CRS310-8G+2S+ with free flying heat sink

Hardware MikroTik hardware general
1

Got surprise - after CRS310 worked in vertical state (it is allowed state due to we have corresponding wall mount holes on the case) I heard that fan started work much noisier even if no any traffic load. Opened the case and saw this :frowning: :

https://ibb.co/PQS5fYq

Question 1 to Mikrotik team - may be use more robust heatsink mounting instead double-sided scotch tapes which cannot hold good ???

Question 2. Fan connector in the front of fan… it is weird

2

That isn’t a question..

What is weird about it? Standard 4-pin fan power connection. One pin is ground, one pin is power, one pin controls the speed, and one pin reports the speed.

3

Weird because it is quite big and partially blocks airflow from cooler to heatsinks. As result cooler runs on higher speed to compensate this. Just to move this connector 2cm right or left…

4

BTW after my fix my router looks like:
https://ibb.co/n7r6QXv
i.e.

  1. I used special double side scotch for heatsinks
  2. Yes, I made “support leg” using thick scotch like Mikrotik’s do due to no choice, you can see it.
  3. I replaced original plate pin heat sink with square pin one with about same area. Why? It better for airflow (original is placed at 45grad to fan, may be they, designers, tried turn airflow to ventilation holes on the left? Can’t say. But after replacing heatsink temperature actually becomes few degrees lower (may be also because I fix heatsink better than it was before %))
  4. I replaced fan to Noctua one. I know that it performance is less comparing to the original fan (last one is very loud), I even bought 2nd fan and thought install it on left or rear side but after few weeks of usage I see that I needn’t to do this, router is not hot and is very quite %) (it is used mainly as 2.5G VLAN desktop switch)
  5. I noted to never put this router in vertical position %)
5

Thanks! I thought I was the only one with this problem. I suspect half of all CRS310-8G+2S+ has this failure.
Out of the 12 switches I had, 6 had the issue, and the rest is just waiting to fail.
MikroTik has been totally silent about it, and RMA’s running since the start of June has not been answered.
I have a heap of these switches just lying around because they won’t take them in for RMA (as photo evidence like yours is quite clear).
The problem here is that the cooling block rattles around and can break the PCB or short something out. On top of that, the fan goes crazy due to the missing cooling block and could probably cause overheating in hot environment.
Trying to fix it, proved void, as they just dislodged again. They really need some proper heat resistant glue, but that is up to MikroTik.
I really hope they acknowledge this issue soon.

6

I’m really surprised that thermal epoxy wasn’t used in this case.


It’s standard 4-pin PWM connector, you’ll find it in modern PCs too.

https://www.corsair.com/us/en/explorer/diy-builder/fans/what-is-pwm/

7

Before answering randomly, it would be better to read the previous posts first.

It has already been written (on post #2 !!!), and already badly interpreted.

It is very OBVIOUS that it refers to the CAP that forms the connector in front of the fan,
it was enough to make the holes ~2cm further to the right (compared to the photo),
and the air would have had better circulation.

8

This is what i got - a heatsink camping on top of the capacitor. See

http://forum.mikrotik.com/t/warning-crs310-8g-quality-by-issue-with-heatsink-inside-loose/178531/1

9

Just wondering : could a free flying heatsink cause a short-circuit / be a fire hazard? If so they might be at risk of getting this device pulled from the market..
Or am i just talking bs here?

In any case i am going to hold off a new purchase until this is fixed (vertical mount is required for me)

10

PushPinHS.PNG
A couple of extra holes on the PCB and 2x Push Pins would solve this problem.

11

Yes - using 2 extra holes and a push pin solves the issues. The current issues are clearly a design fault. Seems MT used a PCB design bureau that does not have that much experience in this area given the design mistakes (heatsink, fan connector, fan noise). i rather pay 10-15 euro’s more and have this done right from the start than fixing this afterward (and avoid a massive short circuit + potential fire hazards)

Guess i will hold off buying MT switches until this is sorted.