I just thought I would post about a recent repair I performed on my TP-Link TL-WDR4300.

I was using the wrong power supply (a simple transformer + rectifier + smoothing capacitor thing, not a switch-mode power supply), and after a few months, one of the power supply chips on the board failed.  Because it failed low-impedance (and got hot as a result), it was easy to identify.

The chip is an Anpec APW7120.  According to the datasheet, it is rated up to 13.4V in, and anything between that and about 16V is Absolute Maximum territory.  It appears that my crappy WRT54G power supply was supplying a voltage too high for it to handle long-term.

I replaced the chip and it started working again.

The moral of the story is that you should always use a switch-mode 12 volt power supply.  And, no, you also should not power it directly from a car, 12 volt solar power setup, or any other 12V lead-acid setup, because 14.1V > 13.4V.

I dont think so. The linear power supply is not a problem, the problem is that you do not use regulator transistor. When AC input increase, the DC output will be increase, plus rectifier/capacitor DC output will easily overvoltage. That is the problem.