Posted: Sat Nov 19, 2011 23:03 Post subject: Passive PoE mod for TP-LINK TL-WR741ND
Hi all,
Here is how you can mod your TP-LINK TL-WR741ND (V2.0) for passive PoE.
1) Open the device by removing the rubber feet and the screws behind them at the indicated positions. Once done, pull both the upper and the lower half of the case gently apart.
2) Remove the SMD resistors R6 and R7.
3) If you plan on running the router with voltages higher than 12VDC (see below), you must upgrade the caps. Use the same capacity, but 25V types instead of the original caps. Observe polarity!
4) Solder some wires to the Pins 4/5 + 7/8 of RJ45 connector for LAN port 1. Run the wires to the indicated positions. Wiring as shown below is for positive (red wire in pic) on brown/brown-white and negative (black wire in pic) on blue/blue-white wires of the ethernet cable and will bypass the power switch. Observe and double-cross-check polarity before connecting to your PoE injector/switch! The power supply circuitry on this router does not have reverse polarity protection.
That's about it.
Note that the power supply chip in this router will accept up to 20VDC. However, if you plan on feeding more than 12VDC, you must upgrade the caps to 25V or higher rated types! I have done my tests with 12VDC supply voltage only.
Also, do NOT ever feed AC power to the router! Doing so will destroy the device!
Oh. Of course, you do all of this at your own risk. Neither I nor dd-wrt.com nor anyone else can be held liable for any whatsoever damage resulting from this mod or your interpretation thereof, etc blah blah blah.
Cheers
gridrun
Last edited by gridrun on Sun Jan 01, 2012 21:38; edited 3 times in total
Thinking of buying one of these and doing this. Just a quick one, what is the purpose of removing the 2 resistors? Do they link your now PoE pins something else in the circuit? Or something ridiculous like down to ground?
Thinking of buying one of these and doing this. Just a quick one, what is the purpose of removing the 2 resistors? Do they link your now PoE pins something else in the circuit? Or something ridiculous like down to ground?
The resistors go between the wires of each unused pair, instead of just shorting them together. IIRC, that's the standard. Prevents high currents from flowing (by induction).