Hardware Failure

Nvidia (Mellanox) SN3420 stack member missing: Diagnose & Fix

Q: Where can I find the Nvidia (Mellanox) official documentation?

https://docs.nvidia.com/networking/ — search the product family + feature name.

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

⚡ At a glance

Vendor	Nvidia (Mellanox)
Operating system	Cumulus Linux / NVOS / SONiC
Category	Hardware Failure
Skill level	Intermediate to advanced
DIY-able?	Yes with CLI access; some scenarios need Nvidia Enterprise Support + RMA.

Hardware-class faults on Nvidia (Mellanox) kit fall into a tidy little matrix once you have seen a few. Cumulus Linux / NVOS / SONiC gives you the building blocks via `nv show system` and `nv show platform environment`; the rest is pattern matching. The SN3420 platform is one of the more common offenders only because the install base is large.

Do not skip the visible-and-audible inspection. Burnt-PCB smell and fan-tray rattle are diagnostic signals that no command will ever surface. I have caught more dying PSUs by ear than by `nv show platform environment`.

If the chassis is dark and the console is silent, jump straight to the PSU/cable substitution path before opening a Nvidia Enterprise Support ticket, it eliminates the most common cause in under five minutes.

What this guide covers

Diagnose and recover from stack member missing on a Nvidia (Mellanox) SN3420.

Step-by-step

Run the stack / chassis status command to see member states.
Inspect the stack cables. re-seat both ends.
Try replacing one stack cable at a time to identify a bad cable.
Power-cycle the affected member if cables are good.
If the member still doesn't rejoin, RMA it.

CLI / commands

# Verify hardware state
nv show system
nv show platform inventory
nv show platform environment

# Collect for Nvidia Enterprise Support
cl-support (Cumulus) / show techsupport (SONiC)

When to RMA

Repeated failure after re-seat and power-cycle
Visible burn, scorching, or physical damage
POST or memory diagnostic failure
Hardware crashinfo without a software workaround

Frequently asked questions

Will this work on my specific Cumulus Linux / NVOS / SONiC version?

The procedure reflects current Cumulus Linux / NVOS / SONiC behaviour. Older releases may need minor syntax adjustments, use the CLI help (? or tab-completion) to verify.

Should I open a Nvidia Enterprise Support case immediately?

Open one if you suspect hardware failure or the symptom persists after a maintenance-window reload. Make sure your support entitlement is active first.

Where can I find the Nvidia (Mellanox) official documentation?

https://docs.nvidia.com/networking/: search the product family + feature name.

Is this procedure safe in production?

Test in a lab or maintenance window first. Capture pre-change state so you can roll back.

All Nvidia (Mellanox) fix guides → /nvidia/
All vendor guides → /vendors/

Related guides worth a look while you sort this one out:

References

Nvidia (Mellanox) support portal: https://enterprise-support.nvidia.com/
Nvidia (Mellanox) knowledge base: https://docs.nvidia.com/networking/
Nvidia (Mellanox) security advisories: https://www.nvidia.com/en-us/security/
Open a case: https://enterprise-support.nvidia.com/s/createcase

Reference material, not professional advice. Validate against your specific Cumulus Linux / NVOS / SONiC version and test in a non-production environment before applying.

What changed recently?

Fault diagnosis on a Nvidia device goes faster when you map the symptom to a recent change:

Did firmware update in the last 7 days?
Did the network (router, ISP, VPN) change?
Was the device moved physically?
Did paired devices (phone, hub, app) update?
Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Before you start

A few things to confirm so the Nvidia device fix goes cleanly:

Latest firmware downloaded if you're going to update.
Warranty + support contract status checked, opening sealed parts may void it.
Backup of current configuration (where applicable) taken.
Spare parts on hand if you anticipate replacement.
Adequate workspace, lighting, and time. rushing causes regressions.

Quick verification

Before you walk away from a Nvidia device fix, run through:

1. Reproduce the original trigger, does the issue reappear? 2. Check the device's status / health screen for any new alerts. 3. Confirm paired devices (app, hub, controller) reconnected. 4. Save / commit any configuration changes per the device's normal workflow. 5. Note the change in your maintenance log with date + firmware version.

When to call Nvidia support instead

Escalate if:

The same symptom returns within 24 hours of a clean fix.
You see physical damage (burn marks, swollen battery, cracked PCB).
The device is in warranty and a hardware replacement is the cheaper outcome.
Repair requires specialised tools you don't own (alignment jigs, calibration software).
Following the official path keeps the warranty intact, which matters more than the time spent.