Wednesday, December 26, 2012

Coolpix 990 Battery Door Repair

As nice a camera as it was in its day, the Nikon Coolpix 990 suffers from a design flaw that affects a large fraction of the units that were produced.  The problem is the latch on the battery door.  It involves a little plastic part that eventually fails after years of trying to hold the battery door shut against the pressure of the springy battery contacts.  Once the latch is broken, the batteries won't stay in place, and the camera is essentially useless.

You can have Nikon fix your camera for a zillion dollars, or you can order a replacement part for half a zillion and attempt the repair yourself.  Or, you can try one of the several do-it-yourself ideas that you find on the internet.  The do-it-yourself ideas all seem to take one of two approaches:
  • Repair the latch itself with some sort of microsurgery that involves gluing tiny pieces of metal or plastic inside the camera.
  • Add a plate to the bottom of the camera that will press against the battery door and hold it shut from the outside.
The "fix the latch" ideas all seemed kind of iffy to me, so when my camera broke, I went with the second approach.  Here's the result:

The plate covers most of the bottom of the right-hand side of the camera.  It's attached with a screw that fits into the camera's tripod mount.  The plate then has a 1/4-20 tapped hole in it so the camera can still be used on a tripod with the plate in place.  The slot in the screw is about the thickness of a penny, so all you need is a coin to remove and replace the plate in order to change the batteries.

The image below links to a PDF file with a detailed drawing of the plate and the screw.  The drawing doesn't do a very good job of specifying the oddball curve on the right-hand side of the plate, but that's not very critical anyway and you can more or less just wing it if you decide to make a plate for your camera.

Note: The drawing specifies 5/8" for the diameter of the counterbore for the screw head. The counterbore really only needs to be slghtly larger than the screw head, as shown in the earlier photo.

Monday, December 24, 2012

What to Do with Slippery Glue

Sometimes you have a simple project where you just want to glue a couple of pieces of wood together.  You might not want to mess around with a bunch of fancy joinery, but you probably do want the alignment of the two pieces to be correct.  So you draw some lines on one piece to show where the other piece should go.
Then you smear some glue on both pieces and slap them together.  The glue is so slippery that you can't keep everything in position while you apply a clamp, and even if you could, the squeezed out glue has covered up your lines.  Bummer.
So what you need to do is start over, but this time before you start slinging the glue, clamp an alignment block right next to one of your layout lines, but on the opposite side of the line from where the glued-on piece is supposed to go.
Now you can glue and clamp the parts together and be confident that, as long as the part you're gluing is in contact with the alignment block, it will be in the right place.
Don't forget to remove the alignment block and clean up the excess glue before it hardens!