On 08/11/2014 01:04, Tim Newport-Peace wrote:
The difference in dates is EXACTLY 1024 weeks.

This would lead me to believe that possibly the RTC battery on the GPS
Engine (nothing to do with the seal) has expired and while it will get
the correct time, day of the week and week number in the 1024 week
cycle, it does not know which 1024-week epoch it is in.

This is also known to affect Colibri of a certain age.

The solution is to replace the RTC battery and prime the RTC with the
correct epoch.

In practice this may mean replacing the GPS Engine, and considering the
value of the VL, may not be economic.

In the meantime I have heard reports of another two Volksloggers and a
Cambridge of similar vintage with this problem at our club. This is a
high rate of failure in a small population and a short window period.

Somehow I don't think they all just happened to have this battery die at
the same time. More likely these batteries have been dead or dying for a
while and we have just passed some kind of Y2k date threshold which
results in the GPS board defaulting to the wrong "epoch" on the first
fix from a "cold start".

This implies there could be many more devices lurking with this problem
which will come to light when the soaring season warms up in the
northern hemisphere. If you own a logger of this vintage, I suggest you
get it out, switch it on and check what date it logs. If your date is
still good, make a point of powering the logger once in a while to keep
that battery charged!

Ian