Some hints to properly use the HP41c repair kit:
Before all, handle with care. This is a very thin circuit that will not withstand too much handling (as the circuit it substitutes, by the way)
You need a thin, straight, acute but not sharp object to perform the bends around.
You will also need an object to press the circuit around the above object. it should not be too hard or rough or it will damage the circuit
You have bends in both directions (convex and concave) so a good order is required if you don’t want to have impossible bends! Think before doing them. In particular the concave bends between both tabs that form the contacts of the modules need to be done first in my opinion.
you really need to punch the circuit in between circuit pistes with a needle before starting to bend. This has the effect of weakening the circuit support, making it easier to be bent in the line defined by the perforations (make sure you use also your sharp, straight object to line up the holes). Use a magnifier glass, since it is very easy to punch in a circuit piste: the pistes are very close one to another.
The surface of the “donor” battery pack needs to be perfectly flat and clean, if the adhesive is to work properly. You need first to remove the old circuit. it is fixed by small plastic rivets. While the circuit may be torn away easily without damaging the plastic below, you really need to remove all these rivet heads to the base, with a small, sharp blade. Sand away the rest until the surface is flat. It is the only way to ensure that there will be ample space for the adhesive to work. Also, be sure to remove all debris left by your cutting and sanding.
Now, this is the most difficult part. Remove partially the protective paper; start adhering in the valley between the two module connectors. Be sure it is well aligned longitudinally too - a common error. Be sure that as much as possible of the “base” is touching the plastic. The challenge here is to avoid the “sides” adhering before the “floor” is perfect. Press the corners down with a cylindrical object, like the metal pole of a small screwdriver. Above all, don’t use the tip of the screwdriver to push it down, or you will tear some circuit pistes.
Now you can adhere the rest.
while the adhesive is quite good, enhanced durability can be achieved by pasting the extremes with a stronger glue - the one you’re using will be good enough.
Now you can give the “finishing touches”, by bending slightly the battery contacts around its support, so that they mimic close the original battery circuit.
Please write me to firstname.lastname@example.org if you find any problem with it!!