I am new to Arduino... Just started with purchase of an Arduino Uno
Was Working with the development board last one week... Successfully tested the BlinK and Push button and LED circuits...
In the second phase set up the LCD circuit and tried to upload and run the LCD ... With 470 ohm connected to Pin 15 and voltage to pin 3 set through a 10k ohm pot.... I used a wall mounted Ac/Dc Power supply at 12 V..
However the LCD remained dark and did not light up... I checked the voltage at LCD pins and found the following with reference to the GND at pin 1 of the LCD :
Input DC at pin 2 ---- 4.72 V
Set the Voltage at VE at 3.4 V
Voltage at Pin 5 at 0 volts
Voltage at pin 15 at 3.6 v
Voltage at pin 16 at 0 V
To check LCD I took out all the 6 the data and control wires to the LCD ... No change observed in the LCD
Now to check whether the UNO board was ok, wired up the earlier circuit and tried to upload the earlier saved sketch...
The Arduino IDE announced unable to upload and to check up with Trouble shooting...
Then observed the following following in the Uno board with all the connection to the external circuit removed :
With both the USB cable from PC ( PC running) and the Power Supply connected to UNO --- LED of Pin 13 of board lights up and keeps glowing...
With just the USB cable from PC ( PC running) connected to Uno --- LED of Pin 13 of board lights up and keeps glowing...
With just the DC Power Supply connected to Uno --- LED of Pin 13 of board stops glowing and Tx and Rx LEDs of board light up and keep glowing ...
It is requested that the problem be analyzed and the solution may kindly be forwarded
Jean Mark .... AS indicated in my post ... already done what you say before sending the SOS mail.... Tried the blink and others but the Arduino IDE does upload the sketch at all and hence there is no question of the uno working... Please check with the detail observation I have sent with the mail and respond please....
It sounds like the bootloader is corrupted.
You need to burn it again.
You can use another Arduino as ISP programmer.
Search the forum for "burn bootloader".
It could be that something on the board has burned out.
Are any of the components really hot to touch?
Can you use a volt meter, and check the 12 volt, and the 5 volt, and 3.3 volt points?
The last sketch that you were able to upload successfully, did it include the "blink LED"? If the problem is that you can't upload a new sketch, the arduino should be running the last one that was uploaded.
Thanks for your call.... My replies are as follows
Tried to work with the last sketch (ie before the LCD was tried)... But the circuit did not work
I put on wall mounted supply ... result was the Pin 13 LED which glowing permanently - went off and has remained so till now... the Tx and Rx Leds are also not glowing...
The ATMEga 328 got bit hot ... But the crystals, the all LEDs have got more hotter but can be touched ... temp looks to be about 40 to 45 degree Celsius...
The 5 V Dc voltage s down 3.24 v
No component is presently getting heated with just connecting the USB cable to the board but the 5v DC now is 4.34 v.
Have u tried to re-burn the bootloader?
You need to at least try that even if it is just to rule it out as the problem.
Troubleshooting should be done step-by-step and not in a million directions at once.
@aisc, I don't think that "re-burn the bootloader" will solve the problem of "The 5 V Dc voltage s down 3.24 v
I could be wrong tho.
"Troubleshooting should be done step-by-step and not in a million directions at once."
There many ways to do troubleshooting. My favorite is: to consider the problem, think of what would be the most likely based on information at hand, and test for that.
Based on the voltage readings, I suspect the board has been damaged (sorry to say).
I assume you tried more than one power source to test the voltage.