Roomba Discovery FET Upgrade
A common failure of the Roomba Discovery model is the internal battery charger.
There are 2 FETs involved with the charger, U2 and U4.
The original part is an STN3PF06
P-channel 60V 0.18ohm 2.5A SOT223. The STD10PF06 is a P-channel 60V 0.18 ohm 10A DPAK.
It is a bigger package, but the Gate & Source leads are the same spacing and
configuration as the SOT223 package.
Shown above, the DPAK FET, the original FET, and a 1/8" x 5/16" piece of copper.
For U2, attach the piece of copper as shown below.
Use a piece of insulation tape under the copper after soldering it.
The new FET in place.
For U4, attach the piece of copper as shown below.
The copper can touch the big diode.
The new FET in place.