Qgl1 gps question


Art Olson
 

Built the gps module and plugged it into a rpi. Red and yellow leds are on but the yellow doesn’t flash and after an hour the the green never lit.  Where to start troubleshooting. Do I need something loaded on the rpi? 


art
N2AJO


N3MNT
 

Does it have a good visibility to the Sky?  Try powering it with nothing connect except pwr and Gnd. 


Eike Lantzsch
 

On Friday, 5 February 2021 21:08:27 -03 Art Olson wrote:
Built the gps module and plugged it into a rpi. Red and yellow leds
are on but the yellow doesn’t flash and after an hour the the green
never lit. Where to start troubleshooting. Do I need something
loaded on the rpi?

art
N2AJO
Hi Art,
the yellow light must not be constantly on. It is supposed to be flashing
to indicate that data is sent via TXD on the two interfaces.
Is there a clock pulse on pin 1,2 of IC1a both sides of R2?
Are there data pulses on pin 9,10 of IC1c - both sides of R1?
That can be observed (if any) even with a DVM if you don't happen to
have an oscilloscope.
If you don't detect any pulses the RF module is not receiving any data
from the satellites.
But because the yellow light is constantly on I suspect a solder bridge
or bad contact on IC1 somewhere. Is the ground connection OK?
Is 3.3V present between pin 23 and pin 10,12,13,24 of the RF module?
Is 3V of the Li battery present on pin 22 of the RF module?

Keep us posted and we can check further.

vy 73
Eike ZP6CGE


Eike Lantzsch
 

On Friday, 5 February 2021 21:08:27 -03 Art Olson wrote:
Built the gps module and plugged it into a rpi. Red and yellow leds
are on but the yellow doesn’t flash and after an hour the the green
never lit. Where to start troubleshooting. Do I need something
loaded on the rpi?

art
N2AJO
Yellow LED constantly on and green LED not flashing indicates constant
low output of IC1.


Mont Pierce KM6WT
 

I don't have anything additional to help troubleshoot.

But on this point:

On Fri, Feb 5, 2021 at 04:08 PM, Art Olson wrote:
Do I need something loaded on the rpi? 

No.   The QLG1 GPS Receiver can run all on it's own with just power and ground.

I often run mine like that for minutes/hours before I need to use it to calibrate one of my other QRP-Lab kits.

But, I've never seen the Yellow LED not Blinking...


73
km6wt




Jesus Christ on Toast
 

On Fri, Feb 5, 2021 at 04:08 PM, Art Olson wrote:
Built the gps module and plugged it into a rpi. Red and yellow leds are on but the yellow doesn’t flash and after an hour the the green never lit.  Where to start troubleshooting. Do I need something loaded on the rpi? 
Not sure what you're trying to achieve here with a Pi.

Are you atempting to use a QLG1 as a time source for a Pi ?

As I understand it, you need to install gpsd - in the terminal type "sudo apt-get install gpsd" and then read the docs
on what command line you need to run it.

It's something that I keep meaning to expriment with too at some point.

I understand that a GPS module can be interfaced to the Pi using the GPIO bus at 3.3v levels or USB.

That's all I can offer at this time, since I have plenty of Pi's, but no spare GPS modules set up to experiment further.


Art Olson
 

Eike

Think I have located the problem - no 3.3v on the pin 2 of IC2. When powered up IC2 run hot to the touch.  There is 5.1 v on pin 3 (vin). Verified R7 and R6 are correct values. I have looked for a pinout diagram for the Rf module but could not locate one so don't know the pin numbering on the module. But would seem without any 3.3v from IC2 it wont work. there is 3.3v when powered off on, I assume pin 22 of the RF module

Art
N2AJO


Roger Hill
 

Hi Art.


So it sounds as though you have a faulty IC2 (unlikely), or a short to ground on the output side (pin 2).


You can check the short by removing power from the unit, and with your meter on 'Ohms', check from pin2 to ground...it should be a very high value. A low value will cause the symptoms you are seeing.


Possibly C4 is in backwards.

Roger

8P6RX

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***************************
Roger Hill
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On 2021-02-06 10:51, Art Olson wrote:

Eike

Think I have located the problem - no 3.3v on the pin 2 of IC2. When powered up IC2 run hot to the touch.  There is 5.1 v on pin 3 (vin). Verified R7 and R6 are correct values. I have looked for a pinout diagram for the Rf module but could not locate one so don't know the pin numbering on the module. But would seem without any 3.3v from IC2 it wont work. there is 3.3v when powered off on, I assume pin 22 of the RF module

Art
N2AJO


Art Olson
 

Roger

Yes pin 2 is shorted to ground. Removed IC2 and checked pin 2 - still shorted. Removed C4, C5, C2 and R7 - still shorted to ground. Only connection left is to pin 23 of Rf module which seems it is shorted to ground also. Maybe time for a now gps module


Roger Hill
 

Hi Art.
That does not sound good. But you might want to inspect the area around pin 2 of IC2 to pin 23 of the RF module for solder blobs, whiskers etc. Maybe even under the RF module.


If nothing found, I agree that a new RF module sounds like it is necessary.

Roger
8P6RX

On 6 Feb 2021, at 11:09, Roger Hill <rhill@...> wrote:

Hi Art.


So it sounds as though you have a faulty IC2 (unlikely), or a short to ground on the output side (pin 2).


You can check the short by removing power from the unit, and with your meter on 'Ohms', check from pin2 to ground...it should be a very high value. A low value will cause the symptoms you are seeing.


Possibly C4 is in backwards.

Roger

8P6RX

---
***************************
Roger Hill
***************************


On 2021-02-06 10:51, Art Olson wrote:

Eike

Think I have located the problem - no 3.3v on the pin 2 of IC2. When powered up IC2 run hot to the touch.  There is 5.1 v on pin 3 (vin). Verified R7 and R6 are correct values. I have looked for a pinout diagram for the Rf module but could not locate one so don't know the pin numbering on the module. But would seem without any 3.3v from IC2 it wont work. there is 3.3v when powered off on, I assume pin 22 of the RF module

Art
N2AJO