S+RJ10 on CSS326

Hardware MikroTik hardware general
1

I got two CSS326 equipped with a single S+RJ10 in each - just don’t do it.
At first with free ventilation in 22°C ambient the transceivers are running about 95°C.
After two months of operation, ports now start flapping. Transceiver temperature was at 109°C in 24°C ambient.
S+RJ10 were r2, can’t say if r3 is better but doubt that. Mikrotik will get them back.
Hell knows, why they sell this.
If you think about installing these, make sure you have enforced cooling and enough airflow.
On passive devices like CSS326 simply forget that idea. SwOS should not activate them.

/Uwe

2

Yes. Long time ago I read about it. I bought a S-RJ01 and works great on my PowerBox Pro.

One time I believe that I saw that one guy installed heat sinks inside of the module for the same reason. I’m not sure.

Regards.

3

10GBASE-T transceivers all run hot; they use a lot of power, far more than optical ones. I have an Aquantia-based 5Gbps USB adapter, and it gets hot to the touch when in use. And it’s a pretty solid block of metal; I don’t want to know how hot the transceiver itself gets. My S+RJ10s run from 65C to 85C.

4

I can second this. I have a S+RJ10 R1 and can’t see how hot it is. I have it in an CRS317 where it works fine. During the repair of the CRS317 I moved it into a CRS328 together with 3 DACs. It got quite unreliable there, I assume due to lack of coolling. So I am not surprised that it has problems in other switches with dense SFP+ port locations line the CSS326. If you really need to use it in there, add a heat sink so it can be cooled a bit

5

Yep. If you look at the product page for the S+RJ10, it says: “Any MikroTik device with active cooling that has SFP+ ports can now be used … S+RJ10 module is supported also on devices with passive cooling, but may require an extra cooling.” I don’t remember that caveat being there a while ago, and it isn’t in the brochure.

MT is getting a bit careful with those S+RJ10s, it seems…

6

I have never seen a electronic device (with touchable parts) running that hot.
It should have a sign of warning for excessive heat - if you don’t expect it, you really burn your fingers for a couple of days. More than 100°C - man!
How can that be allowed to be distributed? It’s a massive design fail to heat up such tiny thing with 2,5 Watts and not take care of proper cooling. The form factor absolutely does not allow for this.
/Uwe