user37949: New Adafruit GPS connected to my Arduino 101 board. 
When trying to use the RX/TX hardware serial (on digital pins 0 / 1), with a simple sketch (described by Adafruit) to output a serial response, I'm not seing anything in the serial monitor (9600 baud).
// this sketch will allow you to bypass the Atmega chip
// and connect the Ultimate GPS directly to the USB/Serial
// chip converter.

// Connect VIN to +5V
// Connect GND to Ground
// Connect GPS RX (data into GPS) to Digital 0
// Connect GPS TX (data out from GPS) to Digital 1

void setup() {}
void loop() {}

Wires connected as in the sketch, also tried swapping them out in case of faulty wire.
Went on to try TinyGPS++ default example code, across a variety of pins: 3,4 & 8,9 & 0,1. 
#include <TinyGPS++.h>
#include <SoftwareSerial.h>
/*
   This sample code demonstrates the normal use of a TinyGPS++ (TinyGPSPlus) object.
   It requires the use of SoftwareSerial, and assumes that you have a
   4800-baud serial GPS device hooked up on pins 4(rx) and 3(tx). EDITED BELOW.
*/

static const int RXPin = 8, TXPin = 9;
static const uint32_t GPSBaud = 9600;

// The TinyGPS++ object
TinyGPSPlus gps;

// The serial connection to the GPS device
SoftwareSerial ss(RXPin, TXPin);

void setup()
{
  Serial.begin(9600);
  ss.begin(GPSBaud);

  Serial.println(F("FullExample.ino"));
  Serial.println(F("An extensive example of many interesting TinyGPS++ features"));
  Serial.print(F("Testing TinyGPS++ library v. ")); Serial.println(TinyGPSPlus::libraryVersion());
  Serial.println(F("by Mikal Hart"));
  Serial.println();
  Serial.println(F("Sats HDOP Latitude   Longitude   Fix  Date       Time     Date Alt    Course Speed Card  Distance Course Card  Chars Sentences Checksum"));
  Serial.println(F("          (deg)      (deg)       Age                      Age  (m)    --- from GPS ----  ---- to London  ----  RX    RX        Fail"));
  Serial.println(F("---------------------------------------------------------------------------------------------------------------------------------------"));
}

void loop()
{
  static const double LONDON_LAT = 51.508131, LONDON_LON = -0.128002;

  printInt(gps.satellites.value(), gps.satellites.isValid(), 5);
  printInt(gps.hdop.value(), gps.hdop.isValid(), 5);
  printFloat(gps.location.lat(), gps.location.isValid(), 11, 6);
  printFloat(gps.location.lng(), gps.location.isValid(), 12, 6);
  printInt(gps.location.age(), gps.location.isValid(), 5);
  printDateTime(gps.date, gps.time);
  printFloat(gps.altitude.meters(), gps.altitude.isValid(), 7, 2);
  printFloat(gps.course.deg(), gps.course.isValid(), 7, 2);
  printFloat(gps.speed.kmph(), gps.speed.isValid(), 6, 2);
  printStr(gps.course.isValid() ? TinyGPSPlus::cardinal(gps.course.value()) : "*** ", 6);

  unsigned long distanceKmToLondon =
    (unsigned long)TinyGPSPlus::distanceBetween(
      gps.location.lat(),
      gps.location.lng(),
      LONDON_LAT, 
      LONDON_LON) / 1000;
  printInt(distanceKmToLondon, gps.location.isValid(), 9);

  double courseToLondon =
    TinyGPSPlus::courseTo(
      gps.location.lat(),
      gps.location.lng(),
      LONDON_LAT, 
      LONDON_LON);

  printFloat(courseToLondon, gps.location.isValid(), 7, 2);

  const char *cardinalToLondon = TinyGPSPlus::cardinal(courseToLondon);

  printStr(gps.location.isValid() ? cardinalToLondon : "*** ", 6);

  printInt(gps.charsProcessed(), true, 6);
  printInt(gps.sentencesWithFix(), true, 10);
  printInt(gps.failedChecksum(), true, 9);
  Serial.println();

  smartDelay(1000);

  if (millis() > 5000 && gps.charsProcessed() < 10)
    Serial.println(F("No GPS data received: check wiring"));
}

// This custom version of delay() ensures that the gps object
// is being "fed".
static void smartDelay(unsigned long ms)
{
  unsigned long start = millis();
  do 
  {
    while (ss.available())
      gps.encode(ss.read());
  } while (millis() - start < ms);
}

static void printFloat(float val, bool valid, int len, int prec)
{
  if (!valid)
  {
    while (len-- > 1)
      Serial.print('*');
    Serial.print(' ');
  }
  else
  {
    Serial.print(val, prec);
    int vi = abs((int)val);
    int flen = prec + (val < 0.0 ? 2 : 1); // . and -
    flen += vi >= 1000 ? 4 : vi >= 100 ? 3 : vi >= 10 ? 2 : 1;
    for (int i=flen; i<len; ++i)
      Serial.print(' ');
  }
  smartDelay(0);
}

static void printInt(unsigned long val, bool valid, int len)
{
  char sz[32] = "*****************";
  if (valid)
    sprintf(sz, "%ld", val);
  sz[len] = 0;
  for (int i=strlen(sz); i<len; ++i)
    sz[i] = ' ';
  if (len > 0) 
    sz[len-1] = ' ';
  Serial.print(sz);
  smartDelay(0);
}

static void printDateTime(TinyGPSDate &d, TinyGPSTime &t)
{
  if (!d.isValid())
  {
    Serial.print(F("********** "));
  }
  else
  {
    char sz[32];
    sprintf(sz, "%02d/%02d/%02d ", d.month(), d.day(), d.year());
    Serial.print(sz);
  }

  if (!t.isValid())
  {
    Serial.print(F("******** "));
  }
  else
  {
    char sz[32];
    sprintf(sz, "%02d:%02d:%02d ", t.hour(), t.minute(), t.second());
    Serial.print(sz);
  }

  printInt(d.age(), d.isValid(), 5);
  smartDelay(0);
}

static void printStr(const char *str, int len)
{
  int slen = strlen(str);
  for (int i=0; i<len; ++i)
    Serial.print(i<slen ? str[i] : ' ');
  smartDelay(0);
}

Serial is spitting out this for every update:

No GPS data received: check wiring

GPS is on, and can see based on the fix LED that satellite fix has occurred in both tests – no difference in output. Wires checked.
Maybe suboptimal pin solder job, but can't see that it should give no signal? 

EDIT: After suggestions, re-soldered pinheader – still nothing in the serial prompt on hardware serial (pin 0,1), software serial (pin 3,4) and TinyGPS++ throws the same error (pin 3-4 + 8-9). Double-checked RX/TX order.
A colleague found an old Ublox Neo 6-M GPS, I plugged it in and repeated the above with the same empty serial results, not sure what to make of this..


user37949: Accidentally fixed it when booting up the board tonight – not sure what changed but the serial prompt is on fire.
Wires: 5V - VIN, GND – GND, TX – 8, RX – 9
Code:
#include <SoftwareSerial.h>

// setup gps serial
int gpsTxPin = 8;
int gpsRxPin = 9;
SoftwareSerial gpsSerial(gpsTxPin, gpsRxPin);

void setup()
{
  Serial.begin(9600);  //set monitor to 9600

  gpsSerial.begin(9600); //adjust for GPS unit

  Serial.println("Ready!");
}

void loop()
{
  while(gpsSerial.available())
  {
    char c = gpsSerial.read();
    Serial.print(c);
  }
}

Excerpt from serial monitor:
...

$GPVTG,248.75,T,,M,0.19,N,0.35,K,A*3F
$GPGGA,231351.000,,,,,0,05,,,M,,M,,*7A
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,2,1,07,13,65,290,32,30,54,066,36,20,48,286,33,15,31,288,31*75

...


37949: <p>New <a href="https://www.adafruit.com/product/746" rel="nofollow noreferrer">Adafruit GPS</a> connected to my Arduino 101 board. </p>

<p>When trying to use the RX/TX hardware serial (on digital pins 0 / 1), with a simple sketch (described by Adafruit) to output a serial response, I'm not seing anything in the serial monitor (9600 baud).</p>

<pre class="lang-arduino prettyprint-override"><code>// this sketch will allow you to bypass the Atmega chip
// and connect the Ultimate GPS directly to the USB/Serial
// chip converter.

// Connect VIN to +5V
// Connect GND to Ground
// Connect GPS RX (data into GPS) to Digital 0
// Connect GPS TX (data out from GPS) to Digital 1

void setup() {}
void loop() {}
</code></pre>

<p>Wires connected as in the sketch, also tried swapping them out in case of faulty wire.</p>

<p>Went on to try TinyGPS++ default example code, across a variety of pins: 3,4 &amp; 8,9 &amp; 0,1. </p>

<pre class="lang-arduino prettyprint-override"><code>#include &lt;TinyGPS++.h&gt;
#include &lt;SoftwareSerial.h&gt;
/*
   This sample code demonstrates the normal use of a TinyGPS++ (TinyGPSPlus) object.
   It requires the use of SoftwareSerial, and assumes that you have a
   4800-baud serial GPS device hooked up on pins 4(rx) and 3(tx). EDITED BELOW.
*/

static const int RXPin = 8, TXPin = 9;
static const uint32_t GPSBaud = 9600;

// The TinyGPS++ object
TinyGPSPlus gps;

// The serial connection to the GPS device
SoftwareSerial ss(RXPin, TXPin);

void setup()
{
  Serial.begin(9600);
  ss.begin(GPSBaud);

  Serial.println(F("FullExample.ino"));
  Serial.println(F("An extensive example of many interesting TinyGPS++ features"));
  Serial.print(F("Testing TinyGPS++ library v. ")); Serial.println(TinyGPSPlus::libraryVersion());
  Serial.println(F("by Mikal Hart"));
  Serial.println();
  Serial.println(F("Sats HDOP Latitude   Longitude   Fix  Date       Time     Date Alt    Course Speed Card  Distance Course Card  Chars Sentences Checksum"));
  Serial.println(F("          (deg)      (deg)       Age                      Age  (m)    --- from GPS ----  ---- to London  ----  RX    RX        Fail"));
  Serial.println(F("---------------------------------------------------------------------------------------------------------------------------------------"));
}

void loop()
{
  static const double LONDON_LAT = 51.508131, LONDON_LON = -0.128002;

  printInt(gps.satellites.value(), gps.satellites.isValid(), 5);
  printInt(gps.hdop.value(), gps.hdop.isValid(), 5);
  printFloat(gps.location.lat(), gps.location.isValid(), 11, 6);
  printFloat(gps.location.lng(), gps.location.isValid(), 12, 6);
  printInt(gps.location.age(), gps.location.isValid(), 5);
  printDateTime(gps.date, gps.time);
  printFloat(gps.altitude.meters(), gps.altitude.isValid(), 7, 2);
  printFloat(gps.course.deg(), gps.course.isValid(), 7, 2);
  printFloat(gps.speed.kmph(), gps.speed.isValid(), 6, 2);
  printStr(gps.course.isValid() ? TinyGPSPlus::cardinal(gps.course.value()) : "*** ", 6);

  unsigned long distanceKmToLondon =
    (unsigned long)TinyGPSPlus::distanceBetween(
      gps.location.lat(),
      gps.location.lng(),
      LONDON_LAT, 
      LONDON_LON) / 1000;
  printInt(distanceKmToLondon, gps.location.isValid(), 9);

  double courseToLondon =
    TinyGPSPlus::courseTo(
      gps.location.lat(),
      gps.location.lng(),
      LONDON_LAT, 
      LONDON_LON);

  printFloat(courseToLondon, gps.location.isValid(), 7, 2);

  const char *cardinalToLondon = TinyGPSPlus::cardinal(courseToLondon);

  printStr(gps.location.isValid() ? cardinalToLondon : "*** ", 6);

  printInt(gps.charsProcessed(), true, 6);
  printInt(gps.sentencesWithFix(), true, 10);
  printInt(gps.failedChecksum(), true, 9);
  Serial.println();

  smartDelay(1000);

  if (millis() &gt; 5000 &amp;&amp; gps.charsProcessed() &lt; 10)
    Serial.println(F("No GPS data received: check wiring"));
}

// This custom version of delay() ensures that the gps object
// is being "fed".
static void smartDelay(unsigned long ms)
{
  unsigned long start = millis();
  do 
  {
    while (ss.available())
      gps.encode(ss.read());
  } while (millis() - start &lt; ms);
}

static void printFloat(float val, bool valid, int len, int prec)
{
  if (!valid)
  {
    while (len-- &gt; 1)
      Serial.print('*');
    Serial.print(' ');
  }
  else
  {
    Serial.print(val, prec);
    int vi = abs((int)val);
    int flen = prec + (val &lt; 0.0 ? 2 : 1); // . and -
    flen += vi &gt;= 1000 ? 4 : vi &gt;= 100 ? 3 : vi &gt;= 10 ? 2 : 1;
    for (int i=flen; i&lt;len; ++i)
      Serial.print(' ');
  }
  smartDelay(0);
}

static void printInt(unsigned long val, bool valid, int len)
{
  char sz[32] = "*****************";
  if (valid)
    sprintf(sz, "%ld", val);
  sz[len] = 0;
  for (int i=strlen(sz); i&lt;len; ++i)
    sz[i] = ' ';
  if (len &gt; 0) 
    sz[len-1] = ' ';
  Serial.print(sz);
  smartDelay(0);
}

static void printDateTime(TinyGPSDate &amp;d, TinyGPSTime &amp;t)
{
  if (!d.isValid())
  {
    Serial.print(F("********** "));
  }
  else
  {
    char sz[32];
    sprintf(sz, "%02d/%02d/%02d ", d.month(), d.day(), d.year());
    Serial.print(sz);
  }

  if (!t.isValid())
  {
    Serial.print(F("******** "));
  }
  else
  {
    char sz[32];
    sprintf(sz, "%02d:%02d:%02d ", t.hour(), t.minute(), t.second());
    Serial.print(sz);
  }

  printInt(d.age(), d.isValid(), 5);
  smartDelay(0);
}

static void printStr(const char *str, int len)
{
  int slen = strlen(str);
  for (int i=0; i&lt;len; ++i)
    Serial.print(i&lt;slen ? str[i] : ' ');
  smartDelay(0);
}
</code></pre>

<p>Serial is spitting out this for every update:</p>

<blockquote>
  <p>No GPS data received: check wiring</p>
</blockquote>

<p>GPS is on, and can see based on the fix LED that satellite fix has occurred in both tests – no difference in output. Wires checked.</p>

<p>Maybe suboptimal pin solder job, but can't see that it should give no signal? </p>

<p><a href="https://i.stack.imgur.com/15y3s.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/15y3s.jpg" alt="Solder job"></a></p>

<p>EDIT: After suggestions, re-soldered pinheader – still nothing in the serial prompt on hardware serial (pin 0,1), software serial (pin 3,4) and TinyGPS++ throws the same error (pin 3-4 + 8-9). Double-checked RX/TX order.</p>

<p>A colleague found an old <a href="https://www.u-blox.com/en/product/neo-6-series" rel="nofollow noreferrer">Ublox Neo 6-M GPS</a>, I plugged it in and repeated the above with the same empty serial results, not sure what to make of this..</p>

<p><a href="https://i.stack.imgur.com/4OBUl.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4OBUl.jpg" alt="enter image description here"></a></p>
 37949: <p>Accidentally fixed it when booting up the board tonight – not sure what changed but the serial prompt is on fire.</p>

<p>Wires: 5V - VIN, GND – GND, TX – 8, RX – 9</p>

<p><strong>Code:</strong></p>

<pre class="lang-arduino prettyprint-override"><code>#include &lt;SoftwareSerial.h&gt;

// setup gps serial
int gpsTxPin = 8;
int gpsRxPin = 9;
SoftwareSerial gpsSerial(gpsTxPin, gpsRxPin);

void setup()
{
  Serial.begin(9600);  //set monitor to 9600

  gpsSerial.begin(9600); //adjust for GPS unit

  Serial.println("Ready!");
}

void loop()
{
  while(gpsSerial.available())
  {
    char c = gpsSerial.read();
    Serial.print(c);
  }
}
</code></pre>

<p><strong>Excerpt from serial monitor:</strong></p>

<pre class="lang-none prettyprint-override"><code>...

$GPVTG,248.75,T,,M,0.19,N,0.35,K,A*3F
$GPGGA,231351.000,,,,,0,05,,,M,,M,,*7A
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,2,1,07,13,65,290,32,30,54,066,36,20,48,286,33,15,31,288,31*75

...
</code></pre>
