Start-Up Sequence; Troubleshooting Tips; Rule Out Rf; Leds And Error Conditions - Motorola SB6121 Quick Reference Manual

Quick Reference Guide: Motorola SB6121

Start-Up Sequence

The SB6121 goes through a series of steps when first connected to power and RF signal.
The SB6121 start-up steps are:
A. Power On Self Test (POST). If LED remains off, modem is faulty.
B. Scanning downstream frequencies.
C. Scanning upstream frequencies.
D. Downstream and upstream acquired. Modem processing for DHCP, TFTP, and TOD.
E. Ready. PC/Activity is solid when a CPE is connected and blinks when transmitting or
receiving data.
F. Powered off.
G. Modem is successfully registered but Network Access Control (NACO) is disabled via
DOCSIS® configuration file.
H. Performing firmware upgrade
DOCSIS 3.0 modems have dual-colored LEDs to visually determine if channel bonding and
Gigabit Ethernet is enabled.

Troubleshooting Tips

Rule out RF

Use the front panel LEDs as well as a SLM to rule out potential signal issues. If the RF levels are
acceptable, most issues can be corrected by restarting the cable modem. To restart the Motorola
SB6121:
1. Shutdown the computer
2. Unplug the cable modem from power and wait approximately 1 minute.
3. Plug the cable modem back into power.
4. Observer the LED light up sequence as detailed above.
5. Restart the computer.

LEDs and Error conditions

Light Turns off during Startup:
RECIEVE The downstream (RECEIVE) channel cannot
be acquired.
SEND The upstream (SEND) channel cannot be
acquired.
ONLINE IP registration was unsuccessful.
POWER Verify the power connection.
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Turns off during normal
operation:
The downstream channel was
lost.
The upstream channel was
lost.
IP registration was lost.
Verify the power connection.
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