My slightly obsolete Garmin GPSMap 441 has been displaying a little memory loss similar to myself. Whenever it's powered off it forgets "time and place", reverts to 1999 and has to get a new fix on position. I thought it must have a battery like the CMOS on a computer so I googled and found no reference to a battery for this model. I took it apart last night and no battery I could find, just 2 capacitors ? Wife says replace but since it takes me a few minutes to remember where and when I am every morning I have some sympathy for it. Also a new one opens up a can of "upgrade" worms. Any thoughts ?
Chartplotter with dementia
- Thread starter Calif. Ted
- Start date
These devices will often have an integrated real time clock (RTC), that is often powered by a cap. It holds time when the device is off to facilitate a faster fix. If you leave the device off too long and the the cap runs down it will exhibit that behavior. Or if the cap is shot, then you’ll always get that.
Correct. If a device knows the time/date, and if that time date is within (say) a week of when it was last used, it can do a 'warm start' to get a faster fix. It also relies on being within 150 miles or so from where it was last used. Doing this it will often get a fix in 20 seconds or less.
If one or more of these items are not true, the device will 'cold start', doing a systematic scan to find the birds by listening on ALL potential doppler-shifted frequencies. This can take several minutes.
Could this be related to the April 6 rollover?
https://support.garmin.com/ms-MY/?faq=zWQY6Z2kFiAuY9kDnDBgZ6
https://support.garmin.com/ms-MY/?faq=zWQY6Z2kFiAuY9kDnDBgZ6
Jackdaw seems to have it nailed, I found it curious yesterday that after resetting time and shutting down when rebooted 5 minutes later it had only lost a year.
It does only affect celestial not navigation as Capta noted, I first noticed this winter that my ETA's to a waypoint were 1 hour off. Obviously not recognizing DST, but I didn't remember having to reset in the past and thought it should be getting a time signal anyway. One day I went into celestial to check sundown/moonrise when I finally noticed the date was 20 years ago.
It's only tied to the AP but I never steer to a waypoint anyway. I only have DSC on handhelds, no AIS, no radar, no NMEA 2000 anything, so a CP with a bunch of new capabilities might trigger a desire for that $600 wireless wind transducer, DSC station radio, AIS etc. etc.
BTW now that DST is gone, the ETA's are correct as it defaults to August.
It does only affect celestial not navigation as Capta noted, I first noticed this winter that my ETA's to a waypoint were 1 hour off. Obviously not recognizing DST, but I didn't remember having to reset in the past and thought it should be getting a time signal anyway. One day I went into celestial to check sundown/moonrise when I finally noticed the date was 20 years ago.
It's only tied to the AP but I never steer to a waypoint anyway. I only have DSC on handhelds, no AIS, no radar, no NMEA 2000 anything, so a CP with a bunch of new capabilities might trigger a desire for that $600 wireless wind transducer, DSC station radio, AIS etc. etc.
BTW now that DST is gone, the ETA's are correct as it defaults to August.
Oh I've got wind and yeah, you'll never catch me pointing a flashlight at the windex at night again. But it's Ray, old Ray, just got a new $375 transducer in fact. Looking over all the cool "Sailing" features on a new Garmin leads me to believe I need their transducers and inputs and it might not want to listen to any Rayspeak. I'll have to do some research.
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My Garmin GPS12, the older of my GPSs, is working fine after the roll-over. The date is the only thing not working. It is showing Aug '99 with the date starting on the 21st (which corellated to April 6). 21 Aug 1911 was the date of the last roll-over. So this GPS is good but the date will always be off.
My Garmin GPS72 did the roll-over just fine. Everything is correct. But it too is slow to start. I found out that this GPS has a backup battery in the unit. Probably needs to be replaced. Maybe other than a cap, you have a small button battery.
Capacitors are designed to hold a charge while the device is shutting down. This to close any files. They are not designed to hold a long term charge. Although I am sure some devices have them, I think button batteries are really the correct solution.
My Garmin GPS72 did the roll-over just fine. Everything is correct. But it too is slow to start. I found out that this GPS has a backup battery in the unit. Probably needs to be replaced. Maybe other than a cap, you have a small button battery.
Capacitors are designed to hold a charge while the device is shutting down. This to close any files. They are not designed to hold a long term charge. Although I am sure some devices have them, I think button batteries are really the correct solution.