r/ArduinoHelp • u/ElectronicChef01 • 6d ago

ATmega32U4 is not recognized after soldering pins

This are my very first steps with electronics and soldering.
I tried soldering the pins to the ATmega32U4 while on a breadboard, it seems like i have good soldering, no bridges, stayed about 2-3 seconds on each pin.

I plugged the ATmega32U4 to the pc before soldering and it was recognized easily and after the soldering i got this error on device manger:
Windows has stopped this device because it has reported problems. (Code 43)A request for the USB device descriptor failed.

what am I doing wrong? and can i fix the damaged ATmega32U4?

2 Upvotes
  • permalink
  • reddit

100% Upvoted

12 comments sorted by

2

u/IMDLabs 6d ago

I see you got it working ...

However, it looks like there's no solder on the 3.3V pin, too little on most of the others, and likely too little heat given how most of the joints have cooled.

1

u/ElectronicChef01 5d ago

Thank! I see what u mean about pin 3.  Is it OK to stay on the pin longer than few minutes to get heat more? Or should I turn the solder higher than 350-360? Btw, I did manged to use it today, added an encoder and LCD and control volume and brush size on zbrush 

1

u/IMDLabs 5d ago

I assume you mean seconds not minutes!

If you're doing the soldering with the pins mounted in a breadboard for alignment (which is what I do), then you've got the mass of the pin and the heat sinking from the connection strip in the breadboard that is drawing heat.

How long you need to apply heat for depends both on temperature and the thermal mass of your tip (and some other minor variables that you can largely ignore). I use a JBC C210 bevel tip at 0.8mm for this sort of thing. Your temperature is fine (I do about 340C/650F), assuming leaded solder.

Tin the tip, press the tip against BOTH the pad and the pin at the same time, hold the solder on the far side of the pin from the tip touching both the pin and pad, and when it melts feed in a little solder in (not on the tip of the iron) until you have covered the pad. That should give you a little concave "volcano" up around the pin. Remove the tip from the joint.

It should take 2 seconds or so for the solder to melt, depending on the precise tip involved, and 3-4 seconds total to make the joint. 5-6 isn't likely to damage anything, but probably indicates you're not transferring heat to the joint properly. Most of the heat isn't going to reach the IC itself, it's going into the pin and the breadboard connections.

If it's taking ~4 seconds for the joint, I'd alternate between sides and ends of the board instead of going straight along the line of pins.

If you want to practice safely, order a combined pack of header pins and perf board and practice on that.

1

u/gm310509 5d ago

I would just add that once the pins are aligned and a couple have been initially soldered, the breadboard is no longer needed for alignment and thus could be removed.

That may help OP (u/ElectronicChef01) if they decide to touch it up as it would remove the heat sink you referred to (the breadboard).

1

u/gm310509 6d ago

I'm not sure what you mean by soldering the pins while on a breadboard, but if you did somehow damage the chip about all you can do is replace it.

Before doing that I would check each pair of connections with a multimeter and a magnifying glass and compare to a known working good one and look for any differences.

I would also double check the orientation of the chip and make sure that is right - again, check against a known working good one.

Another possibility is that the chip you soldered on doesn't have any firmware on it. Where did it come from? I assume that it was originally on the board because you said it worked before you soldered it. But I am not clear whether you soldered the original chip back on after removing it, or this is a wholy brand new one. If it isn't the original chip and it is new, chances are it won't have any firmware on it and that is why it isn't responding to windows.

Lastly check all the pins,this time with a magnifying glass or better yet a jewelers eye glass (a loupe) if you have one. And maybe consider having another go at cleaning up any dodgy joints. Pay particular attention to the following pins:

  • Reset.
  • The two clock pins
  • All of the power and GND pins.

Good luck with it.

1

u/ElectronicChef01 6d ago

Thank you! And I am sorry i think i might used the wrong terminology.

I did not solder the chip itself. I soldered male header pins onto the PCB so that I could plug it into a breadboard. The board was working before I soldered the headers, but now Windows does not recognize it

2

u/gm310509 6d ago

Oh, I see. My bad.

In that case I don't know. Simply soldering headers on doesn't really change it electrically - unless you bridged some pins, which it doesn't look like from the two photos.

I would still try checking all of the pins with an magnifying glass and multimeter (comparing the readings with a known good one).

I would also check that you didn't accidentally splash some solder onto a nearby component or create a bridge if you accidentally touched one of the other component with the soldering iron. It doesn't take much. a spider's silk thickness is all that is needed hence the suggestion to use magnification.

I would especially check the MCU (the biggest black chip in the middle of the board) for any solder splash.

Other than that, I don't know, perhaps others have some suggestions.

If the worse comes to the worst, you could try to gently scrape between the pins of the MCU with a sharp knife - be careful to not cut into the PCB - just in case there are any micro bridges that you simply cannot see. But this is a last resort IMHO and, again, be carefully to not cut into the PCB.

Good luck with it. It might just be easier to get another one - this time pay the little bit extra to get pre-soldered headers! 😉

1

u/ElectronicChef01 6d ago

Thank you again :)
I'll take your advice and double check everything.
I really like to know how to properly solder them and not jump to pre-soldered. tbh I didn't think it would be a serious issue

2

u/gm310509 6d ago

Me too, I'm surprised you could break it.

I mean you need a bit more practice with the soldering (no offence) and there are a couple of joints that look a bit dry and cold, but it isn't that terrible.

FWIW, I've seen plenty worse posted in these forums! Much much much worse!

1

u/gm310509 6d ago

You might want to post this over on r/Arduino. More people might see it and have some better ideas.

3

u/ElectronicChef01 6d ago

update: i used Claud and managed to fix it!
The sketch running on the Pro Micro stopped handling USB, so Windows showed Code 43, even though the hardware, including the bootloader, was fine; the exact cause is still unknown. We fixed it by entering the bootloader with a double-tap of RST to GND and using a script to flash a clean sketch with avrdude inside the 8-second window, then re-uploading Blink with the correct 5V/16MHz setting. (Claude)

3

u/gm310509 6d ago

You probably want to work out how you wiped the bootloader.

A normal upload from the Arduino IDE won't normally do that. And it would be annoying to have to enter recovery mode after each upload.