[CA] [CA11] Smart Pilot melted 2A fuse, blown board

[rickgard]

hello Raymarine forum
I have a 2007 Ray system which has performed flawlessly until I powered it up for the first time after winter lay-up. e80s work, Raystar works, radio, depth are good- but the st8002 pilot screen was blank. Further investigation of the Smart Pilot found the 2A SeaTalk fuse melted to the board and at least 25% of the components near the fuse burned completely away.

I found a used Smart Pilot S1 to replace the blown unit but before I replace it I want to know that I won't blow the replacement as well. I would grateful to know what to check and where.

My system:
two e80 (one connected to radar, one running the chart chips)
st8002 pilot head
Smart Pilot S1
rudder indicator, fluxgate, linear drive
Raystar gps

the e80s are working, but don't receive GPS fix, nor do they receive Rudder Position data for a data box.
the pilot head is blank, seemingly no power.

If I disconnect the SeaTalk 3 pin cable from the Pilot head then the e80s get GPS fix and operate as usual. still no Rudder position data in the e80 databox.

Reconnecting the SeaTalk cable at the pilot head, then check what is coming to the Smart Pilot SeaTalk Red/Yellow/Shield pins from the pilot head and found:

SeaTalk red to SeaTalk shield = 0v
SeaTalk red to ship's ground = 0v
SeaTalk red to SeaTalk yellow = 11.7v

SeaTalk yellow to SeaTalk shell 11.7v
SeaTalk yellow to ship's ground= 11.69v

SeaTalk shield to ship's ground = 0v

the SeaTalk red was connected to the terminal on the Smart Pilot - I mention this because reading through posts on the forums I found that should not be the case when the smart pilot is powered. My e80s, VHF, Raystar are all powered on one breaker, and the autopilot is powered on a separate breaker.

the pilot head SeaTalk cable input does include spliced wires from one e80. I guess this supplies data bidirectionally for the follow function as well as supplying the Raystar data.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Rick,

Q. the SeaTalk red was connected to the terminal on the Smart Pilot - I mention this because reading through posts on the forums I found that should not be the case when the smart pilot is powered. My e80s, VHF, Raystar are all powered on one breaker, and the autopilot is powered on a separate breaker.

A. In fact in the era of the E-Series Class MFDs and SmartPilot, it was common for the autopilot to supply power to the SeaTalk bus within small systems such as this. Unlike the MFD designs with followed, the SeaTalk port of the C/E-Series Classic MFDs was capable of powering a small SeaTalk bus which was basically limited to a powering a GPS sensor. However, within systems featuring additional SeaTalk devices, it was recommended that this feature not be used and the the red lead of the MFD's SeaTalk/Alarm Cable not be connected to the SeaTalk bus. It appears that this was an oversight within your system, as it appears that your MFD is indeed powering the GPS sensor via the MFD's SeaTalk/Alarm Cable.

Regarding the autopilot, it is clear from your description that the autopilot course computer, and possibly the autopilot control head have suffered a failure of their communications circuitry. However, without having a technician inspect and test these items, it would not be possible to know the extent of the damage. Unfortunately, Raymarine can no longer service these autopilots. Your idea concerning replacement of the autopilot course computer is indeed one option which may be undertaken. However, in doing so, the entire course computer should be swapped out rather than attempting to repair the original. That said, if the autopilot control head has also suffered a failure (I would recommend testing it alone with the replacement course computer), then you may want to consider replacing the autopilot with an Evolution autopilot.

[rickgard]

thanks very much, Chuck.
I will remove and inspect the autopilot control head too.

I am replacing the entire course computer; the surge must've been spectacular since it burned most of the computer. And this is what concerns me now - Is it possible for this to happen again? as I originally posted I am finding voltages no higher than 11.7V coming to the old course computer. Are there specifications available for what I should find in the SeaTalk network? How can I tell if there is some path shorted?

[Chuck - Raymarine - Moderator]

Rick,

The 2A fuse is responsible for powering the SeaTalk bus. The most common causes for such failures would be a lightning strike or wiring problem. If you are uncertain how to go about troubleshooting a short circuit, then it would be recommended that a Certified Raymarine Installer be contacted to visit the boat. The following voltages should typically be observed within a properly functioning SeaTalk bus within which communications are occurring (recommend using a common analog voltmeter / multimeter):
- SeaTalk power (red) to SeaTalk ground (shield): +12 VDC
- SeaTalk data (yellow) to SeaTalk ground (shield): pulsing +9 VDC to +12 VDC

[rickgard]

thanks for the quick replies, Chuck.
I'll be on the boat with multimeter in hand!

[Chuck - Raymarine - Moderator]

You're welcome.

[rickgard]

I found the break in a yellow ST wire! likely ground out the first time I powered the boat up.

Dear Chuck,
I have tested the following throughout the system to the boat ground:
Boat is 13.45V
Red SeaTalk = 12.65v
yellow pulses = 9.3v - 10.25 - 12.6v
shield is 0

I also checked continuity of the yellow from the termination at the course computer to and through the ST8002 head and to both e80 MFDs. also the red and shield.

without breaking into the ST8002 head I can't see that it is damaged. I can get continuity from its yellow/red/gnd tabs - so it is not burned to [censored] like the course computer. would this be an indication that the control head is still good?

I ask because I fear connecting my new(used) course computer even though all the voltages seem to behave as expected in the various points of the SeaTalk bus.

thank you very much for your help so far. It was great to find the break in the yellow!

[Chuck - Raymarine - Moderator]

Rick,

To test the autopilot control head, simply connect one end of a SeaTalk cable to a 12 VDC circuit which has been protected with a 5A fuse. Verify that the autopilot control head powers up. If not, it has suffered a failure and will need to be replaced (ST6xxx/ST7xxx/ST8xxx autopilot control heads can no longer be serviced). Should the autopilot control head power up, then use an analog voltmeter to measure voltage across data (yellow) and ground (shield) SeaTalk leads. Again, as the buttons are pressed, you should see a change in the measured voltage to then see similar pulsing of the meter's needle in the voltage range specified within my last response. Should such pulsing not be observed, then the autopilot control head would be deemed to have suffered a failure and will need to be replaced. ST6xxx/ST7xxx/ST8xxx autopilot control heads which are interfaced to a S1/S1G/S2/S2G/S3/S3G/150/400 autopilot course computer may be replaced with your choice of a currently manufactured p70S or p70RS autopilot control head.

[rickgard]

I am very grateful for your clear help, Chuck.

Also glad to hear I can use a new P70 if needed.

[Chuck - Raymarine - Moderator]

You're welcome.