Hardware Failure

Zscaler ZDX (Digital Experience) smoke smell or burned PCB: Diagnose & Fix

Q: Where can I find the Zscaler official documentation?

https://help.zscaler.com — 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	Zscaler
Operating system	Zscaler Cloud (ZIA / ZPA / ZDX)
Category	Hardware Failure
Skill level	Intermediate to advanced
DIY-able?	Yes with CLI access; some scenarios need Zscaler Support + RMA.

A Zscaler platform behaving badly is usually one of three things: a thermal/PSU issue caught by `trust.zscaler.com cloud status`, a transceiver problem caught by `Connector Health (App Connector / Client Connector)`, or a boot-loader hang you only see on the console. Zscaler Cloud (ZIA / ZPA / ZDX) surfaces all three differently from competitors, so the diagnostic order matters.

I will be honest: on the ZDX (Digital Experience) family I have seen at least one false-positive from the on-box monitoring per quarter. Always cross-check what `Admin Portal → Activation` and `trust.zscaler.com cloud status` reports against the physical front-panel and a smell test of the chassis.

If this is your first Zscaler hardware issue, the good news is that Zscaler Support is competent and the part-replacement RMA cycle is usually under a week for a covered unit.

What this guide covers

Diagnose and recover from smoke smell or burned PCB on a Zscaler ZDX (Digital Experience).

Step-by-step

STOP. Power off the device at the wall before touching it.
Open the chassis and identify which board / module is the source of the smell.
Photograph the visible damage (scorched capacitors, blackened ICs).
Note the device serial number and exact model for the support case.
Do not power back on, burned components fail closed and can damage adjacent boards.
Open a Zscaler Support case with the photos and serial.
RMA the affected component (line card, supervisor, PSU) or the full chassis if the backplane is damaged.

CLI / commands

# Verify hardware state
Admin Portal → Activation
Admin Portal → Administration → Service Status
trust.zscaler.com cloud status

# Collect for Zscaler Support
Client Connector → Help → Export Logs

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 Zscaler Cloud (ZIA / ZPA / ZDX) version?

The procedure reflects current Zscaler Cloud (ZIA / ZPA / ZDX) behaviour. Older releases may need minor syntax adjustments. use the CLI help (? or tab-completion) to verify.

Should I open a Zscaler 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 Zscaler official documentation?

https://help.zscaler.com, 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 Zscaler fix guides → /zscaler/
All vendor guides → /vendors/

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

References

Zscaler support portal: https://help.zscaler.com
Zscaler knowledge base: https://help.zscaler.com
Zscaler security advisories: https://trust.zscaler.com
Open a case: https://help.zscaler.com/submit-ticket

Reference material, not professional advice. Validate against your specific Zscaler Cloud (ZIA / ZPA / ZDX) version and test in a non-production environment before applying.

What changed recently?

Fault diagnosis on a Zscaler 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.

Safety + preconditions

Before any work on a Zscaler device:

Unplug from mains for any internal-access procedure.
Discharge stored energy (capacitors in PSUs, residual battery charge) per manufacturer guidance.
Use ESD-safe handling for boards and modules: no carpet, no wool sleeves.
Avoid moisture; never apply liquids near vents or connectors.
If you smell smoke, see scorch marks, or feel uneven heat, stop and escalate.

Quick verification

Before you walk away from a Zscaler 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 Zscaler 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.