Connectrix Cisco: Fan speeds run high and do not return to normal limits

Summary: This KB article describes an issue where fan speeds run high and do not return to normal limits.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms

Replace the original Small Form-factor Pluggable (SFP) with a Cisco-compatible long wave Gigabit Interface Converter (GBIC). 

Fan speeds on 9148S models run high after 30 minutes and do not return to normal speeds.

The cause of a fan speed issue is seen as:

  • High system temperature (could be blockage but not necessarily so)
  • Any SFP temp alarm
  • Any system fan failure

There were no observed blockages or impediments.
There were no SFP alarms, nor were there any system fan failures.

Cause

Customer replaced the SFP with a long wave GBIC Cisco-compatible GBIC.
The switch was unable to read the SFP, which caused this fan speed issue.

Resolution

Use a compatible Cisco part. Speed returned to normal limits within 30 minutes upon replacing or removing the SFP.

Affected Products

Connectrix MDS-9148S

Products

Connectrix MDS-9148S
Article Properties
Article Number: 000064622
Article Type: Solution
Last Modified: 20 Mar 2026
Version:  5
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