Hi Nick, Component wires connected to a ground plane can be difficult to solder or to desolder as the copper of the ground plane conducts the heat of the soldering iron away. This is especially true when using lead free solder or on multilayer pcbs. For non commercial soldering work, I usually recommend leaded solder (Sn63Pb37). Unfortunately, it is not always possible to avoid connections to ground planes, but for such connections, we usually use thermal relief pads which make soldering somewhat easier. For desoldering a TO92 component like T9 you can use one of the following methods:   connect all three pads together with one blob of solder and heat the blob until everything is melted and you can pull the transistor out of the pcb from the other side. Then remove the solder with desoldering wick and make sure there is no solder left in the holes of the soldering pads. Finally clean the PCB using isopropyl alcohol to remove any flux residues.   another trick consists of adding some low temperature bismuth solder paste to the pads and melt it together with the existing solder. This lowers the melting point of the solder and makes desoldering easier. Use desoldering braid/wick to remove the excess solder and clean the pcb with isopropyl alcohol. This works similar to the well known ChipQuik desoldering wire, but is considerably cheaper. Ilse

Your description and the way how Windows searches for DLLs brought me to the simple solution. It just depends on how the IDE is started. The order in which DLLs are searched is: 1. The directory where the executable module for the current process is located. 2. The current directory. 3. The Windows system directory. 4. The Windows directory. 5. The directories listed in the PATH environment variable. Here, path 1 is the tools\avrdude\6.3.0-arduino2\bin directory. In your case, path 2 is the Arduino directory which contains Arduino.exe if the IDE is started by executing Arduino.exe via the Start menu, desktop shortcut icon or direct start of Arduino.exe. However, in my case, path 2 is the directory which contains the ino-file of a sketch if the IDE is started by double-clicking the ino-file. To prove my finding, I moved libusb0.dll from the tools\avrdude\6.3.0-arduino2\bin folder to the folder which contains the sketch and double-clicked the ino-file. Of course, upload succeeded. So, it is just a problem that the Arduino team forgot to include libusb0.dll in the bin folder of the 6.3.0-arduino2 zip-archive.

Hello Axiris, Thank you for your quick responce. I am looking forward to the next firmware release I want to say that it is a nice clock to build. I enjoyed it. But I have one disadvance about the PCB design. I don't like that both side of the PCB has a ground plane. It was difficult to replace T9 because all the heat from my solder iron was disappeared into the ground plane. I don't know if someone else has a solution for this problem. This was the only drawback I can find so far. Nick  

Hello,   for a quick manufacturing, I chose http://www.allpcb.com currently, it's around $ 20 for 10 PCBs (arduino format) delivered in 7 days, or $ 15 for 10 PCB 50x50mm The follow-up of the production is very detailed In december 2017, I paid $5 for 10 PCBs delivered in 7 dayshttps://twitter.com/laurent_le_goff/status/946137177641111554 for my arduino 1284 (https://github.com/llegoff/bobuino)  

Because that sounds like a plausible explanation, I searched my computer and found libusb0.dll in 24 places on the C drive and 36 places on the D drive... Too many to clean up so I took another Windows 10 PC and deleted all instances of libusb0.dll and with that everything remotely related to Arduino. I then scanned the PC again to make sure that libusb0.dll was really gone. I downloaded the Arduino IDE 1.8.5 ZIP file, installed it and rebooted the computer. Rescanning it for libusb0.dll resulted in four instances all located in the fresh Arduino installation. I installed the Uno R4 Boards package from GitHub through the Boards Manager, connected the Uno R4 and loaded the BlinkWithoutDelay example. It compiled without errors and then uploaded to the board without errors. Deleting once again all (4) instances of libusb0.dll now finally resulted in an upload error, but it went away after placing the DLL back to the folder where arduino.exe lives. To me this seems to indicate that it is not necessary to have a libusb0.dll in the avrdude folder.