GPSrChive Discussion Forum

Have dealt with this issue for years through the course of several Garmin 3-axis units, but my recent experience with a new Oregon 700 has proved more problematic than ever in the past. Sent the following to Garmin today:

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I’ve owned a number of Garmin handheld products with a 3-axis compass chip, and have always had to exercise care about the battery voltage when performing calibration. However, my new Oregon 700 has taken the problem to a new low.

I’m sure that if you dig into your design, you’ll find that a) the compass chip is NOT operating off a board regulated supply, and that b) the chip being used is either unable to be configured for internal regulation, or to save on power, one of the optional internal regulation modes is not selected, and therefore c) the behavior of the chip can and will vary considerably depending upon supply voltage. This results in erratic display of the 3-axis compass heading.

For previous units (e.g., Oregon 450), it seemed possible to perform calibration a short while after a newly charged pair of ‘hot’ NiMH cells had been installed and the voltage allowed to drop a bit, and the performance of the compass chip, noted by consistently displayed headings on the screen, was adequate until the cells neared depletion. Since cell voltage was reasonably constant over the period of use of that pair of cells when I handled things in that manner, the compass performance was not an issue.

However, for whatever reason, I find this workaround for this design issue MUCH more difficult to duplicate on the Oregon 700. It seems the 3-axis chip is responding far more sensitively to supply voltage, making it necessary to recalibrate frequently from the point at which newly charged cells have settled a bit until their depletion. As before, no attempt is made to calibrate with high Vcc of a freshly charged pair of cells, but I cannot find any ‘happy medium’ anywhere in the cell voltage that, after calibration, allows the chip to behave normally for any extended period of time.

I have not directly measured compass performance vs. supply voltage on this new Oregon 700 unit, so I can’t say just how many mV loss it takes after calibration to throw the chip into a tailspin, but if you haven’t already investigated this issue on this or previous models, I’d certainly be prepared to provide the evidence.

I got this apparent non sequitur from Garmin today. Trying to decide how to respond to it. Sigh.
Pondering a reply. I am inclined to return it as defective and see how many iterations we can go through on that game before coming to a different conclusion.

The calibration procedure provided on the device is exactly the same as it has always been.

Hello Chris,

Newer models like the Oregon 700 were calibrated at the factory and don't require re-calibration like the older models did.

Thank you for choosing Garmin,

Chris
Product Support
Garmin International
For 24-hour access to support videos, manuals, FAQs & more, visit the Support Center.

Guess we will see how this plays out. My reply:

So you are saying that your devices have not been and are not now (re the Oregon 700) dependent upon battery voltage for nominal operation of the 3-axis compass?
If so, would you be interested in any evidence to the contrary?
If not, where do I return my Oregon 700 as defective? Purchased through Costco and shipped direct from Garmin only a couple of months ago.

Unfortunately, this is a common occurrence for Garmin technical support. The person responding is frequently unfamiliar with the product they are providing 'technical support' for. I almost always call when absolutely necessary so I can ask for another tech or a supervisor when this sort of thing happens.

Any particular number with which you've had good success? I've never had occasion to call them before.

As this post is in the Oregon 7x0 forum, I would suggest using the contact information provided at GPSrChive > Oregon 7x0 > Troubleshooting.

Indeed, the phone call was the correct move. Thanks for pointing me in a better direction.
Rep located emails, understands the issue, and will be escalating to Engineering for case review.
Have been doing some additional reading

Hi
Did you manage to resolve this issue? I've currently got two Orgeon 700 units which are displaying compass issues. I updated to the latest firmware and then did a full reset on one and all looked good on the compass. I was however out today walking and half way through the walk I realised that something was wrong with the tracking and the heading was erratic. I reset the compass and all was good but obviously this is totally unacceptable as we'd gone completely off track and if I had not realised so quickly we would have had a big issue. This had also happened half way through the previous hike that I had done. How is one supposed to have any confidence in the device if something as basic as a compass / heading does not work?

Regards
Mark

Mgibbons -

Please be more specific about "I realised that something was wrong with the tracking and the heading was erratic."

What were you navigating to and how did it send you the wrong direction?

Hi
Sure. I came to a intersection and pulled out the GPS to check which direction I needed to go. It was unclear as the map did not align with my understanding from a few minutes earlier regarding North and my heading. The GPS seemed to be confused as to which direction was North and "bounced" around as I turned. I opened the compass app and it had North in completely the wrong place: at least 90 degrees out. I recalibrated the compass and it was fine i.e. North was correct, the map made sense and if I turned the alignment to features was correct. I have had this happen a number of times now and also seen the compass essentially "hang" i.e. I open the compass app and if I am static and turn the GPS the compass does not move.

Regards
Mark