully remove said buildup

I haven’t bothered adding a fan as it’s been pretty great with just the small block on the cpu with a little thermal paste. I do mean a little.

My concern is just the eMMC health as I can’t boot off the NVMe directly


#10

There’s a lot of work being done regarding NVMe bootup on:

:sunglasses: