While the Kobo eReaders have provided pleasure to many people, the devices have some design issues. The user guides and various internet fora give a suspicious amount of attention how to do a soft rest, hard reset, factory reset, paperclip hole reset, etc.
The Kobo Forma device that was presented to me got stuck in a power-on loop in a low-battery state. As a result, the battery could no longer be charged and the device could not be properly powered off. All above instructions on reset methods failed. The Kobo Forma does not have a paperclip reset hole. The device was essentially bricked and was too old to send to Kobo for repair.
So it was time for the last resort: to open the device. WARNING: opening the device will damage the seals that make the device water-tight. The device can be opened by simply bending one of the edges of the rubber backside with slight manual force (as for removing a protective bumper of a smartphone). By chance, I did this in a room with a temperature of about 28 degrees Celsius. In a colder room, you may want to preheat the device to this temperature to make the bending of the rubber and the loosening of the water-tight glue easier. After this, the device looks as follows:
The power leads from the Li-ion battery are directly soldered to the PCB. Because I do not have equipement to handle indium based solder with a high melting point, I decided to simply cut one of the power leads and carry out the following steps:
- connect the device to the charger so that the power-on cycle can be completed (I forgot this the first time as on the photograph)
- remove some isolation from both ends of the cut wire
- wet the clean ends with some fresh solder
- bend the fresh soldered ends so that they run in parallel just a few millimeters apart (but not have them touch each other yet)
- heat one of the ends so that the solder melts
- quickly push, with your finger or some tool, this part of the wire to the other part of the wire while keeping contact between the soldering iron and the two cleans ends until all solder is molten. This step must be done fast and precisely, so that the solder does not oxidize from being heated too long and the power-on cycle of the device is not interrupted by breaking the contact between the wire ends during soldering.
- Isolate the soldered part with some tape to prevent a future short circuit between the power leads (I suppose the Li-ion battery has some protection to prevent a fire during short circuit, but cannot guarantee this).
