CSV file read stops after 9 lines?

Using Arduino Programming Questions
22

I loaded test.txt with 20 lines of CSV text with three numbers (all numbers <= 255), and this got them all.

#include <SD.h>
char netBuffer[32];
byte myTest[3];

void setup() {
  Serial.begin(9600);
  // disable w5100
  pinMode(10,OUTPUT);
  digitalWrite(10,HIGH);
  
  Serial.print("Starting SD...");
  if(!SD.begin(4)) Serial.println("failed");
  else Serial.println("ok");
  
  File fh = SD.open("test.txt",FILE_READ);
  int chPos = 0;
  int lineNo = 0;
  
  if(!fh)
  {
    Serial.println("SD open fail");
    return;    
  }

  while(fh.available())
  {
    char ch = fh.read();
    if(ch == '\n') {
      chPos = 0;

      sscanf(netBuffer,"%u,%u,%u",&myTest[0],&myTest[1],&myTest[2]);  

      Serial.print(netBuffer);

      Serial.print("  A = ");
      Serial.print(myTest[0]);
      Serial.print(" B = ");
      Serial.print(myTest[1]);
      Serial.print(" C = ");
      Serial.println(myTest[2]);
      
      lineNo++;
    }
    else if(ch == '\r') {
      // do nothing
    }
    else if(chPos < 31) {
      netBuffer[chPos] = ch;
       chPos++;
      netBuffer[chPos] = 0;
    }
  }
  fh.close();
}

void loop() {
}

edit: Removed extra blank lines.