Troubleshoot tricks for Focal 903

Troubleshoot Focal 903

I recommend before you start reading this post please read the post about basic Information of Focal 903.

I will first start with surface unit as this unit is easily accessible to techs and discuss various LED's and indicator and their use while troubleshooting.


Fuse-There is a 1 Amp fuse at the back of this unit and if you are running on fluctuating power supply this is the only protection this unit has so if this unit is not turning on,Please check this fuse.

Power Supply Indicator-The Power supply module has 3 LED's on it which displays three out put voltages of power supply,As this unit comes with different types of power supply depending on model and requirement but most commonly used one is the one with 240 V input supply and output of +12v,-12v,+5v and you can check the output by looking at the glowing led's.

Note-Power supply for focal unit can be operated on 120v or 240v,Some power supply models comes with auto selector function while some power supply has manual switch in it to select the voltage and to access this switch you need to open power supply cover.

Tx and Rx LED's on data channel-This is my favorite as from this you can tell which side of focal 903 has problem.

When telemetry is working fine both RED and GREEN led's will blink continuously telling you that focal is receiving and transmitting data.

In surface focal unit RED led represents local computer and Green led represents remote computer(POD),So if your green led is blinking and red is not,This condition represents that pod is sending data but computer in control van has problem.

This logic applies for both surface and Subsea unit as for subsea unit POD will become local computer and control van computer will become remote computer and logic will remain the same

RED LOCAL -GREEN REMOTE

So just by looking at these led's a technician can tell which part has problem surface or subsea.

Note-These LED's should be blinking and not solid on, As blinking led represents data transfer and some systems have high data rate and led blinks at such a fast rate that led appears to be solid, so watch it carefully.

LINK LED-Link LED represents that focal unit is receiving enough optical power from other end and fiber is GOOD but this does not represents that telemetry is working.

Diagnostic Port-There is a separate post about using focal 903 diagnostic port,Please refer to that post.

Video Signal-when focal receives a video signal led related to that particular channel will blink and indicates video signal is being received.

How to test daughter card on AIB backplane-Take a Fluke multimeter(Only fluke) and select diode mode place black lead on the bottom most pin and red lead on the second pin (Last two pins) and red led will glow and indicates daughter card is working fine.


Note-This is only applicable  for RS-232 data card.

If daughter card has gone bad you need to replace it,Please make sure you take precautions while handling cards as daughter boards are sensitive towards electrostatic interference.

Note-when replacing daughter card on AIB module please align the white dot on card as well as on backplane as daughter card can be fitted both ways.

Now Lets talk about Subsea unit

Subsea unit has a 3Amp fuse on back plane and when this fuse blows and you don't have spare one no need to worry,Open backplane and there will be another fuse fitted as SPARE fuse.

Link LED and Video led's have same function as on top unit.the only difference you will find that the subsea unit is a high density unit,Hence smaller in size.