Mechanical Overview; Figure 16. Fan Fault Led Block Diagram - Intel JBOD2312S3SP Hardware Manual

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Intel® Storage Server System JBOD2312S3SP Hardware Guide

The ADT7476 thermal controller on the PDB can measure and control the speed of up to four fans. The

controller provides acoustic enhancements to ensure the fans run at the lowest possible speed for the given

temperature. The controller interfaces with two remote temp sensors and a local temp sensor built into the

chip.

The thermal controller on the PDB is programmed using the SAS expander that comes with the Intel

Storage

System JBOD2312S3SP. The SAS expander in the Intel

Storage System JBOD2000S3SP uses firmware that

programs the thermal controller when the system is turned on. If the SAS expander is not plugged into the

PDB using the I

C cable, the fans will run at 100% and the thermal controller will not be programmed

correctly.

The cable must be connected to the I

C port B (Port C will not program the PDB) on the expander board and

then either of the I

C connectors on the PDB before the system is turned on.

If the fan runs at 100% at room temperature, there is an issue with the SMBUS connection, the SAS expander

is not getting power, or the incorrect firmware is on the expander.

When a fan fails in the Intel

Storage System JBOD2312S3SP, an interrupt register bit is set in the ADT7476

Thermal Controller that signals the fan fault (register shown below). The PMC expander chip on the SAS

expander monitors this register, and when a fan fault bit is set in the interrupt register, this information is

sent to the host system through SES. The ADT7476 controller also sends a signal out of its GPIOs to light the

LED on the failed fan's hot-swap housing which makes replacing/diagnosing the failed fan much easier.

Interrupt Register 2 for ADT7476 (Bits 2, 3, and 4 used for fan faults):

4.2 Mechanical Overview

The physical size of the power supply enclosure is 39/40mm x 74mm x 185mm. The power supply contains

a single 40mm fan. The power supply has a card edge output that interfaces with a 2x25 card edge

connector in the system. The AC plugs directly into the external face of the power supply.

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