Buck converter vs power from Pi question... #12vsupply


Jack Spitznagel
 

John, Bryan, and Basil,

 

Take a look at the close up in https://nw-digital-radio.groups.io/g/udrc/message/5393. In that set up am not using 12V through the DRAWS buck converter, rather powering the whole beast from the Pi4 USB 3. I am still a bit nervous after my experience with one of the early experience boards where the buck converter and the GPS chip got very hot and apparently one or both failed. Happy to send the hat back for a post-mortem (on my dime) if you think it would be helpful to have a failure analysis. Frankly I would love to fix it if I can identify the bad chips, but not exactly sure where to start looking to analyze...

 

Jack Spitznagel – KD4IZ

Science River LLC

Biomedical Consulting Services


--
Jack - KD4IZ


Basil Gunn
 

Hey Jack,

Bryan should comment on this:
after my experience with one of the early experience boards where the
buck converter and the GPS chip got very hot and apparently one or
both failed. Happy to send the hat back for a post-mortem
I have been running multiple different versions of DRAWS boards on 12V
supplies for over a year & I have not seen your symptom. However, I have
a friend who has seen 2 of his RPi/DRAWS units experience much elevated
temperatures. I actually fixed one of his units by updating his kernel &
swapping out one of the heat sinks.

1. I power my RPi/DRAWS units with Alinco DM-330MV power supplies set to
13.8V except for the one I run in my truck.

2. All heat sinks for the RPi are not equal. My experience is that the
super cheap ones (they are all pretty cheap) have inferior thermally
conductive paste.

3. If you have an RPi 4 be sure to run the latest Raspberry Pi OS
package update as that also contains current firmware for the RPi. If
you are seeing temperatures > 80C then you need to update your RPi
firmware.

4. If you are interested in tracking your temperature, graph it out. I
have a repository that plots RPi core temp, ambient temp & CPU activity:

https://github.com/n7nix/rpi-temp-graph

Other:
I supply a script on the NWDR image that displays current RPi core temp
& throttled state. The following script was run on:
Pi 4 Model B, Rev 1.1, 4GB mem with NO fan.

pi_throt.sh

temp=53.5'C
throttled=0x0

kd4iz de n7nix

Jack Spitznagel <kd4iz@frawg.org> writes:

John, Bryan, and Basil,

Take a look at the close up in
https://nw-digital-radio.groups.io/g/udrc/message/5393. In that set up
am not using 12V through the DRAWS buck converter, rather powering the
whole beast from the Pi4 USB 3. I am still a bit nervous after my
experience with one of the early experience boards where the buck
converter and the GPS chip got very hot and apparently one or both
failed. Happy to send the hat back for a post-mortem (on my dime) if
you think it would be helpful to have a failure analysis. Frankly I
would love to fix it if I can identify the bad chips, but not exactly
sure where to start looking to analyze...

Jack Spitznagel – KD4IZ

Science River LLC

Biomedical Consulting Services


 

Hey Jack,

We have had zero failures in the Buck Converter, except for unfused reverse voltage blowing the protection diode. If you power the Pi separately we use the recommended isolation circuit. In fact, I have hot switched between the 2 supplies without problems.

All ICs  on DRAWS, including the GPS, operate on the 3.3V supply, which is provided by the Pi. We have had zero GPS failures, we did have an I2C to serial failure on 1 unit. The GPS receiver is on the I2C serial port.

Email me at sales@... and I’ll arrange for a refurb unit for you.

73,
Bryan K7UDR

On Jan 24, 2021, at 11:56 AM, Basil Gunn <basil@...> wrote:


Hey Jack,

Bryan should comment on this:
after my experience with one of the early experience boards where the
buck converter and the GPS chip got very hot and apparently one or
both failed. Happy to send the hat back for a post-mortem

I have been running multiple different versions of DRAWS boards on 12V
supplies for over a year & I have not seen your symptom. However, I have
a friend who has seen 2 of his RPi/DRAWS units experience much elevated
temperatures. I actually fixed one of his units by updating his kernel &
swapping out one of the heat sinks.

1. I power my RPi/DRAWS units with Alinco DM-330MV power supplies set to
13.8V except for the one I run in my truck.

2. All heat sinks for the RPi are not equal. My experience is that the
super cheap ones (they are all pretty cheap) have inferior thermally
conductive paste.

3. If you have an RPi 4 be sure to run the latest Raspberry Pi OS
package update as that also contains current firmware for the RPi. If
you are seeing temperatures > 80C then you need to update your RPi
firmware.

4. If you are interested in tracking your temperature, graph it out. I
have a repository that plots RPi core temp, ambient temp & CPU activity:

https://github.com/n7nix/rpi-temp-graph

Other:
I supply a script on the NWDR image that displays current RPi core temp
& throttled state. The following script was run on: 
Pi 4 Model B, Rev 1.1, 4GB mem with NO fan.

pi_throt.sh

temp=53.5'C
throttled=0x0

kd4iz de n7nix

Jack Spitznagel <kd4iz@...> writes:

John, Bryan, and Basil,

Take a look at the close up in
https://nw-digital-radio.groups.io/g/udrc/message/5393. In that set up
am not using 12V through the DRAWS buck converter, rather powering the
whole beast from the Pi4 USB 3. I am still a bit nervous after my
experience with one of the early experience boards where the buck
converter and the GPS chip got very hot and apparently one or both
failed. Happy to send the hat back for a post-mortem (on my dime) if
you think it would be helpful to have a failure analysis. Frankly I
would love to fix it if I can identify the bad chips, but not exactly
sure where to start looking to analyze...

Jack Spitznagel – KD4IZ

Science River LLC

Biomedical Consulting Services




Jack Spitznagel
 

Hi Bryan,

 

Thanks… but this board is the “hulk” of a board you replaced back a while after the problem occurred. The GPS chip and chips around it got very hot after a cat had knocked the GPS puck off the window casing ledge. I noticed after it was too late that the puck rattles – perhaps something got knocked loose. I bought a replacement puck from you, which did not stop the issue.

 

I pulled the original Pi3B and the old board out the other day and found that the pi will boot (no hat), but will eventually become heat unstable. It would boot (hat on) while powered from the pi, but not when powered from the DRAWS hat. When it booted (with a configured SD card), the GPS is “unreachable” with the new puck attached. (Puck works on another unit.) That section of the board around the GPS chip warms up again, but not like it did for the failure.

 

I’ll be happy to send in the board and if we can figure out whether a refurb is possible, you are welcome to return it to service and resell if you think it is worth the trouble. I have two working systems now so I really don’t know what I would do with a third.

 

Jack Spitznagel – KD4IZ

Cell: (410) 207-5123

Biomedical Consulting Services

 

 

 

From: udrc@nw-digital-radio.groups.io <udrc@nw-digital-radio.groups.io> On Behalf Of Bryan Hoyer
Sent: Sunday, January 31, 2021 19:34
To: udrc@nw-digital-radio.groups.io
Subject: Re: [draws and udrc] Buck converter vs power from Pi question... #12vsupply

 

Hey Jack,

 

We have had zero failures in the Buck Converter, except for unfused reverse voltage blowing the protection diode. If you power the Pi separately we use the recommended isolation circuit. In fact, I have hot switched between the 2 supplies without problems.

 

All ICs  on DRAWS, including the GPS, operate on the 3.3V supply, which is provided by the Pi. We have had zero GPS failures, we did have an I2C to serial failure on 1 unit. The GPS receiver is on the I2C serial port.

 

Email me at sales@... and I’ll arrange for a refurb unit for you.

 

73,

Bryan K7UDR



On Jan 24, 2021, at 11:56 AM, Basil Gunn <basil@...> wrote:

 


Hey Jack,

Bryan should comment on this:

after my experience with one of the early experience boards where the
buck converter and the GPS chip got very hot and apparently one or
both failed. Happy to send the hat back for a post-mortem


I have been running multiple different versions of DRAWS boards on 12V
supplies for over a year & I have not seen your symptom. However, I have
a friend who has seen 2 of his RPi/DRAWS units experience much elevated
temperatures. I actually fixed one of his units by updating his kernel &
swapping out one of the heat sinks.

1. I power my RPi/DRAWS units with Alinco DM-330MV power supplies set to
13.8V except for the one I run in my truck.

2. All heat sinks for the RPi are not equal. My experience is that the
super cheap ones (they are all pretty cheap) have inferior thermally
conductive paste.

3. If you have an RPi 4 be sure to run the latest Raspberry Pi OS
package update as that also contains current firmware for the RPi. If
you are seeing temperatures > 80C then you need to update your RPi
firmware.

4. If you are interested in tracking your temperature, graph it out. I
have a repository that plots RPi core temp, ambient temp & CPU activity:

https://github.com/n7nix/rpi-temp-graph

Other:
I supply a script on the NWDR image that displays current RPi core temp
& throttled state. The following script was run on: 
Pi 4 Model B, Rev 1.1, 4GB mem with NO fan.

pi_throt.sh

temp=53.5'C
throttled=0x0

kd4iz de n7nix

Jack Spitznagel <
kd4iz@...> writes:


John, Bryan, and Basil,

Take a look at the close up in
https://nw-digital-radio.groups.io/g/udrc/message/5393. In that set up
am not using 12V through the DRAWS buck converter, rather powering the
whole beast from the Pi4 USB 3. I am still a bit nervous after my
experience with one of the early experience boards where the buck
converter and the GPS chip got very hot and apparently one or both
failed. Happy to send the hat back for a post-mortem (on my dime) if
you think it would be helpful to have a failure analysis. Frankly I
would love to fix it if I can identify the bad chips, but not exactly
sure where to start looking to analyze...

Jack Spitznagel – KD4IZ

Science River LLC

Biomedical Consulting Services




 


 

OK Jack,

“Death by Kitty”

We don’t resell refurbs, I just keep a few as replacements or Developer give-a-ways.

Just toss it, and if you need anything else let me know.

73,
Bryan K7UDR

On Jan 31, 2021, at 7:16 PM, Jack Spitznagel <kd4iz@...> wrote:

Hi Bryan,
 
Thanks… but this board is the “hulk” of a board you replaced back a while after the problem occurred. The GPS chip and chips around it got very hot after a cat had knocked the GPS puck off the window casing ledge. I noticed after it was too late that the puck rattles – perhaps something got knocked loose. I bought a replacement puck from you, which did not stop the issue. 
 
I pulled the original Pi3B and the old board out the other day and found that the pi will boot (no hat), but will eventually become heat unstable. It would boot (hat on) while powered from the pi, but not when powered from the DRAWS hat. When it booted (with a configured SD card), the GPS is “unreachable” with the new puck attached. (Puck works on another unit.) That section of the board around the GPS chip warms up again, but not like it did for the failure.
 
I’ll be happy to send in the board and if we can figure out whether a refurb is possible, you are welcome to return it to service and resell if you think it is worth the trouble. I have two working systems now so I really don’t know what I would do with a third.
 
Jack Spitznagel – KD4IZ
Cell: (410) 207-5123
<image002.jpg>
Biomedical Consulting Services
 
 
 
From: udrc@nw-digital-radio.groups.io <udrc@nw-digital-radio.groups.io> On Behalf Of Bryan Hoyer
Sent: Sunday, January 31, 2021 19:34
To: udrc@nw-digital-radio.groups.io
Subject: Re: [draws and udrc] Buck converter vs power from Pi question... #12vsupply
 
Hey Jack,
 
We have had zero failures in the Buck Converter, except for unfused reverse voltage blowing the protection diode. If you power the Pi separately we use the recommended isolation circuit. In fact, I have hot switched between the 2 supplies without problems.
 
All ICs  on DRAWS, including the GPS, operate on the 3.3V supply, which is provided by the Pi. We have had zero GPS failures, we did have an I2C to serial failure on 1 unit. The GPS receiver is on the I2C serial port.
 
Email me at sales@... and I’ll arrange for a refurb unit for you.
 
73,
Bryan K7UDR


On Jan 24, 2021, at 11:56 AM, Basil Gunn <basil@...> wrote:
 

Hey Jack,

Bryan should comment on this:

after my experience with one of the early experience boards where the
buck converter and the GPS chip got very hot and apparently one or
both failed. Happy to send the hat back for a post-mortem

I have been running multiple different versions of DRAWS boards on 12V
supplies for over a year & I have not seen your symptom. However, I have
a friend who has seen 2 of his RPi/DRAWS units experience much elevated
temperatures. I actually fixed one of his units by updating his kernel &
swapping out one of the heat sinks.

1. I power my RPi/DRAWS units with Alinco DM-330MV power supplies set to
13.8V except for the one I run in my truck.

2. All heat sinks for the RPi are not equal. My experience is that the
super cheap ones (they are all pretty cheap) have inferior thermally
conductive paste.

3. If you have an RPi 4 be sure to run the latest Raspberry Pi OS
package update as that also contains current firmware for the RPi. If
you are seeing temperatures > 80C then you need to update your RPi
firmware.

4. If you are interested in tracking your temperature, graph it out. I
have a repository that plots RPi core temp, ambient temp & CPU activity:

https://github.com/n7nix/rpi-temp-graph

Other:
I supply a script on the NWDR image that displays current RPi core temp
& throttled state. The following script was run on: 
Pi 4 Model B, Rev 1.1, 4GB mem with NO fan.

pi_throt.sh

temp=53.5'C
throttled=0x0

kd4iz de n7nix

Jack Spitznagel <
kd4iz@...> writes:


John, Bryan, and Basil,

Take a look at the close up in
https://nw-digital-radio.groups.io/g/udrc/message/5393. In that set up
am not using 12V through the DRAWS buck converter, rather powering the
whole beast from the Pi4 USB 3. I am still a bit nervous after my
experience with one of the early experience boards where the buck
converter and the GPS chip got very hot and apparently one or both
failed. Happy to send the hat back for a post-mortem (on my dime) if
you think it would be helpful to have a failure analysis. Frankly I
would love to fix it if I can identify the bad chips, but not exactly
sure where to start looking to analyze...

Jack Spitznagel – KD4IZ

Science River LLC

Biomedical Consulting Services



 



Jack Spitznagel
 

Bryan,

Sounds good…

“Death by Kitty” with a basso profundo voice (think James Earl Jones as Darth). When one has a 22lb Maine Coon Cat who is a pro at shelf surfing, one need not do stupid things like leaving fragile objects on window sills and bookshelf shelves. Shame on me.

Anyway, I need some SMC soldering practice…. 😊 Maybe I can troubleshoot…

-Jack

 

From: udrc@nw-digital-radio.groups.io <udrc@nw-digital-radio.groups.io> On Behalf Of Bryan Hoyer
Sent: Monday, February 1, 2021 09:27
To: udrc@nw-digital-radio.groups.io
Subject: Re: [draws and udrc] Buck converter vs power from Pi question... #12vsupply

 

OK Jack,

 

“Death by Kitty”

 

We don’t resell refurbs, I just keep a few as replacements or Developer give-a-ways.

 

Just toss it, and if you need anything else let me know.

 

73,

Bryan K7UDR



On Jan 31, 2021, at 7:16 PM, Jack Spitznagel <kd4iz@...> wrote:

 

Hi Bryan,

 

Thanks… but this board is the “hulk” of a board you replaced back a while after the problem occurred. The GPS chip and chips around it got very hot after a cat had knocked the GPS puck off the window casing ledge. I noticed after it was too late that the puck rattles – perhaps something got knocked loose. I bought a replacement puck from you, which did not stop the issue. 

 

I pulled the original Pi3B and the old board out the other day and found that the pi will boot (no hat), but will eventually become heat unstable. It would boot (hat on) while powered from the pi, but not when powered from the DRAWS hat. When it booted (with a configured SD card), the GPS is “unreachable” with the new puck attached. (Puck works on another unit.) That section of the board around the GPS chip warms up again, but not like it did for the failure.

 

I’ll be happy to send in the board and if we can figure out whether a refurb is possible, you are welcome to return it to service and resell if you think it is worth the trouble. I have two working systems now so I really don’t know what I would do with a third.

 

Jack Spitznagel – KD4IZ

Cell: (410) 207-5123

<image002.jpg>

Biomedical Consulting Services

 

 

 

From: udrc@nw-digital-radio.groups.io <udrc@nw-digital-radio.groups.io> On Behalf Of Bryan Hoyer
Sent: Sunday, January 31, 2021 19:34
To: udrc@nw-digital-radio.groups.io
Subject: Re: [draws and udrc] Buck converter vs power from Pi question... #12vsupply

 

Hey Jack,

 

We have had zero failures in the Buck Converter, except for unfused reverse voltage blowing the protection diode. If you power the Pi separately we use the recommended isolation circuit. In fact, I have hot switched between the 2 supplies without problems.

 

All ICs  on DRAWS, including the GPS, operate on the 3.3V supply, which is provided by the Pi. We have had zero GPS failures, we did have an I2C to serial failure on 1 unit. The GPS receiver is on the I2C serial port.

 

Email me at sales@... and I’ll arrange for a refurb unit for you.

 

73,

Bryan K7UDR




On Jan 24, 2021, at 11:56 AM, Basil Gunn <basil@...> wrote:

 


Hey Jack,

Bryan should comment on this:


after my experience with one of the early experience boards where the
buck converter and the GPS chip got very hot and apparently one or
both failed. Happy to send the hat back for a post-mortem


I have been running multiple different versions of DRAWS boards on 12V
supplies for over a year & I have not seen your symptom. However, I have
a friend who has seen 2 of his RPi/DRAWS units experience much elevated
temperatures. I actually fixed one of his units by updating his kernel &
swapping out one of the heat sinks.

1. I power my RPi/DRAWS units with Alinco DM-330MV power supplies set to
13.8V except for the one I run in my truck.

2. All heat sinks for the RPi are not equal. My experience is that the
super cheap ones (they are all pretty cheap) have inferior thermally
conductive paste.

3. If you have an RPi 4 be sure to run the latest Raspberry Pi OS
package update as that also contains current firmware for the RPi. If
you are seeing temperatures > 80C then you need to update your RPi
firmware.

4. If you are interested in tracking your temperature, graph it out. I
have a repository that plots RPi core temp, ambient temp & CPU activity:

https://github.com/n7nix/rpi-temp-graph

Other:
I supply a script on the NWDR image that displays current RPi core temp
& throttled state. The following script was run on: 
Pi 4 Model B, Rev 1.1, 4GB mem with NO fan.

pi_throt.sh

temp=53.5'C
throttled=0x0

kd4iz de n7nix

Jack Spitznagel <
kd4iz@...> writes:



John, Bryan, and Basil,

Take a look at the close up in
https://nw-digital-radio.groups.io/g/udrc/message/5393. In that set up
am not using 12V through the DRAWS buck converter, rather powering the
whole beast from the Pi4 USB 3. I am still a bit nervous after my
experience with one of the early experience boards where the buck
converter and the GPS chip got very hot and apparently one or both
failed. Happy to send the hat back for a post-mortem (on my dime) if
you think it would be helpful to have a failure analysis. Frankly I
would love to fix it if I can identify the bad chips, but not exactly
sure where to start looking to analyze...

Jack Spitznagel – KD4IZ

Science River LLC

Biomedical Consulting Services





 

 


kc7pmu
 

You might try a steel pie plate or cookie sheet attached to the shelf with means and methods appropriate to the size of the sweet puddy tat. The magnet should keep the GPS puck anchored sufficiently for occasional excursion by the perp.

I find the method sufficient for my 2m mag mount antenna and the GPS puck.

Good luck.

Paul
kc7pmu


Jack Spitznagel
 

“Appropriate Attachment” for “Breg the beast” would be 1/4” carriage bolts with oversize washers. My safest approach would be to fasten a piece of angled galvanized sheet metal outside a window near the op station with a plastic container placed over the puck. 🙂

Jack - KD4IZ 

On Feb 1, 2021, at 22:29, kc7pmu <kc7pmu@...> wrote:

You might try a steel pie plate or cookie sheet attached to the shelf with means and methods appropriate to the size of the sweet puddy tat. The magnet should keep the GPS puck anchored sufficiently for occasional excursion by the perp.

I find the method sufficient for my 2m mag mount antenna and the GPS puck.

Good luck.

Paul
kc7pmu