Can I get replacement batteries for my Norelco 7735X shaver?
I have replaced batteries in several Norelco shavers, typically ending up with better end performance than with the original batteries.
Norelco shavers typically utilize two AA sized NiCad batteries with thin tabs spot welded on each end and the tabs soldered into the circuit board internally.
I have had best success with utilizing Sanyo Eneloop AA batteries, see http://www.google.com/products?q=Sanyo+Eneloop+AA+batteries&hl=en&scoring=p, which are NiMH cells with low self-discharge (i.e. hold their charge for over 6 months) and are free of the memory effects and internal self-shorting problems of NiCad cells.
The key to successfully changing the cells is to leave the original solder tabs on the circuit board and utilize the edge of a single edge razor blade (with great care) rocked back and forth between the metal tab and each of the ends (one at a time) of the original batteries so as to cut the spot weld free from the original batteries while saving the tab.
A single razor blade should do the job, though the blade will now be largely ruined for any further use.
Next carefully flatten the tabs (will be a little deformed by the spot weld break strategy).
Next carefully tin both the tabs and the ends of the new NiMH cells with a small amount of solder.
This tinning is not easy unless you use this strategy: Utilize small drops of "Harris Stay-Clean liquid" soldering flux, a clear (looks like water) zinc chloride liquid flux, e.g. dip a tooth pick into the flux and use just the small droplet of liquid flux which runs off the tooth pick onto the metal. After the flux is where you want the solder, touch a heated soldering iron tip already coated with a tiny amount of rosin core flux for electronic circuit joint soldering to the pre-fluxed area and the metal will easily and rapidly tin with solder.
For the new batteries, use only a tiny droplet of Stay-Clean flux right where you want the solder and touch the costed and heated soldering iron tip to the battery for just 1-2 seconds so as to minimize chances for any damage to the new batteries.
Once happy with the tinning of both the (saved) original batter tabs and the new batteries, hold the new battery in position and briefly touch the soldering iron against the tabs to push it into the battery end and fuse the two areas already tinned with solder.
I does take a little practice to get the above and physical alignments correct. It is helpful, though not mandatory, to use a temperature controlled soldering iron (e.g. set to about 500 F) with a fairly small tip.
Be sure to keep the Harris Stay-Clean flux, even fumes sealed in storage (I usually enclose the Stay-Clean bottle in a clear screw cap larger bottle) because just invisible fumes from this flux on any nearby iron or steel surfaces, over time, will promote rapid rusting. The Stay-Clean is a great product, just be careful with it during handling and storage.
Jan 04, 2010 |
Norelco 7735X Electric Shaver