Arduino ethernet hangs after less than a minute, but not on USB

i have arduino uno + ethernet shield + 9V/200mA adapter. I am trying to send some data with HTTP connection. When it’s connected to USB it works perfectly, but when i plugged out USB, hangs (after less than a minute, it stops pinging).

I have tried: this

EthernetClient.cpp

int EthernetClient::connect(IPAddress ip, uint16_t port) {
  if (_sock != MAX_SOCK_NUM)
    return 0; // i changed to -1  as suggested on previous link

  for (int i = 0; i < MAX_SOCK_NUM; i++) {
    uint8_t s = socketStatus(i);
    if (s == SnSR::CLOSED || s == SnSR::FIN_WAIT || s == SnSR::CLOSE_WAIT) {
      _sock = i;
      break;
    }
  }

and also example from library Examples-library-WebClientRepeating, but i get the same problem as in my code. Is maybe my adapter to weak?

This code is from Example WebClientRepeating:

#include <SPI.h>
#include <Ethernet.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED    };

// fill in your Domain Name Server address here:
IPAddress ip(193, 77, 60, 66);
IPAddress subnet(255, 255, 255, 0);
IPAddress gateway(193, 77, 60, 7);
IPAddress myDns(193, 77, 60, 213);

EthernetClient client;

char server[] = "www.arduino.cc";
//IPAddress server(64,131,82,241);

unsigned long lastConnectionTime = 0; // last time you connected to the server, in millisecond
const unsigned long postingInterval = 10L * 1000L; // delay between updates, in milliseconds
// the "L" is needed to use long type numbers

void setup() {
  // start serial port:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // give the ethernet module time to boot up:
  delay(1000);
  // start the Ethernet connection using a fixed IP address and DNS server:
  Ethernet.begin(mac, ip, myDns, gateway, subnet);

  // print the Ethernet board/shield's IP address:
  Serial.print("My IP address: ");
  Serial.println(Ethernet.localIP());
}

void loop() {
  if (client.available()) {
    char c = client.read();
    Serial.write(c);
  }

  // if ten seconds have passed since your last connection, then connect again and send data:      
  if (millis() - lastConnectionTime > postingInterval) {
    httpRequest();
  }    
}

// this method makes a HTTP connection to the server:
void httpRequest() {
  // close any connection before send a new request.
  // This will free the socket on the WiFi shield
  client.stop();

  // if there's a successful connection:
  if (client.connect(server, 80)) {
    Serial.println("connecting...");
    // send the HTTP PUT request:
    client.println("GET /latest.txt HTTP/1.1");
    client.println("Host: www.arduino.cc");
    client.println("User-Agent: arduino-ethernet");
    client.println("Connection: close");
    client.println();

    // note the time that the connection was made:
    lastConnectionTime = millis();
  }
  else {
    // if you couldn't make a connection:
    Serial.println("connection failed");
  }
}

The ethernet shield is a bit of a power eater. Try a power adapter with more power capability. I use a 7.5V 1A wall wart, and it works ok. A 9V 500ma or greater should be ok.

Does sound like it needs more power. I use my arduino plugged into a USB wall socket, the Ethernet shield only works with the bigger iPad PSU’s which I think are a couple of amps.