Need to change memory battery in Skymap III...

Replacing the Bendix/King Skymap IIIC internal battery is not a big deal if you know one end of a soldering iron from another. I did mine back in 2005, took about an hour. It seems that if it is 4+ years old you are on borrowed time. Mine lasted 5 1/2yrs from first use.

One irritation is that you will lose all user waypoints etc as this battery is what keeps them alive and kicking. Also, the unit doesn’t give much warning that the battery is about to go to the great recycling center in the sky. So it will invariably quit in marginal VFR away from home – or at least it did with me – and then the unit will not function, even with external power. The blue screen of death….

Get set up on a clean table with good light and a magnifying glass (for those 40+). The battery is buried under a couple of pc boards in the unit, which need to be removed carefully. You’ll find the battery lurking in the depths, soldered to one of the boards. It’s AA size, but it is a 3.6v lithium cell with a wire soldered on each end. Make sure that both you and the unit are grounded to avoid static damage. A solder ****** helps to clean out the holes in the board.
The battery is readily available from Digikey, or possibly a local electronics store, for $5-10. Have it in hand before you open the Skymap. This (or similar) is what you want.

http://www.digikey.com/scripts/DkSearch/dksus.dll?PName?Name=439-1015-ND&Site=US
http://rocky.digikey.com/WebLib/Tadiran%20Batteries/Web%20Photos/TL-5903%5EP.jpg

If any of the foregoing has you puzzled – you’d better send it to Honeywell/BK.
Not sure what Honeywell/BK charge, but I bet you can buy a few gallons of gas instead if you do it yourself. My view is that I will replace the battery every 4 years or so at my convenience (make a logbook entry so you remember). That way you can download the waypoints etc to a PC, reload them afterwards, and be reasonably assured that the battery won’t die at an inconvenient time. See Matt "Matronics" Dralle’s program to upload/download data:

http://www.matronics.com/skycomm/

The Skymap is a bit long in the tooth these days; there are better/faster/cheaper units now, but it still tells me everything I need to know in living color, so it’s worth a small amount of effort to keep it running. The screen is dim in bright sunlight, but still readable, and I believe that BK recently dropped the price of the data cards to a more reasonable price.