Do it yourself: Nothing ventured, nothing gained.

About 15 years ago I bought this Braun shaver, and it served me well for at least 15 years. The rechargeable batteries finally wore out, and I wondered if it would be worth trying to replace them myself rather than pay an appliance repairman ten prices for the privilege.

How to open it? I found a totally useless article on eHow (typical of all these crowdsourced answer sites like WikiHow, FixYa, Yahoo! Answers, and so many others – the blind leading the rutting blind) and then figured out how to get the thing open myself. Once you do, getting to the guts is pretty easy – and the little electronic board with the batteries pops right out. Nice German engineering.

I bought a couple of new NiMH rechargeables, and set about replacing them. The beggar was that those batteries were not soldered to the board, the were spot-welded at the contact points… but with some careful work I was able to get them out.

Popped the new batteries in, and the whole board started to smoke and melt.

Crap. I must have put the new batteries in backwards or something. I thought I was doing it right.

20150415_164000

RIP Braun – It’s the component in the front that really lit up – what looks like burning under the left battery is just residue from the original adhesive.

So this particular attempt at DIY didn’t work out so well… but that’s how I learn. Over the last half-century, I’ve assembled enough handyman skills to install a bathroom into a totally unfinished space, and all of that experience came from just jumping in and doing it. I made mistakes along the way, but these days most things go pretty smoothly.

So I had to run out and get a new Braun (I feel very loyal to that brand, I’ve been using good Braun shavers since 1974, the first one bought in Austria) and hopefully this one will last me at least 15 years, by which time I’ll get my grandkids to buy me a new one for Christmas, so I won’t have to try this particular experiment again.

I’m sure there will be others.

The Old Wolf has spoken.


PS: Ah, the luscious smell of burning silicon…

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9 responses to “Do it yourself: Nothing ventured, nothing gained.

    • Found a great video showing me how to replace the bad CD player in my 2007 prius. So – God willing – I’ll save myself about $1200 by buying an after-market part and installing it myself instead of going to the dealer who wants ten prices.

  1. There can be several things wrong – first, the operating voltage on NiMH is 1.5V and NiCd is 1.25 volts, and that extra half a volt (two cells) can make a huge difference. Are you sure it was supposed to take NiMH?

    Second, you were trying to solder on consumer grade batteries, instead of buying the batteries premade with the spot-welded Nickel foil tabs. You can cook the cell to death trying to get the end tinned and the tab to stick.

    (The right little spot-welder costs a ton, and that takes decades to pay back – unless you want to go into business building battery packs. Buy pre-tabbed.)

    A corollary problem to soldering is melting the thin plastic wrapper around the case, which is the minus anode. The two batteries side by side touching, with mating bare spots on the outside cases and you just short-circuited one of them. This is why the factory ones have heavy jackets or even a cardboard sleeve.

    You may have hooked it up backwards – Sometimes it’s hard to tell on the OEM batteries, but the pinchweld end is usually the positive – and the pinched seam itself depends on a plastic gasket insulator you can cook till that cell shorts out. This is why you /HAVE/ to spot-weld them, the heat stays localized right at the weld spot.

    The ‘component in front’ that cooked looks to be an RF Choke Inductor, just a coil in a ferrite shell.

    I do this every few years in all my Norelcos and never have a problem using factory tabbed cells. Well, except for the one where I stripped a gear on the head drivetrain from waiting too long to change the old heads, but I need another donor to give it’s gears to Science.

    • You know, Bruce – I don’t really care why it went wrong. I don’t go that deep. For me, DIY means “Make it work” – and if I had put the batteries in the right way, it probably would have been a hack job, but kept the shaver going for another 5 years or so. And yeah, they took NIMH. This time, no joy. Next time, probably better luck with whatever I’m shooting for.

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