Any one else with a Cobalt finding the compass less than reliable? Mine is either very messed up or I'm diving with highly magnetized steel cylinders. North is stuck over my right shoulder regardless of how I turn myself around. Calibrated and re-calibrated repeatedly; works at home; get the gear on and it's stuck. My wife's Suunto Viper Air compass works fine.
This is really aggravating because other than this issue, the Cobalt is a fantastic product.
--Tracy
Sorry I missed this post earlier- I'll try to help get you pointed in the right direction
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I doubt the cylinders have much effect unless you are holding the computer right up against them, though I have seen some pretty magnetic cylinders, so I won't rule that out completely. That is something you could check at home, to see if moving the compass around the cylinders deflects the reading- it should not do so noticeably until you get quite close to the steel- as it would with any magnetic compass. There is most likely an issue with the calibration- possibly the initial calibration done at the factory. Please forgive me if some questions or suggestions seem obvious, but I want to eliminate any easy fixes first.
Has the compass ever worked while diving- i.e. with all you gear on- as you would expect? You mention that it seems to work at home after calibrating- does it
really work, that is to say, does it still properly indicate north, or east, or south if you are holding it upside-down or sideways? Large shifts in reading direction with a change in orientation is a sign something is wrong. If it's really working well in one spot and does not work at a local dive site, then we have to suspect something in the gear or environment is deflecting it, and that's pretty unlikely.
It is important that the calibration be done as carefully as possible, rotating the 180° steps with reasonable accuracy- I fasten mine in a small box and rotate the box using a table edge to check against. It can be done with just the Cobalt if you have a flat surface, a reference line, and are careful. Also- just to make sure- there should not be large lumps of ferrous metal in the vicinity- a wooden tabletop is fine, a metal one will throw it off. As might metal legs or large metal fasteners. Sometimes metal can surprise you- I found (by experience) that I can't calibrate the compass on the kitchen counter directly above the dishwasher, because the magnets in the motors throw off the compass. Try to vary the spot where you calibrate it and see if anything changes.
Again, apologies if this is obvious, but if your trip to the dive site involves, say, flying several thousand miles to the south, you would need to recalibrate at the destination- calibration is an adjustment to the local magnetic field.
So... if you are doing, or have already tried, all of the above and the compass still seems stuck reading inaccurately, then I suspect an error in the initial calibration- this is done in a jig at the factory, and sets the gain and offset for the various axis of the compass and accelerometer. While in a pinch it would be possible to do this in the field (and I can help if you are stuck), by far the best option would be to send it back to Atomic to be redone- and at that time they could ensure that the compass chip itself is OK. I did come across one other individual that had an initial calibration error.
The compass should work within at least the range of accuracy that you would get with an analog compass, and do so when held at any angle. It it's not doing that then something is wrong.
Please let me know what you see, and if you want to return the Cobalt for recalibration.
Ron
