I experienced some regular uploading issues, and I am not th elonly one reading the forum
(http://forum.arduino.cc/index.php?topic=574627.0) . Then I decided to prepare some spare parts. Here, I prepare chips for my Arduino Uno R3 board.

Explanations

The heart of Arduino board is the removable chip. IT is called ATMEGA328P. THis chip can be bought for less than 1 dollar. I bought four of them.

Those chips allowed to externalize a prototype outside the Uno Board. But they can serve also as spares for your arduino board to correct uploading issues. But to prepare them, you need a working Uno board ! Let’s prepare them in advance, before having a issues with our main board !

Set Up

We set up the following assemply, which is described here.

To do this, we need:

• uan oscillator cadenced at 16Mhz
• a 10 k-Ohm resistor
• 18 to 22 pico farad capacitors

ATMEGA chip is the heart of this assembly.

Burn the bootloader

From the Arduino IDE, we go through the following steps:

• Load in the IDE scénario ArduinoISP via : File/Example/11.ArduinoISP/ArduinoISP
• Upload it on Arduino board
• Choose to use R3 board as programmer via Tools/Programmer/Arduino as ISP

Then our R3 board can be used as a gate to our chip.

• We choose Uno Board via Tools/Boards/Arduino-Genuino Uno, which will configure our external chip to be compatible to Uno boards.
• We burn the bootloader to the chip through Tools/Burn bootloader

After few seconds, the external ATMEGA chip is configured as identical to the one embedded in the R3 board. Which means that you can exchange one by the other at any time. If any uploading issue happen on your genuine board, ojne of the possible causes may be a corrupted bootloader within the genuine chip. With those steps, you have spares !

A comment on oscillators frequencies

We described another assembly here (
http://randomcraftr.com/?p=224). It was simpler, without external oscillator. This allowed to have autonomous assembly without a Uno board, but not to replace the chip within the board. Indeed, ATMEGA328P has a embedded oscillator working at 8MHz which can be enough for assembly outside the Uno board. But to remplace Uno board chip, you must configure your spare with a 16MHz oscillator, else it will not work.