RS125 - NO FIX being reported on Pathfinder Series Display or Multifunction Display

[Chuck - Raymarine - Moderator]

RS125 - NO FIX being reported on Pathfinder Series Display or Multifunction Display

Raymarine's Raystar 125 GPS Sensor (RS125) was produced to satisfy the external GPS data source requirements of Raymarine products requiring GPS data (lat, lon, COG, SOG, FIX Status, etc.) from external device. The RS125 GPS sensor can be wired for use as a SeaTalk or NMEA 0183 device.

Before beginning diagnostics, verify the following:
1) that the problem can be reproduced at the time of this diagnostic;
2) that the boat's batteries are fully charged or that you are connected to shore power;
3) if you have more than 5 SeaTalk devices, it is recommended that a second power insertion point be added after the last SeaTalk device to ensure adequate sufficient power to the SeaTalk network.

The following diagnostic can be used to troubleshoot a NO FIX condition for the RS125 installed as a SeaTalk device (most common). Verify the following:
- verify that the GPS is installed such that it has a clear view of the horizon and is not installed below any hard surfaces
- verify that the GPS is not installed within 3' of a radar scanner (if mounted within its beam angle) or VHF antenna
- check the status LED atop the RS125:
----- Not illuminated: the device is not powered or suffered a total failure
----- Flashing RED: the unit is booting up, its software is being upgraded, or is unable to boot
----- Flashing ORANGE: the unit is running, but does not have a FIX
----- Flashing GREEN: the unit is running and has a fix
- ensure proper connections by unplugging RS125’s cable from the sensor’s shell and checking the following with an analog voltmeter (Note: the RS125's power/data cable is removed by rotating the GPS Sensor's power/data cable plug's locking ring in a counter clockwise direction. The pin numbers referenced in the below are assigned in a clockwise orientation from the plug's indexing groove (pin to right of indexing groove is pin 1)) :
----- Between pin 1 and 2: +12VDC
----- Between pin 1 and 3: +12VDC
----- Between pin 5 and 2: +12VDC
----- Between pin 4 and 2: fluctuating +9 to +11VDC if connected to a powered SeaTalk device.

----- Note: it is recommended that the RS125 be powered by the SeaTalk bus (if the vessel is so equipped) or a switched +12VDC source rather than from the Multifunction Display’s red SeaTalk lead.

- cycle power to the RS125 (verify that the power as measured between pins 1 and 2 drops to zero). This will force the GPS to reset. If the GPS acquires satellites and a FIX afterwards, the nothing more need be done.
- if pole mounted, ensure that the pole mount provided with the RS125 is not filled with water.

The pin out for the RS125 cable's plug is as follows when looking at the face of the plug moving clockwise from the plug's indexing keyway:
- pin 1: red
- pin 2: black or shield
- pin 3: yellow
- pin 4: brown
- pin 5: green

A depleted memory battery within the Raystar 125 GPS Sensor will result in cold start symptoms (slow GPS FIX acquisition), inability to acquire a GPS position FIX (i.e. the RS125's Status LED is flashing amber), or high HDOP. Also, should one have a problematic Raystar 125 GPS Sensor, then replacement of its battery is an inexpensive means of possibly restoring operation of the sensor. The Raystar 125 GPS Sensor is supplied with a standard CR2032 battery within its battery slot. When the upper shell and base of the Raystar 125 GPS Sensor are separated, you will find an o-ring which seals the sensor. Simply ensure that the o-ring remains in place when reassembling the sensor. Also, separating the base from the sensor's upper shell will also break the metallic paste seal between the processor board and the upper shell. Breaking this seal may reduce the sensitivity of the sensor, but cannot be avoided if the sensor's battery will be replaced. Feedback from customers who have performed replacement of this battery has been good and has not included any reports of reduced sensitivity of the sensor when put back into service.


RAYFAQ#