Cambridge GPS NAV problem, need help

[Morteza Ansari]

Hi,

I recently bought a glider and it has a GPS-NAV unit with a GPS20 in
it. It seemed to work fine when I bought it, but this weekend I
powered it up and it comes up with a "GPS Fail Press ON Key". When I
press the "ON" key, it just goes through the cycle again and comes
back to the same page.

It is running LCD version 5.3E, GPS version 6.0. The initial screens
all look good including the internal battery voltage (3.0v).

Any ideas or suggestions?


Cheers,
Morteza

[Darryl Ramm]

On 9/25/11 10:04 PM, Morteza Ansari wrote:
> Hi,
>
> I recently bought a glider and it has a GPS-NAV unit with a GPS20 in
> it. It seemed to work fine when I bought it, but this weekend I
> powered it up and it comes up with a "GPS Fail Press ON Key". When I
> press the "ON" key, it just goes through the cycle again and comes
> back to the same page.
>
> It is running LCD version 5.3E, GPS version 6.0. The initial screens
> all look good including the internal battery voltage (3.0v).
>
> Any ideas or suggestions?
>
>
> Cheers,
> Morteza

Almost certain to be cabling, corrosion, bent/abused pins in the telco
connectors. Also RTFM for the Model 20 and make sure the LED on the
Model 20 tells you it has a GPS signal/lock.

Darryl

[Morteza Ansari]

On Sep 25, 11:13*pm, Darryl Ramm > wrote:
> On 9/25/11 10:04 PM, Morteza Ansari wrote:
>
>
>
>
>
>
>
>
>
> > Hi,
>
> > I recently bought a glider and it has a GPS-NAV unit with a GPS20 in
> > it. It seemed to work fine when I bought it, but this weekend I
> > powered it up and it comes up with a "GPS Fail *Press ON Key". When I
> > press the "ON" key, it just goes through the cycle again and comes
> > back to the same page.
>
> > It is running LCD version 5.3E, GPS version 6.0. The initial screens
> > all look good including the internal battery voltage (3.0v).
>
> > Any ideas or suggestions?
>
> > Cheers,
> > Morteza
>
> Almost certain to be cabling, corrosion, bent/abused pins in the telco
> connectors. Also RTFM for the Model 20 and make sure the LED on the
> Model 20 tells you it has a GPS signal/lock.
>
> Darryl

Thanks Darryl, I brought it home with me and now it does not show the
same error message and seem to be working which is probably pointing
to some sort of cabling problem. However, I also noticed that the DCE
connection does not have the positive power coming out anymore. This
is the cable that sends serial along with power to the PDA. I have
been doing some reading and it seems model 20 can supply about 500mA
of +5v. I am wondering if there is an internal fuse that is blown.
Paul Remde's site has a note about a "resettable fuse" (http://
www.cumulus-soaring.com/goddard.htm) but I can't find any other
references to it.


Cheers,
Morteza

[Paul Remde]

Hi Morteza,

The internal fuse resets itself when it cools down. Are you measuring the
+5 V for the PDA across pins 8 (+5V) and 5 (common)?

When you saw the error message, I'm assuming you saw that on the GPS-NAV LCD
Navigation Display - is that correct? If so, and since it seems to be
working better now, it could be (as Darryl suggested) a cable issue. Or the
GPS engine could be dead or dying. You may want to contact Gary Kammerer at
www.clearnav.net.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

"Morteza Ansari" > wrote in message
...
On Sep 25, 11:13 pm, Darryl Ramm > wrote:
> On 9/25/11 10:04 PM, Morteza Ansari wrote:
>
>
>
>
>
>
>
>
>
> > Hi,
>
> > I recently bought a glider and it has a GPS-NAV unit with a GPS20 in
> > it. It seemed to work fine when I bought it, but this weekend I
> > powered it up and it comes up with a "GPS Fail Press ON Key". When I
> > press the "ON" key, it just goes through the cycle again and comes
> > back to the same page.
>
> > It is running LCD version 5.3E, GPS version 6.0. The initial screens
> > all look good including the internal battery voltage (3.0v).
>
> > Any ideas or suggestions?
>
> > Cheers,
> > Morteza
>
> Almost certain to be cabling, corrosion, bent/abused pins in the telco
> connectors. Also RTFM for the Model 20 and make sure the LED on the
> Model 20 tells you it has a GPS signal/lock.
>
> Darryl

Thanks Darryl, I brought it home with me and now it does not show the
same error message and seem to be working which is probably pointing
to some sort of cabling problem. However, I also noticed that the DCE
connection does not have the positive power coming out anymore. This
is the cable that sends serial along with power to the PDA. I have
been doing some reading and it seems model 20 can supply about 500mA
of +5v. I am wondering if there is an internal fuse that is blown.
Paul Remde's site has a note about a "resettable fuse" (http://
www.cumulus-soaring.com/goddard.htm) but I can't find any other
references to it.


Cheers,
Morteza

[Morteza Ansari]

On Sep 26, 4:35*am, "Paul Remde" > wrote:
> Hi Morteza,
>
> The internal fuse resets itself when it cools down. *Are you measuring the
> +5 V for the PDA across pins 8 (+5V) and 5 (common)?
>
> When you saw the error message, I'm assuming you saw that on the GPS-NAV LCD
> Navigation Display - is that correct? *If so, and since it seems to be
> working better now, it could be (as Darryl suggested) a cable issue. *Or the
> GPS engine could be dead or dying. *You may want to contact Gary Kammerer atwww.clearnav.net.
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.
>
> "Morteza Ansari" > wrote in message
>
> ...
> On Sep 25, 11:13 pm, Darryl Ramm > wrote:
>
>
>
>
>
>
>
>
>
> > On 9/25/11 10:04 PM, Morteza Ansari wrote:
>
> > > Hi,
>
> > > I recently bought a glider and it has a GPS-NAV unit with a GPS20 in
> > > it. It seemed to work fine when I bought it, but this weekend I
> > > powered it up and it comes up with a "GPS Fail Press ON Key". When I
> > > press the "ON" key, it just goes through the cycle again and comes
> > > back to the same page.
>
> > > It is running LCD version 5.3E, GPS version 6.0. The initial screens
> > > all look good including the internal battery voltage (3.0v).
>
> > > Any ideas or suggestions?
>
> > > Cheers,
> > > Morteza
>
> > Almost certain to be cabling, corrosion, bent/abused pins in the telco
> > connectors. Also RTFM for the Model 20 and make sure the LED on the
> > Model 20 tells you it has a GPS signal/lock.
>
> > Darryl
>
> Thanks Darryl, I brought it home with me and now it does not show the
> same error message and seem to be working which is probably pointing
> to some sort of cabling problem. However, I also noticed that the DCE
> connection does not have the positive power coming out anymore. This
> is the cable that sends serial along with power to the PDA. *I have
> been doing some reading and it seems model 20 can supply about 500mA
> of +5v. I am wondering if there is an internal fuse that is blown.
> Paul Remde's site has a note about a "resettable fuse" (http://www.cumulus-soaring.com/goddard.htm) but I can't find any other
> references to it.
>
> Cheers,
> Morteza

Hi Paul,

Thanks for the reply. Yes, the error was on the GPS-NAV display. It
has been working on the bench at home and eve after quite a few power
cycles no error messages have come up. With that said, pin 8 is not
supplying the +5v, so the PDA is not working. I am wondering if the
"resettable fuse" you talked about on your web page is in need of
resetting!


Cheers,
Morteza

[Paul Remde]

Hi Morteza,

The fuse should not need resetting. It resets itself when it cools down.

If it isn't supplying 5V power then it must have been damaged and probably
needs repair. Please contact Gary Kammerer at www.clearnav.net.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

"Morteza Ansari" > wrote in message
...
On Sep 26, 4:35 am, "Paul Remde" > wrote:
> Hi Morteza,
>
> The internal fuse resets itself when it cools down. Are you measuring the
> +5 V for the PDA across pins 8 (+5V) and 5 (common)?
>
> When you saw the error message, I'm assuming you saw that on the GPS-NAV
> LCD
> Navigation Display - is that correct? If so, and since it seems to be
> working better now, it could be (as Darryl suggested) a cable issue. Or
> the
> GPS engine could be dead or dying. You may want to contact Gary Kammerer
> atwww.clearnav.net.
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.
>
> "Morteza Ansari" > wrote in message
>
> ...
> On Sep 25, 11:13 pm, Darryl Ramm > wrote:
>
>
>
>
>
>
>
>
>
> > On 9/25/11 10:04 PM, Morteza Ansari wrote:
>
> > > Hi,
>
> > > I recently bought a glider and it has a GPS-NAV unit with a GPS20 in
> > > it. It seemed to work fine when I bought it, but this weekend I
> > > powered it up and it comes up with a "GPS Fail Press ON Key". When I
> > > press the "ON" key, it just goes through the cycle again and comes
> > > back to the same page.
>
> > > It is running LCD version 5.3E, GPS version 6.0. The initial screens
> > > all look good including the internal battery voltage (3.0v).
>
> > > Any ideas or suggestions?
>
> > > Cheers,
> > > Morteza
>
> > Almost certain to be cabling, corrosion, bent/abused pins in the telco
> > connectors. Also RTFM for the Model 20 and make sure the LED on the
> > Model 20 tells you it has a GPS signal/lock.
>
> > Darryl
>
> Thanks Darryl, I brought it home with me and now it does not show the
> same error message and seem to be working which is probably pointing
> to some sort of cabling problem. However, I also noticed that the DCE
> connection does not have the positive power coming out anymore. This
> is the cable that sends serial along with power to the PDA. I have
> been doing some reading and it seems model 20 can supply about 500mA
> of +5v. I am wondering if there is an internal fuse that is blown.
> Paul Remde's site has a note about a "resettable fuse"
> (http://www.cumulus-soaring.com/goddard.htm) but I can't find any other
> references to it.
>
> Cheers,
> Morteza

Hi Paul,

Thanks for the reply. Yes, the error was on the GPS-NAV display. It
has been working on the bench at home and eve after quite a few power
cycles no error messages have come up. With that said, pin 8 is not
supplying the +5v, so the PDA is not working. I am wondering if the
"resettable fuse" you talked about on your web page is in need of
resetting!


Cheers,
Morteza

[Morteza Ansari]

On Sep 26, 5:02*pm, "Paul Remde" > wrote:
> Hi Morteza,
>
> The fuse should not need resetting. *It resets itself when it cools down.

[PMSC Member]

Here's the history of that "GPS Fail - Press ON" message.

The Display and the Flight Recorder are two separate microcomputers
running two separate programs on two separate processors. They
communicate with each other using an asynchronous protocol. If, for
any reason, communications cannot be established, the Display gives up
and displays that message. In the early days, the protocol was
experimental, and some unrecoverable errors occurred. Pressing ON
restarts the Display microprocessor, and that took care of the
problem. Later, the protocol became more robust, and it is very
unlikely that a communication failure today is a failure of the
logic. It is FAR more likely that the fault is an open circuit
(broken wire or connector), and in this case, pressing ON does not
solve the problem. A better message would be: "Communication failure
between Display and FR. Check cable."

[Darryl Ramm]

On 9/27/11 12:13 AM, Morteza Ansari wrote:
[snip]

> However I am still puzzled as to why I got the
> error. Based on Gary (which BTW was a great help and very responsive
> in his support; thanks Gary) this is an internal Garmin Receiver
> error. No idea why I got it on the weekend.

It is unlikely an error in the Garmin GPS receiver module. It is very
likely to be just exactly what I mentioned earlier. A cabling or
connector problem. Look at them all carefully and wiggle them and see if
you can reproduce this.

Darryl

[Paul Remde]

Hi,

If you are good with RJ connectors, then replace the connectors on both ends
of the cable that connects the GPS-NAV to the navigation display. If not, I
can sell a ready-to-use new cable to you for $30.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

"Darryl Ramm" > wrote in message
...
> On 9/27/11 12:13 AM, Morteza Ansari wrote:
> [snip]
>
>> However I am still puzzled as to why I got the
>> error. Based on Gary (which BTW was a great help and very responsive
>> in his support; thanks Gary) this is an internal Garmin Receiver
>> error. No idea why I got it on the weekend.
>
> It is unlikely an error in the Garmin GPS receiver module. It is very
> likely to be just exactly what I mentioned earlier. A cabling or connector
> problem. Look at them all carefully and wiggle them and see if you can
> reproduce this.
>
> Darryl
>

[Morteza Ansari]

On Sep 27, 9:15*am, PMSC Member > wrote:
> Here's the history of that "GPS Fail - Press ON" message.
>
> The Display and the Flight Recorder are two separate microcomputers
> running two separate programs on two separate processors. *They
> communicate with each other using an asynchronous protocol. *If, for
> any reason, communications cannot be established, the Display gives up
> and displays that message. *In the early days, the protocol was
> experimental, and some unrecoverable errors occurred. *Pressing ON
> restarts the Display microprocessor, and that took care of the
> problem. *Later, the protocol became more robust, and it is very
> unlikely that a communication failure today is a failure of the
> logic. *It is FAR more likely that the fault is an open circuit
> (broken wire or connector), and in this case, pressing ON does not
> solve the problem. *A better message would be: "Communication failure
> between Display and FR. *Check cable."

Thanks for the explanation. This is actually very helpful in
understanding the problem. I am making new cables all around.
Hopefully I won't see this anymore.

[Morteza Ansari]

On Sep 27, 4:13*pm, "Paul Remde" > wrote:
> Hi,
>
> If you are good with RJ connectors, then replace the connectors on both ends
> of the cable that connects the GPS-NAV to the navigation display. *If not, I
> can sell a ready-to-use new cable to you for $30.
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.
>
> "Darryl Ramm" > wrote in message
>
> ...
>
>
>
>
>
>
>
> > On 9/27/11 12:13 AM, Morteza Ansari wrote:
> > [snip]
>
> >> However I am still puzzled as to why I got the
> >> error. *Based on Gary (which BTW was a great help and very responsive
> >> in his support; thanks Gary) this is an internal Garmin Receiver
> >> error. *No idea why I got it on the weekend.
>
> > It is unlikely an error in the Garmin GPS receiver module. It is very
> > likely to be just exactly what I mentioned earlier. A cabling or connector
> > problem. Look at them all carefully and wiggle them and see if you can
> > reproduce this.
>
> > Darryl

Thanks Paul & Darryl, I do have the connectors and tool to build new
cables and I already have new cables for all connections and cleaned
up the female connectors on the device. Will give it a try and see if
the problem comes back. On the bench everything is working.


Cheers,
Morteza

[[email protected]]

I'm seeing this myself now. I'll check the cables thoroughly and perhaps make new ones. Thanks for posting Morteza.