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Forum Index : Microcontroller and PC projects : Pico Computer 3 / U21
| Author | Message | ||||
| PhenixRising Guru  Joined: 07/11/2023 Location: United KingdomPosts: 2075 |
I only have a mouse connected. Does this look reasonable?   |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 11814 |
Have you done the usb hub mod? |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 2075 |
No. As it came but I seem to remember reading about something getting too hot? |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 11814 |
Without the mode the hub 3.3V regulator and the lm1117 fight each other. |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 2075 |
They were built 21st August and I believe that I uploaded the latest files. Does it still need the mod?  Edited 2026-09-03 04:05 by PhenixRising |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 2075 |
Update. Not sure I trust this thermal imaging camera. This U21 is not what I would call hot-to-the-touch  |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3374 |
The temperature scale at the right indicates a maximum of 54°C, which isn't hot to a fingertip. That is why testing the temperature of a baby's bathwater is done with the elbow. The pic. nicely shows the problem with thermal cameras. The shiny heatsink tab shows up as just above ambient temperature but is actually the hottest part. The slightly cooler black body of the regulator will have a thermal emissivity close to the value the camera is calibrated for so will be fairly accurate. |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2247 |
Phenix After I had used one of my pico3's for over 8 hours straight I got my IR temp gauge which has 2 laser pointers and focused right in to the reg and pico now both showed 2C over ambient and what really surprised me was the USB hub chip which hasn't had that mod done was even cooler than the pico. From what I read about the USB chip and it's fault is when both USB cables are used so my method have the pico in the off condition turn off the hub using the switch insert the mircoUSB while holding down the boot button and the pico is shown straight away on my computer. Now if I leave that programming cable on it will boot the pico so once the pico icon disappears from the file list on the computer the microUSB is disconnected the hub switch turned on and boot as normal. This ensures there is no fighting of voltages so nothing gets hot  Regards Bryan |
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Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 6081 |
If this is powering the pico running at 370Mhz, the wifi chip, the hub, the audio, the psram and flash, the current can easilly exceed 200mA. At 1.7V drop that is near 400mW. A temp rise of 30 degrees is normal. Volhout Edited 2026-09-03 14:54 by Volhout PicomiteVGA PETSCII ROBOTS |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 9104 |
We used to say that if you spit on it and it boils off it's too hot. It's not totally inaccurate as a silicon device will almost always be ok at 100C. It makes a bit of allowance for the die temperature being quite a bit hotter than the encapsulation. If the manufacturers logo is burned into your fingertip when you touch a hot device you may have a problem. :) Mick Zilog Inside! nascom.info for Nascom & Gemini |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4377 |
I thought it was if you spit at it and it spits back then it's too hot. John |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 9104 |
hehe... I like it when the plastic has been so hot that it's cracked. Easy overheating problem to spot. :) Mick Zilog Inside! nascom.info for Nascom & Gemini |
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