ST4000 MK1 not powering up

[patrickkidd]

Hello! I have an old black ST4000 MK1 and the unit only powers up every 10th-15th flip of the power switch. The unit came with the boat which I bought last year.

I bought an identical replacement control unit on eBay because the display of my original was also dying, and found that it did the same thing. On each flip of the switch where it didn't turn on, the speaker sent out a constant tone, the display was blank, and the motor would turn until it reached the end of it's travel. On each successful flip of the switch the speaker would beep once and the display would turn on. Now the speaker has stopped making sound at all and I have to jump into the cockpit to see if the display is on after each switch - quite cumbersome.

If my power source and wiring is good, is this a known issue on older units? Is there something else I can do?

Thanks!

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Partrick

It is recommended the vessel be connected to shore power, that its batteries be permitted to fully charge. After doing so and while still connected to shore power that the pilot be tested again. Should the problem persist when so tested, then it is recommended that the voltage level be monitored at the ST4000+ wheel pilot's power terminals when the problem occurs. Should the measured voltage remain within the autopilot's operating range, then it would appear that the pilot has suffered a failure. If seeking additional guidance, then please respond with information regarding measured voltage level before and after the pilot was switched ON.

[Bikerbob]

Have you run the unit off a seperate known good battery off of the boat? Power up just the head(display) first.. it should go to the ST4000 display with your beep then the C234 deg or whatever.. Then add the flux gate and finally the drive unit.. if your problem cannot be repeated then its a boat issue..
I know my issue is wiring as I cannot get it to happen on a clean battery off the boat.

Good luck.

James