Topics

uBITX V6 heat sink temperature

 

Hi all,

I have my V6 all hooked up and calibrated and have checked into a few nets with my own home brew mic, the supplied one got bad reports, however I have noticed that the 5 volt regulator heat sink is running at 142 degrees F or 61.1 C. That seems hot to me. Anyone else?

Joel
N6ALT

Ashhar Farhan
 

I hope the heatsink is clipped on. I have been running the radio continuously for a month now. No harm done.
In an earlier version, I was using a switching regulator. It was horribly noisy. I just took the lazy way out.

- f


On Fri 27 Dec, 2019, 10:41 PM Joel Caulkins/N6ALT, <caulktel@...> wrote:
Hi all,

I have my V6 all hooked up and calibrated and have checked into a few nets with my own home brew mic, the supplied one got bad reports, however I have noticed that the 5 volt regulator heat sink is running at 142 degrees F or 61.1 C. That seems hot to me. Anyone else?

Joel
N6ALT

 

Mine is at 114 F

Bit hot.
--
David

 N8DAH
Kit-Projects.com

Shop is open!

 

It has the heat sink screwed on and is tight, the fact that the heat sink is so hot means it's working, it's transferring the heat. Maybe I'll change the regulator to a new one to and see if it runs any cooler.

Joel
N6ALT

iz oos
 

60C degrees don't seem to me really too hot but actually I have no much experience with finals. The CPU temperature of my laptop is about 75C degrees.


Il 27/dic/2019 20:20, "Joel Caulkins/N6ALT" <caulktel@...> ha scritto:
It has the heat sink screwed on and is tight, the fact that the heat sink is so hot means it's working, it's transferring the heat. Maybe I'll change the regulator to a new one to and see if it runs any cooler.

Joel
N6ALT

 

I have replaced the 5 volt regulator and now the temp is running at 136 degrees F, only 6 degrees less. Still too hot. Next I will program one of my own Nano's and swap it out to see if maybe this one is drawing too much current.

Joel
N6ALT

Lev <leventelist@...>
 

Can you measure the current? Can you upgrade your heatsink?


On Mon, Dec 30, 2019, 00:40 Joel Caulkins/N6ALT <caulktel@...> wrote:
I have replaced the 5 volt regulator and now the temp is running at 136 degrees F, only 6 degrees less. Still too hot. Next I will program one of my own Nano's and swap it out to see if maybe this one is drawing too much current.

Joel
N6ALT

Evan Hand
 

Joel,
I do not have a v6 uBitx, so do not have direct experience with that specific kit.  I do have both v4 and v5 boards, and all do run the regulator hot, especially if I use a 13.8 volt "big rig" power supply.  What I did to tame the temperature was to add a dropping resistor on the 12vdc (actually 13.8) in series with the regulator.  two 2 ohm 2 watt resistors in series.  This drops the voltage across the resistor so that the regulator does not have to disipate the heat.  This value can be up to about 47 Ohms depending on how much current you are planing to use for add on things.

Others have added a 7809 9vdc regulator in place of the resistor.  This spreads the load across the two devices and works well if the input voltage is always above 12vdc.  You would need to go to a buck/boost regulator if you are going to power from battery power if you want to rung the batteries to almost fully drained.

Most v3, v4 and v5 boards have been running with the stock circuit and no heatsink.  Adding the graphics display increased the current need, which is why I believe that HF Signals added the heatsink.

Bottom line of the above is that the heat dissipation at 12 votls is within the spec of the device, and I would not be worried.   If you are running over 12vdc in, then putting dropping diodes in series with the supply to the main board, NOT the power amp, would be my suggestion.  The finals can take the higher voltage and produce more power out, at the risk of overheating the finals.

Above should be verified before implementation
73
Evan
AC9TU

Alex Netherton
 

Wow, when I have my SB-200 just turned on, it heats the room. When I in a long QSO, I have to open the window!

Warm finals are just a fact of life.If you are running Class B, your duty cycle is 50%, meaning that you are feeding the transistors with 20 to 25 watts, dissipating around 10 watts (or so). This will indeed heat up the heat sink, but most JFETS are rated for such temperatures. If the transistors are biased for Class AB, then you are likely putting close to 30 watts in to get 10 out.

Just put a hot dog on top of the finals!


On Fri, Dec 27, 2019 at 12:11 PM Joel Caulkins/N6ALT <caulktel@...> wrote:
Hi all,

I have my V6 all hooked up and calibrated and have checked into a few nets with my own home brew mic, the supplied one got bad reports, however I have noticed that the 5 volt regulator heat sink is running at 142 degrees F or 61.1 C. That seems hot to me. Anyone else?

Joel
N6ALT

Jerry Gaffke
 

I believe Joel is talking about the LM7805 regulator on the Raduino.
The LM7805 is spec'd to continue working at temps as high as 150 C.

I have no idea how hot it should get on a v6 with the new display, but on the older uBitx's
the Raduino typically drew around 60ma from the 12v supply.
So about (12-5)*0.060) = 0.42 Watts dissipated as heat in the LM7805.
They figure the part rises about 19 degrees C per watt to be dissipated above the ambient air,
so 60 C does seem kind of high.  But it's not about to burn up.

Would be interesting to hear reports about how much current the Raduino on a v6 draws.

Some of the Nano's on the Raduino have been found to draw more current than others.
Some uBitx owners felt the LM7805 was way too hot, and put a heatsink on it.
The Raduino should get just as hot during receive as during transmit.

Jerry, KE7ER


On Mon, Dec 30, 2019 at 04:26 PM, Alex Netherton wrote:
Wow, when I have my SB-200 just turned on, it heats the room. When I in a long QSO, I have to open the window!

Warm finals are just a fact of life.If you are running Class B, your duty cycle is 50%, meaning that you are feeding the transistors with 20 to 25 watts, dissipating around 10 watts (or so). This will indeed heat up the heat sink, but most JFETS are rated for such temperatures. If the transistors are biased for Class AB, then you are likely putting close to 30 watts in to get 10 out.
 
Just put a hot dog on top of the finals!
Hide quoted text

 


On Fri, Dec 27, 2019 at 12:11 PM Joel Caulkins/N6ALT <caulktel@...> wrote:
Hi all,

I have my V6 all hooked up and calibrated and have checked into a few nets with my own home brew mic, the supplied one got bad reports, however I have noticed that the 5 volt regulator heat sink is running at 142 degrees F or 61.1 C. That seems hot to me. Anyone else?

Joel
N6ALT

bill richardson
 

My V6 at the power plug is seeing 350ma. This is more than double my V5 with the standard display. It would be nice to be able to turn off the display to save on current draw. It makes the new V6 not so portable for the folks that like to run on minimal current when portable.


On Dec 30, 2019, at 9:13 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

I believe Joel is talking about the LM7805 regulator on the Raduino.
The LM7805 is spec'd to continue working at temps as high as 150 C.

I have no idea how hot it should get on a v6 with the new display, but on the older uBitx's
the Raduino typically drew around 60ma from the 12v supply.
So about (12-5)*0.060) = 0.42 Watts dissipated as heat in the LM7805.
They figure the part rises about 19 degrees C per watt to be dissipated above the ambient air,
so 60 C does seem kind of high.  But it's not about to burn up.

Would be interesting to hear reports about how much current the Raduino on a v6 draws.

Some of the Nano's on the Raduino have been found to draw more current than others.
Some uBitx owners felt the LM7805 was way too hot, and put a heatsink on it.
The Raduino should get just as hot during receive as during transmit.

Jerry, KE7ER

On Mon, Dec 30, 2019 at 04:26 PM, Alex Netherton wrote:
Wow, when I have my SB-200 just turned on, it heats the room. When I in a long QSO, I have to open the window!

Warm finals are just a fact of life.If you are running Class B, your duty cycle is 50%, meaning that you are feeding the transistors with 20 to 25 watts, dissipating around 10 watts (or so). This will indeed heat up the heat sink, but most JFETS are rated for such temperatures. If the transistors are biased for Class AB, then you are likely putting close to 30 watts in to get 10 out.
 
Just put a hot dog on top of the finals!
Hide quoted text

 


On Fri, Dec 27, 2019 at 12:11 PM Joel Caulkins/N6ALT <caulktel@...> wrote:
Hi all,

I have my V6 all hooked up and calibrated and have checked into a few nets with my own home brew mic, the supplied one got bad reports, however I have noticed that the 5 volt regulator heat sink is running at 142 degrees F or 61.1 C. That seems hot to me. Anyone else?

Joel
N6ALT

Steve Sawicki
 

Bill,
I like the V6  and the neat touch screen  versus the V5 but WoW, the draw. 
After your message I checked and I get a reading 370ma with audio,I checked my FT-817 and it is pulling 380ma with audio it is 410ma I guess that the V6 will not be my  field QRP rig since I have a FT-817 that I have used previously and I can get a steady 5W with a 11 V 3S LIPO pack. The FT-817 which is a 20 year old design with 2M and 440  a bit dated but is still one heck of a all around QRP rig.
Best Regards.
73's
Steve
AB2ET/4

Bill
 

On Fri, Dec 27, 2019 at 12:11 PM, Joel Caulkins/N6ALT wrote:
[...] I have noticed that the 5 volt regulator heat sink is running at 142 degrees F or 61.1 C. That seems hot to me. Anyone else?
I put thermal paste on mine and the heat sink is running 70 C.  Junction temperature is probably 85-90 C, which is hot.  But as-mentioned it is within spec so it should last a while.  Cheap part so failure would only be an inconvenience.  I am going to reorient the regulator so the heat sink fins are vertical for a little better convection.

 - Bill  KB3T

Clark Martin
 

Cheap replacement unless it’s failure mode is to send Vin to Vout, then… ouch.


Clark Martin
KK6ISP

On Jan 5, 2020, at 5:01 PM, Bill <groups191227@...> wrote:

I put thermal paste on mine and the heat sink is running 70 C.  Junction temperature is probably 85-90 C, which is hot.  But as-mentioned it is within spec so it should last a while.  Cheap part so failure would only be an inconvenience.  I am going to reorient the regulator so the heat sink fins are vertical for a little better convection.

Evan Hand
 

Failure of the device can be a concern, however in the Raduino the thermal shutdown should kick in before damage to the regulator.  This will cause erratic operation of the Raduino, rather than damage.  

The above is based on the input voltage staying below the maximum value of 18 volts.  Over voltage will damage the device and cause the potential short failure.  Of course more than just the Raduino would likely be damaged in that case.

My recommendation is to add a heatsink to the regulator, especially if your are going to supply more than 12 vdc to the main board (the power amp supply is not relevant).  It is low cost and will help in keeping it below thermal shutdown.

Above are my thoughts based on my experiences.  Yours can be different.
73
Evan
AC9TU

Don - KM4UDX
 

With the 16x2 display the LM7805 was warm. Upgrade to a sexy 4.3 Nextion and the LM7805 was all nuclear core. 
Still. I suspect it would have served and suffered in silence for years and years.
Still. I put a heat sink and then moved the Nextion load to a off board buck converter.  Necessary? Not likely. Fun? Oh so much. Note I hacksawed part of the heat sink so it would not meld with the nearby toroid.
Much happiness and tropical temperatures in uBITX land.

Don
km4udx

Bill
 

On Mon, Jan 6, 2020 at 06:58 AM, Evan Hand wrote:
My recommendation is to add a heatsink to the regulator, especially if your are going to supply more than 12 vdc to the main board (the power amp supply is not relevant).  It is low cost and will help in keeping it below thermal shutdown.
Evan, the v6 comes with a substantial heat sink on the 7805.  The temperatures reported are with the heat sink.

 - Bill  KB3T

Jerry Gaffke
 

Evan,

>  The above is based on the input voltage staying below the maximum value of 18 volts. 

Where do you see 18 volts?


Yes, the LM7805 voltage regulator on the Raduino goes into thermal shutdown if it gets too hot. 
After awhile the regulator will cool off enough and the radio will start working again.

I don't see in the datasheet exactly what "too hot" is, but maximum
recommended operating temp is a junction temp of 125 C.
It can get up to 150 C before damage occurs if you accidentally
hit it with a propane torch (the "absolute maximum" temperature).
Maximum voltage into an LM7805 is 25v, but in our application anything
much above 12v into the Raduino may cause the LM7805 to get too hot.



The hfsignals.com home page says:
"Any common 3 ampere 12 linear volts supply or a set of eight AA batteries will provide enough power for this transceiver."
Never does say what the maximum recommended voltage into a uBitx v6 is.
I would not go above 13.0 volts without thoroughly investigating how hot all the parts are getting,
especially the driver transistors and emitter resistors in the transmit power amp.

I would add a 3 Amp fuse to that power supply, especially if it was capable of more than 3 Amps.
Otherwise a brief mistake may cause a smoking crater in the uBitx board somewhere.

Eight fresh AA alkaline batteries might be enough to operate the radio, but only for an hour or so.

There appears to be a connector in the v6 for an internal battery and a rudimentary battery charging scheme,
but no mention of what kind of rechargeable battery that should be.

I would go with a bank of four 18650 lithium ion cells, plus an LM2940T-12 low dropout regulator
between that battery bank and the main uBitx board (but not the Raduino, but see below).
When charging, the supply voltage into that battery bank should be limited to a max of 4.2v*4cells=16.8 volts.
The lithium ion cells should be "protected" from being shorted or overly charged or underly discharged. 
The IRF510's could be powered directly from the batteries (but through a power switch!) 
without going through the 12v regulator.

Since the Raduino draws so much power, it would be worth going to a switch mode buck converter
to replace the LM7805 out there.  Could be powered directly from the lithium ion cells along with the IRF510's.
Should be possible to build one that doesn't mess with reception, but a $1 switcher off ebay may be too noisy.

Jerry, KE7ER


On Mon, Jan 6, 2020 at 03:58 AM, Evan Hand wrote:

Failure of the device can be a concern, however in the Raduino the thermal shutdown should kick in before damage to the regulator.  This will cause erratic operation of the Raduino, rather than damage.  

The above is based on the input voltage staying below the maximum value of 18 volts.  Over voltage will damage the device and cause the potential short failure.  Of course more than just the Raduino would likely be damaged in that case.

My recommendation is to add a heatsink to the regulator, especially if your are going to supply more than 12 vdc to the main board (the power amp supply is not relevant).  It is low cost and will help in keeping it below thermal shutdown.

Above are my thoughts based on my experiences.  Yours can be different.
73
Evan
AC9TU

Evan Hand
 

I miss read the data sheet.  The actual input max is 35.  I had looked in the wrong column

I apologize for the error.

73
Evan
AC9TU

James Giercyk
 

"recommended operating temp is a junction temp of 125 C"

If your running at 125C, you've got bigger problems.  ;)

Do or Do Not. There is no try.

--- jgaffke@... wrote:

From: "Jerry Gaffke via Groups.Io" <jgaffke@...>
To: BITX20@groups.io
Subject: Re: [BITX20] uBITX V6 heat sink temperature
Date: Mon, 06 Jan 2020 09:12:27 -0800

Evan,

>  The above is based on the input voltage staying below the maximum value of 18 volts. 

Where do you see 18 volts?


Yes, the LM7805 voltage regulator on the Raduino goes into thermal shutdown if it gets too hot. 
After awhile the regulator will cool off enough and the radio will start working again.

I don't see in the datasheet exactly what "too hot" is, but maximum
recommended operating temp is a junction temp of 125 C.
It can get up to 150 C before damage occurs if you accidentally
hit it with a propane torch (the "absolute maximum" temperature).
Maximum voltage into an LM7805 is 25v, but in our application anything
much above 12v into the Raduino may cause the LM7805 to get too hot.



The hfsignals.com home page says:
"Any common 3 ampere 12 linear volts supply or a set of eight AA batteries will provide enough power for this transceiver."
Never does say what the maximum recommended voltage into a uBitx v6 is.
I would not go above 13.0 volts without thoroughly investigating how hot all the parts are getting,
especially the driver transistors and emitter resistors in the transmit power amp.

I would add a 3 Amp fuse to that power supply, especially if it was capable of more than 3 Amps.
Otherwise a brief mistake may cause a smoking crater in the uBitx board somewhere.

Eight fresh AA alkaline batteries might be enough to operate the radio, but only for an hour or so.

There appears to be a connector in the v6 for an internal battery and a rudimentary battery charging scheme,
but no mention of what kind of rechargeable battery that should be.

I would go with a bank of four 18650 lithium ion cells, plus an LM2940T-12 low dropout regulator
between that battery bank and the main uBitx board (but not the Raduino, but see below).
When charging, the supply voltage into that battery bank should be limited to a max of 4.2v*4cells=16.8 volts.
The lithium ion cells should be "protected" from being shorted or overly charged or underly discharged. 
The IRF510's could be powered directly from the batteries (but through a power switch!) 
without going through the 12v regulator.

Since the Raduino draws so much power, it would be worth going to a switch mode buck converter
to replace the LM7805 out there.  Could be powered directly from the lithium ion cells along with the IRF510's.
Should be possible to build one that doesn't mess with reception, but a $1 switcher off ebay may be too noisy.

Jerry, KE7ER


On Mon, Jan 6, 2020 at 03:58 AM, Evan Hand wrote:

Failure of the device can be a concern, however in the Raduino the thermal shutdown should kick in before damage to the regulator.  This will cause erratic operation of the Raduino, rather than damage.  

The above is based on the input voltage staying below the maximum value of 18 volts.  Over voltage will damage the device and cause the potential short failure.  Of course more than just the Raduino would likely be damaged in that case.

My recommendation is to add a heatsink to the regulator, especially if your are going to supply more than 12 vdc to the main board (the power amp supply is not relevant).  It is low cost and will help in keeping it below thermal shutdown.

Above are my thoughts based on my experiences.  Yours can be different.
73
Evan
AC9TU