user51773: I am using RTC DS1307 with "TINY RTC I2C modules" written on it.I had downloaded RTClib library from adafruit and using the example code. I connected GND->GND, VCC->5V, SDA->A4 and SCL->A5. However after connecting the VCC to 5V the "ON" Led does not lights up and the code is not getting uploaded. I tried connecting the VCC to 3.3 V the code gets uploaded but does not shows any output on the screen. 

user52137: It seems an hardware problem on Arduino Uno board.
Try to connect the 5V pin of Arduino Uno to a digital pin (e.g D7) and write a program for read a digital pin.
int inPin = 7;     // digital pin 7
int val = 0;       // variable to store the read value

void setup()
{
  pinMode(inPin, INPUT);        // sets the digital pin 7 as input
}

void loop()
{
  val = digitalRead(inPin);     // read the input pin
  Serial.println(val);          // print read value on serial
}

If you're not able to load this sketch on your Arduino, most likely it's an hardware problem on Arduino.

user51773: Soldering was not done properly. The vcc and ground got "short" that's what the shopkeeper said. We again soldered it on the other side. Now its working 

51773: <p>I am using RTC DS1307 with "TINY RTC I2C modules" written on it.I had downloaded RTClib library from adafruit and using the example code. I connected GND->GND, VCC->5V, SDA->A4 and SCL->A5. However after connecting the VCC to 5V the "ON" Led does not lights up and the code is not getting uploaded. I tried connecting the VCC to 3.3 V the code gets uploaded but does not shows any output on the screen. </p>
 52137: <p>It seems an hardware problem on Arduino Uno board.</p>

<p>Try to connect the 5V pin of Arduino Uno to a digital pin (e.g D7) and write a program for read a digital pin.</p>

<pre><code>int inPin = 7;     // digital pin 7
int val = 0;       // variable to store the read value

void setup()
{
  pinMode(inPin, INPUT);        // sets the digital pin 7 as input
}

void loop()
{
  val = digitalRead(inPin);     // read the input pin
  Serial.println(val);          // print read value on serial
}
</code></pre>

<p>If you're <strong>not</strong> able to load this sketch on your Arduino, most likely it's an hardware problem on Arduino.</p>
 51773: <p>Soldering was not done properly. The vcc and ground got "short" that's what the shopkeeper said. We again soldered it on the other side. Now its working </p>
