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Metro M4 Express Power - 9V 1000mA - Heat
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Metro M4 Express Power - 9V 1000mA - Heat

by bear_tactics on Thu Oct 08, 2020 7:48 am

Good morning,

I bought a 9V 1000mA power cable for my M4 but I am finding that the board gets very hot when I use this supply. I switched it to a USB 5V cable and no temperature issues are occurring.

I prefer to use the 9V DC power jack for powering the board in my project. Is there some other cable that can be used that won't over-heat the board?

Thank you.

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Re: Metro M4 Express Power - 9V 1000mA - Heat

by dastels on Thu Oct 08, 2020 10:07 pm

A 9v supply should be fine. What area of the board gets hot. And what do you mean by *very* hot? The 5v regulator is dropping the extra 4v which will generate some heat. Supplying 5v through the DC jack isn't recommended as the regulator does need something in excess of 5v (6-12 is best).

Dave

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Re: Metro M4 Express Power - 9V 1000mA - Heat

by User_UMjT7KxnxP8YN8 on Fri Oct 09, 2020 1:59 am

I once put a Metro M4 Express with a Wiznet 5500 Ethernet Shield in a closed ESD bag with a 9V power supply attached. I then applied a load that pushed it as hard as possible for an hour and its temperature increased by about 10 degrees F, and that was localized at the regulator.

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Re: Metro M4 Express Power - 9V 1000mA - Heat

by bear_tactics on Fri Oct 09, 2020 11:35 am

The heat is close to the regulator. I don't have an exact reading but touching it feels pretty hot. I would guess close to 120ºF.

I don't think I am pushing the board very hard. I have a sensor on the SDA/SCL and a display on the SPI pins. The sensor data is displayed on the HMI. No other process is going on.

Does the Amperage make a difference in the amount of heat put off?

Also, I don't have 5V going into the 9V port. The 5V is from the USB power.

Thanks again.

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Re: Metro M4 Express Power - 9V 1000mA - Heat

by User_UMjT7KxnxP8YN8 on Fri Oct 09, 2020 11:51 am

Just curious... do you have the switch next to the external power connector on the Metro M4 in the "on" position?

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Re: Metro M4 Express Power - 9V 1000mA - Heat

by dastels on Fri Oct 09, 2020 12:50 pm

Cool about the 5v.

If you connect the 9v with nothing else connected, does it heat up the same?

Dave

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