Sunday, March 25, 2012

Modifying a chinese wall wart for use in Europe

I ordered a USB hard drive case from Dealextreme some time ago, and forgot to check if it has a wall wart compatible with the finnish wall sockets. So of course I got some chinese wall wart with no way of plugging it in anywhere.

Luckily, it accepts the 230V 50Hz AC, it just doesn't physically fit in the socket...

One option would be to buy an adapter, but I couldn't find anything less than 35 euro. Also, even if I found some cheap adapter, it would probably cause power problems to the hard drive case, making the hard drive unstable. So I soldered an europlug cord on the wall wart.

The adapter and the cord, soon to be one.

If you do something like this, please don't have it connected to the wall when you're working on it. At least please don't sue me if some fucking idiot dies like this.

You need some heat shrink tube and a heat gun for this one, to hide the mains voltage connectors totally. You want to make this thing safe you know. If you don't have a heat gun, a hair dryer or a lighter might do.

Soldered together, with heat shrink tubing.

Heat shrink tubes in place.

After applying the heat gun.

A HUGE piece of heat shrink tubing...

At this point I learned that indeed, heat shrink tube shrinks. Especially with bigger tubes, you need to leave some extra length, because it will shrink also in length...

Fuck... Didn't go as planned...

Fortunately, the heat shrink I had at hand fit over the europlug, so I didn't have to start all over. I put a bigger piece of heat shrink on top of the old one and used the heat gun again...

Even bigger piece of heat shrink. This should do it.

...and there we go. Works nicely and safe as fuck!

Finally, ready for use!

Braun 1508 shaver battery replacement

This one might gross someone, but I don't give a flying fuck. If you're offended by imagery of decade-old greasy hairs - of dubious origin - go watch the fucking disney channel.

I don't really use my Braun 1508 shaver that much, I prefer the 3-blade, but sometimes it's a lot of help when trimming the face in a hurry. I've had this shaver for over 10 years, and it's still working nicely for me - but the battery is now long gone. I've just used it plugged to the wall for like 6 years.

Finally, I decided to change the battery. It's just a 1.2V NiMH cell, you can get a new one from literally any grocery store. Here's a guide of how I did it.

First, TAKE OFF THE POWER CORD and keep it that way while working or you'll cease to exist. Then get the screen off and open the two screws on the side.

Open these screws...

After unscrewing them, you have to use some force to get the cover open. There's this white plastic locking mechanism with a spring in it, and that might break. My spring flew somewhere, and I couldn't find it, so in the end I just threw away the white piece of plastic and glued the shawer back together...

The 1580 opened up.

A view of the electronics.

This is the + side of the cell. Remember this. It's important.

...and the negative electrode is connected here.

I took away the cell with some cutters and a bit of force. It's glued in place.

Old cell ripped off the PCB, and the replacement cell.

Then I soldered some wires on the battery. Batteries shouldn't really be soldered on, since the heat will not do them good. But you probably don't have a spot welder at hand. Just use a soldering iron at maximum power and be fast, and it will be fine. The electrical connection doesn't have to be perfect, since it's a low-power circuit.

Wire soldered to the replacement Varta cell - negative electrode.
When soldering don't block the small vents on the positive electrode. They are there to release gas if the cell it overcharged. If they are blocked, the gas will build up and might result in an explosion when charging.

The positive side. Don't block the vents on the cap.

Then solder the wires to the PCB where the original cell was connected. Remember to solder it in the correct polarity, the same way as the original cell.

+ side

The - side.

That's it. Just put the thing back together and the shaver's like new! OK, maybe not brand new, but still, working.

It doesn't really make sense that you need to buy a new shaver when the battery dies. I quess it's partly a safety issue that they don't put a battery slot in the shaver, since it also has mains voltage inside... But mostly it must be the fucking increased shaver sales they get due to dead batteries. So if you have any soldering skills, just fix the thing yourself. You'll prevent generating unnecessary e-waste and save some money from the greedy fingers of Braun.

Fuck you Braun, I win.