user70301: I'm trying to power on my NodeMCU ESP8266 Ver 0.1 (thats what is written in board), via VIN and Ground with my phone charger.
I'm 100% sure that the USB charger is working, providing 5V, and that the ground and VIN are connected to the right positions.
If I use the same phone charger via the NodeMCU USB, the program blinks the builtin led alright.
If I power via VIN, it flashes when I connect the charger to DC, but the program does not work.
It seems as the NodeMCU is not powering on complety.
Bizarrely, if I short 3V and G pins, the board starts working normally as powered directly via USB port.
This is the code
/*
 ESP8266 Blink by Simon Peter
 Blink the blue LED on the ESP-01 module
 This example code is in the public domain
 
 The blue LED on the ESP-01 module is connected to GPIO1 
 (which is also the TXD pin; so we cannot use Serial.print() at the same time)
 
 Note that this sketch uses LED_BUILTIN to find the pin with the internal LED
*/

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);     // Initialize the LED_BUILTIN pin as an output
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, LOW);   // Turn the LED on (Note that LOW is the voltage level
                                    // but actually the LED is on; this is because 
                                    // it is acive low on the ESP-01)
  delay(1000);                      // Wait for a second
  digitalWrite(LED_BUILTIN, HIGH);  // Turn the LED off by making the voltage HIGH
  delay(2000);                      // Wait for two seconds (to demonstrate the active low LED)
}



user81151: I faced the same issue. My problem was on this version of board both ground (G) pins on the side of Vin pin (I say left side of the board when usb is towards bottom direction) do not have connection with the ground of the 3.3v regulator or to the Gnd pin on right side of the board !! No continuity from ground pin to regulator is the problem I understood. The moment I connected 5v between Vin and Right side 'G' pin it started working. Check and try if not resolved yet.

70301: <p>I'm trying to power on my NodeMCU ESP8266 Ver 0.1 (thats what is written in board), via VIN and Ground with my phone charger.</p>
<p>I'm 100% sure that the USB charger is working, providing 5V, and that the ground and VIN are connected to the right positions.</p>
<p>If I use the same phone charger via the NodeMCU USB, the program blinks the builtin led alright.</p>
<p>If I power via VIN, it flashes when I connect the charger to DC, but the program does not work.
It seems as the NodeMCU is not powering on complety.</p>
<p>Bizarrely, if I short 3V and G pins, the board starts working normally as powered directly via USB port.</p>
<p>This is the code</p>
<pre><code>/*
 ESP8266 Blink by Simon Peter
 Blink the blue LED on the ESP-01 module
 This example code is in the public domain
 
 The blue LED on the ESP-01 module is connected to GPIO1 
 (which is also the TXD pin; so we cannot use Serial.print() at the same time)
 
 Note that this sketch uses LED_BUILTIN to find the pin with the internal LED
*/

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);     // Initialize the LED_BUILTIN pin as an output
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, LOW);   // Turn the LED on (Note that LOW is the voltage level
                                    // but actually the LED is on; this is because 
                                    // it is acive low on the ESP-01)
  delay(1000);                      // Wait for a second
  digitalWrite(LED_BUILTIN, HIGH);  // Turn the LED off by making the voltage HIGH
  delay(2000);                      // Wait for two seconds (to demonstrate the active low LED)
}
</code></pre>
<p><a href="https://i.stack.imgur.com/xZy0X.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xZy0X.jpg" alt="This is the wiring" /></a></p>
 81151: <p>I faced the same issue. My problem was on this version of board both ground (G) pins on the side of Vin pin (I say left side of the board when usb is towards bottom direction) do not have connection with the ground of the 3.3v regulator or to the Gnd pin on right side of the board !! No continuity from ground pin to regulator is the problem I understood. The moment I connected 5v between Vin and Right side 'G' pin it started working. Check and try if not resolved yet.</p>
