How do you change battery in braun 5742?

Answer 1

Braun 5742 disassembly:

1. Remove the cutter screen.

2. Remove the cutters.

3. Use a #8 Torx screwdriver to remove the two screws on the cutter frame. Lowes hardware sells a really cheap Kobalt brand Torx screwdriver with multiple Torx bits. Note that there are small O-rings (orange colored on my shaver) around each screw which you are removing now, around other screws which you will remove later, plus O-rings around the metal power jack posts. Pay attention and do not lose these O-rings. If you do lose one and can't find it, use a small dab of contact cement when reassembling your shaver in order to achieve the same watertight seal where the missing O-ring would be.

4. With the sideburn trimmer retracted, pull on the entire cutter assembly. It helps to pull somewhat more on the side of the cutter frame adjacent to the sideburn trimmer assembly, or at least pull that side of the cutter frame assembly slightly loose first by about one eighth of an inch. It may take some tugging to pull the cutter frame off of the shaver body since Braun uses some sort of silicone based sealant compound to assure that the razor is watertight. Then simply pull off the entire cutter frame.

5. Clean the gasket areas of the cutter frame and shaver body with Q-tips and isopropyl alcohol so that these mating surfaces will be nice and clean when you later reassemble your shaver. A can of compressed air is also handy in order to assure that there is no lint remaining on these mating surfaces. And yes, put on your eyeglasses so that you can see what you are doing!

6. Insert a very small jewelers flat head screwdriver into one of the rubber plug covers over the hidden screws at the rear end of the shaver body and pop out the rubber cover. The screwdriver should be inserted along the side of the cover closest to the power jack. Alternatively you probably can use the straightened out end of a small paper clip instead of a jewelers screwdriver since the rubber plugs are purely cosmetic in function. Do the same for the other rubber plug.

7. Remove the two screws hidden under the rubber plugs.

8. Hold the shaver horizontal and use the eraser end of a pencil to push on one or more of the metal posts in the shaver's power jack. The guts of the entire razor will slide forward inside the shaver case towards the cutter end.

9. Grasp the cutter head end of the shaver guts and simply finish pulling the guts out of the shaver case.

10. Remove each NiCad battery by prying up on the end of the battery which is nearest the plug end of the shaver guts. The pin built into the end of the battery will unsnap and slide up through the channel of the shaver's battery terminal. Note that there is a small band of double-stick adhesive tape underneath the batteries. Roll the battery back and forth and use a jewelers screwdriver to pry the tape away from the battery. Then extract the battery. Do the same for the other battery. Use the jewelers screwdriver to reposition, if necessary, the double-stick tape back onto the frame of the shaver.

11. The NiCad batteries create a fair amount of oxidized film over a few years on the battery posts and on the battery terminals inside the shaver. This film prevents electricity from easily flowing between the battery posts and the terminals. An indication of this condition is that your razor never indicates that the batteries have fully charged. Clean the ends of the batteries by thoroughly wiping them with a cloth slightly dampened with isopropyl alcohol and then clean again with a dry portion of the cloth. Do the same, using Q-tips, for the battery terminals in the shaver frame.

12. If you have already bought replacement NiCad batteries, install them now. If you wish to test the original batteries in order to see if they will take a full charge now that you have cleaned off all oxidation, reinstall the batteries and press the shaver's power button. The shaver's charge light should glow red for several seconds. Then plug in the charger, wait an hour, and see if the charge light is blinking. A blinking light indicates that the shaver electronics have sensed that the batteries have reached a full charge.

Reassembly:

1. Reassembly is the reverse of the disassembly procedure above, but with one additional procedure which must be done before installing the cutter frame: After reinstalling the shaver guts and before installing the cutter frame, make sure that the sideburn trimmer is retracted. Then orient the small spinning brass post on the end of the shaver guts such that the brass post is furthest away from the sideburn trimmer. If the cutter frame does not easily snap onto the shaver body or does not seat fully, then the orientation of this brass post is the problem.

Answer 2

take the bottom off than put a new battery in