Hints: D-Link ADSL router: time to change the power adapter

Sample device: D-Link DSL-2640* (quite old combined ADSL modem / Ethernet switch / Wi-Fi router); should probably work for some other Linux-based routers with Broadcom chips.

Some trouble signs include: red power lights, not booting into the normal working mode (or booting into the recovery one) after power-on; slowing down of the operation, decrease of the performance & significant packet dropping rate; unexpected restarts etc.

Reliable internal software (firmware) symptoms — specific log strings get triggered, e. g.:

• accessed via the web-based interface:

  System Log

  Date/Time	Facility	Severity	Message
  .	.	.	.
  Jan 1 00:01:23	user	warn	kernel: - Power glitch detected. Duration: 5 us

• and via Telnet / SSH:

  ...
  > sh
  ...
  # dmesg
  ...
   - Power glitch detected. Duration: 6 us
  ...
  

  • Note: reportedly, some users also observe another diagnostic log message:

     - Power failure detected. ADSL Link down.

What to do:

1. check the power cabling (and fix it, if needed);
2. check the electrolytic capacitors:
   1. inside the power adapter,
   2. and in the router itself,
   3. and replace (resolder) the blown-up ones with new ones (paying attention to the nominal values, indeed);
3. buy a new power adapter, if needed.

Safety notes:

• BEWARE of electric shock.
• Disconnect the AC power before opening the cases.
• Some technical experience needed.

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Last updated: 2015-11-30