What happened to my altimeter?

My Vans altimeter worked great for 155hrs, until today. I attempted to set it to our local AWOS before blasting off for an early evening flight, but I could only get 1/4 turn from the kollsman knob in both directions. It is as if the knob hits a stop both ways. Maybe something internal broke off and is interfering with the knob? Anyone experience this and have a fix? I would really hate to have to buy another one.

Hey Bruce,

My feelings would be that if it's busted, you can't make it much worse! Try the littlle adjusting screw by the knob - loosen it carefully and see if you can get the mechanism to unjam. Of course, you could make it worse....

Paul

You could send it in to an overhaul shop and have them take a look at it, rather than buying new. I've used these guys quite a bit, they have great service and I've always been happy with their products.

If at first you don't succeed, try a bigger hammer!

Bruce,
Mine did the same thing after about 70 hours. Mine was binding between the shafft and the bushing. I just loosened the set screw and gave it a little shot of WD-40 and worked it back and forth. It loosened right up and has been working fine since.

This was of course after I removed it from the panel and took it apart which I did not need to do. Lesson learned!

Thanks everyone! Friday is the next time I can get to the hangar and will try to solve the situation w/out removing the instrument. I'll be sure to post my results.

Here is my current altimeter status:

Put a wrench on the nut under the knob and was able to turn it past the binding portion of the internal gears. I turned it through its full travel a few times and found that there is a distinct binding of the system at one place, but the altimeter and Kollsman are working and accurate after ops checking on a flight this morning. May try lubing it this weekend.

I'm keeping it for now, but realize it may have to be replaced if it gets any worse.