with a probable short my arduino nano won't load anything and wont connect to my pc, but it powers on and the power led is always on. in i short reset with ground it connects to my pc but still won't load. i did figure out the problem and its a small chip with "SL" on the top of it.
What makes you think that the diode is a problem?
What does that mean?
You have a Nano look-alike using a CH340 USB chip. Do you have the CH340 driver for Windoze installed?
Hi @dm123
@Paul_B, I think he is saying that the diode is the problem as there seems to be apparent damage on the left side of it.
Is that right @dm123?
The diode appears to be soldered sloppily and blown also.
I am pretty sure that diode is this in the official schematic:
Do you know if you damaged the board in any way? Shorted it, etc.
Try programming it while the nano is hooked up to an external 5v supply.
Also, it looks like that nano is an aftermarket. Try programming it with the "Old Bootloader" selected in the IDE. Do you have a link to that nano? Are you using windows or macOS?
i checked it with a multimeter the bad ones are 3-5 ohm the good one is 1.56 ohm and the damage on the side of it is from soldering because i switched it with a good one and it did turn on and work normaly it uploads and connects with no problem. when i solder a cable between the reset and the ground pin it connects to my pc but won't upload to the arduino
I have had a couple of incidents over the years when I accidentally connected external power to Nanos the wrong way round and they stopped working
Both were brought back to life by replacing the Schottky diode. I don't remember how I worked out what to replace them with, but looking at my stock of SMD components the only diodes that I have are marked B2Y and the accompanying delivery note describes them as MBR0520LT1G 20V 0.5A Schottky diodes
Amazon has 1000pcs for $55:
Digikey also has them:
the damage on the side of the diode is from soldering because i replaced it with a good one and it worked fine with a good diode.
i think there was a short from a led with a damaged cable.
i tried it with a external power supply and it connects and uploads.
I think that proves that it is the USB power selector diode as I pointed out in reply #3.
You already replaced that diode before?
no i just had 1 other good arduino and tried it to be sure that. that is what i need to get.
