Tsuhan THMPRS-3511-10A SFP on Hex S 2025 (E60iUGS) causes boot-loop

Hardware
1

Setup:

  • Hex S 2025 (E60iUGS)
  • Tsuhan THMPRS-3511-10A SFP for WAN
  • RouterOS 7.23
  • Routerboard firmware 7.23.1
  • The sub 1 A 24 V power supply provided with the Hex S and a 1.5 A 24 V power supply

SFP works when hot plugged

If I hot plug the SFP (Insert the SFP module) after the router has booted, it all works as i should. The router also boots with the SFP working after a soft reboot from CLI.

If power cycled the router goes into a boot-loop

If the SFP is connected when I power up the router, or if I do a power-cycle with the SFP connected the router goes into a state of boot-loop. The blue led lights up, then the connected ethernet leds lights up, then the SFP led, and then it boots again (at least I thing it reboots). Non of the interfaces are available before it reboots.

Is there anything I can do to fix this problem?

2

It depends.

You could have a script that runs (scheduled) "immediately" at boot and disables the SFP.

And another script, running after - let's say - 2 minutes, enabling the SFP.

But if the first script runs soon enough and can actually "catch" the issue has to be seen with tests.

Or, if the script runs, it may force a soft reboot and then the routerOS will boot fully/normally.

Or maybe watchdog can work:

(but it should be already active by default).

3

Thank you for the suggestions.

I have tried to set

/interface ethernet disable sfp1

The Router will still not boot with the sfp module connected. Is there a "deeper" way to disable the SFP?

If not, I can not see that a script can fix this for me.

4

Hi

maybe your PSU is too weak for this combo

when device is UP and you plug SFP module, the stress on PSU is low
but when you power-off whole device with module inserted, and turn back power, PSU may not be enough to start device & sfp at same time

you could try with more powerfull PSU
but if you out of luck, maybe device internal power regulator is problematic

maybe you could try with another vendor SFP module ...

5

Hmmm. Yes, that makes anything "software" inefffective.

To expand on npeca75's suggestion ...

Could it be a "simple" peak of needed current at boot time?

Do you have a "beefier" PSU to try?

The one coming with the Hex S 2025 should be a 24V 1.2A one, you mentioned a "sub 1 A" one.

The Hex S in theory has Max power consumption without attachments 5 W, and Max power consumption 23 W, so - still in theory - 24V 1.2A =24x1.2=28.8 W should be enough to allow for boot time peaks, but you never know.

The Hex S is fine with quite a large range of voltages, 12-57 V, so, any power supply you have around with (say) minimum 40W (24V 2A, 12V 4A, 48V 1A or one of those third party power supllies for notebooks with a zillion connectors and selectable voltage ) are worth a try.

6

I have edited the first post, I forgot to write that I also tried with a 1.5 A 24V supply.

A temporary high power consumption has been one of the things I suspect. I will test it with a lab power-supply and see how much it draws, but I fear that it might be the internal power regulator (as npeca75 suggests) that is the limiting factor.

7

I have tried with a lab-supply, I never "see" it draw over 0.25 W when supplied with 24 V (for either the boot loop with sfp attached, or successful boot without sfp), and it never triggered my limiter set to 1 A. So I do not think it is a power-related issue.

8

Then the only thing you can try doing is to open a support ticket with Mikrotik.