As I started testing LEDE/OpenWrt in ARV7510PW22 for the first time I noticed it overheats more than accepatble and its WIFI for some reason gets stuck and sometimes gets disabled after a few minutes of usage. At first, I suspected its RaLink Wifi chip but after a few tests it turned out an overheating issue.
With this digital thermometer its CPU reached more than 52°C and was still climbing up.
I grabbed a PC fan rated 12v / 0.13A.
Made an opening in router's back. Glued the fan.
Then I made a power connector with male in one side and female in the other. I didn't want to solder the fan directly in the router's power input.
This router needs 15v / 1.20A. The charger I use is rated 15v / 1.66A. The fan is rated for 12v / 0.13A. So it's better to step down that 15v for the fan and make it 12v.
Ohm's Law to the rescue: (15v - 12v) / 0.13A = 23 Ohms.
However, with 12v it's a bit noisy, so I needed more resistance. I combined a 22 Ohm + 47 Ohm resistor in serial.
And that's all. I'm using it and stressing it under heavy load. So far so good ;)