Re: [time-nuts] GPS Week 1536 causing problems?
Anyone else lose an 18x?
I lost one a while ago. Similar. It just stopped doing anything
useful.
Battery failure?
I don't think it has a battery inside. That seems like a poor design. Too
many reasonable use cases would include sitting in a drawer for extended
periods of time.
Mine was less than a year old. It had been plugged in and working fine for
several months. Then it just died.
The things I have been pointing to is to specific firmware bugs or
missfeatures. Doesn't rule out a whole line of other failure modes.
Soft-lockup conditions triggered by external commands or electrical
events included.
A firmware bug would explain things. So would a loose connection. It was
just sitting there working when it died, so I don't expect that anything
strange electrical or mechanical happened.
As I was poking around, double checking things to make sure I didn't inject
too much noise into this discussion, it started working again.
It could be the firmware recovered or maybe I jiggled a loose connection back
together.
In case it dies again... Does anybody know how to take one of them apart?
The case is hard plastic with no obvious screws. The bottom has a layer of
tough non-skid, non-scratch rubber/plastic. I have peeled some of it back
(hard work) but I haven't found any screws yet. They may be under the
magnets which are either glued in or snap into their holes.
--
These are my opinions, not necessarily my employer's. I hate spam.
Hal Murray wrote:
I don't think it has a battery inside. That seems like a poor design. Too
many reasonable use cases would include sitting in a drawer for extended
periods of time.
There is a battery inside. A tiny little Panasonic rechargeable lithium
cell. Mine were at 2.7V.
Mine was less than a year old. It had been plugged in and working fine for
several months. Then it just died.
Six months. The most recent component is dated 0751, so they've been in
storage for a while before I got them.
As I was poking around, double checking things to make sure I didn't inject
too much noise into this discussion, it started working again.
I discharged the batteries on my pair. 0.6V was not low enough, then I
tried again with a dead short for a few minutes, and they both came
alive again. So just discharging in the drawer for a month or two might
bring it back to life.
So I support the 'yet another buggy firmware' theory. MediaTek.tw does
not give me a warm fuzzy feeling.
In case it dies again... Does anybody know how to take one of them apart?
The case is two cups. The top has two 'rings' 2mm apart, the outer ring
being the outside of the top. The bottom also has two rings, 1mm smaller
than the top. The cavity between the two rings on the bottom is filled
with silicone before the top is pushed on. It is held in place with 3
snap locks, one of which is right next to the thickest bulge on the
strain relief. If you insert a flat screwdriver and pry the top up
exactly opposite that bulge, you can get the silicone to release and
it's then relatively easy to see where the snaps are. Apply force.
If you have compressed air, pull off the bottom label, pull the green
seal off the breather hole, and apply compressed air.
The magnets are glued on from the inside, there's nothing on the outside.
(and on a side note, the tiny little TCXOs in them are both ~1.4 ppm low)
/Kasper Pedersen
Hal Murray wrote:
Anyone else lose an 18x?
I lost one a while ago. Similar. It just stopped doing anything
useful.
Battery failure?
I don't think it has a battery inside. That seems like a poor design. Too
many reasonable use cases would include sitting in a drawer for extended
periods of time.
Providing an RTC has benefits, especially when considering week-rollover
issues, since when the receiver wakes up it has no idea of date at all,
pulling in the RTC time and date is a sufficient hint, and adjusting
with detailed info from the GPS is a trivial extention. Then adjusting
the RTC is not a hard thing to do every once in a while. The same
problem could also be solved using EEPROM space. A byte would suffice.
Many of the GPS OEM boards I have seen has support for RTC battery. Is
also used to keep CMOS for waypoints.
Cheers,
Magnus
In message: 4A52BD4F.5020000@rubidium.dyndns.org
Magnus Danielson magnus@rubidium.dyndns.org writes:
: Hal Murray wrote:
: >>>> Anyone else lose an 18x?
: >
: >>> I lost one a while ago. Similar. It just stopped doing anything
: >>> useful.
: >
: >> Battery failure?
: >
: > I don't think it has a battery inside. That seems like a poor design. Too
: > many reasonable use cases would include sitting in a drawer for extended
: > periods of time.
:
: Providing an RTC has benefits, especially when considering week-rollover
: issues, since when the receiver wakes up it has no idea of date at all,
: pulling in the RTC time and date is a sufficient hint, and adjusting
: with detailed info from the GPS is a trivial extention. Then adjusting
: the RTC is not a hard thing to do every once in a while. The same
: problem could also be solved using EEPROM space. A byte would suffice.
Usually, you're right. There's one case that might make it not
suitable.
Many contracts require spares for all the important gear. Long
storage times makes storing the last known date ineffective. Of
course in this case "long" is on the order of 9-odd years. This may
be good for many applications, but not necessarily ones that have 10
or 15 year deep spares requirements...
Warner
Hi 18X owners
I experienced same problem with my fleet of 16HVS (originated from Kit
Scally ?).
The non functioning GPS is not on Garmin PVT mode, neither NMEA mode !!!.
Reconfigured by using SNSRCFG software switch to NMEA or Garmin mode, my
16HVS is back to business.
http://www8.garmin.com/support/collection.jsp?product=010-00321-05
Pascal
On Tue, Jul 7, 2009 at 1:48 PM, M. Warner Losh imp@bsdimp.com wrote:
In message: 4A52BD4F.5020000@rubidium.dyndns.org
Magnus Danielson magnus@rubidium.dyndns.org writes:
: Hal Murray wrote:
: >>>> Anyone else lose an 18x?
: >
: >>> I lost one a while ago. Similar. It just stopped doing anything
: >>> useful.
: >
: >> Battery failure?
: >
: > I don't think it has a battery inside. That seems like a poor design.
Too
: > many reasonable use cases would include sitting in a drawer for
extended
: > periods of time.
:
: Providing an RTC has benefits, especially when considering week-rollover
: issues, since when the receiver wakes up it has no idea of date at all,
: pulling in the RTC time and date is a sufficient hint, and adjusting
: with detailed info from the GPS is a trivial extention. Then adjusting
: the RTC is not a hard thing to do every once in a while. The same
: problem could also be solved using EEPROM space. A byte would suffice.
Usually, you're right. There's one case that might make it not
suitable.
Many contracts require spares for all the important gear. Long
storage times makes storing the last known date ineffective. Of
course in this case "long" is on the order of 9-odd years. This may
be good for many applications, but not necessarily ones that have 10
or 15 year deep spares requirements...
Warner
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M. Warner Losh wrote:
In message: 4A52BD4F.5020000@rubidium.dyndns.org
Magnus Danielson magnus@rubidium.dyndns.org writes:
: Hal Murray wrote:
: >>>> Anyone else lose an 18x?
: >
: >>> I lost one a while ago. Similar. It just stopped doing anything
: >>> useful.
: >
: >> Battery failure?
: >
: > I don't think it has a battery inside. That seems like a poor design. Too
: > many reasonable use cases would include sitting in a drawer for extended
: > periods of time.
:
: Providing an RTC has benefits, especially when considering week-rollover
: issues, since when the receiver wakes up it has no idea of date at all,
: pulling in the RTC time and date is a sufficient hint, and adjusting
: with detailed info from the GPS is a trivial extention. Then adjusting
: the RTC is not a hard thing to do every once in a while. The same
: problem could also be solved using EEPROM space. A byte would suffice.
Usually, you're right. There's one case that might make it not
suitable.
Many contracts require spares for all the important gear. Long
storage times makes storing the last known date ineffective. Of
course in this case "long" is on the order of 9-odd years. This may
be good for many applications, but not necessarily ones that have 10
or 15 year deep spares requirements...
I agree that they are not suitable for that type of application.
However, it does not make the battery unsuitable for GPSes as such,
which was the point I was trying to make. How and if this detail springs
to mind for any particular vendor is the issue. A flakey RTC may be more
of a problem than a live one or a dead one.
Cheers,
Magnus