Faint Alarm with No Lights - Yanmar 3ym30

[j5th]

Hi All, I am having a hell of a time diagnosing this alarm that started to go off. Engine runs fine but I am worried to run it for long. 2015 Yanmar 3YM30e with B20 control panel with 510 hours.. Batteries seem fine and the alternator seems to be charging the batteries. Coolant level is just above Low on the reservoir.

After I power on the display all warning lights function properly, however, when I start the engine the loud alarm and the warning lights go OFF but there is another alarm that's 1/2 the loudness with no warning lights that continues to go off. I have no clue what the alarm is coming from

I'm going to replace the oil switch but I doubt that is the issue.. The mechanic I hired was absolutely useless. Any ideas?

Here is a video that should help explain: https://youtu.be/cR3MNnaKxfQ

[GordMay]

Greetings and welcome aboard the CF, j5th.

☞ http://jeanneau349.com/index_htm_fil...ol%20Panel.pdf

[JoeRobertJr]

In the video, it sounded like the faint alarm started as soon as you turned on the power panel, even before the loud alarm sounded. Did I hear that correctly?
Is the faint alarm definitely coming from the same speaker that makes the loud alarm, not some other system nearby?

[mike d.]

I would check your tach circuit! The tach needle moved when you hit the 1st button, jumped a bit, and when the needle pinned at 0 the 1st alarm went off, before you hit the start button!

[atoll]

i would check fanbelt tension,if the belt is slipping slightly this can lead to the field circuit being slow to excite the alternator,try revving the engine above 1500 rpm.
if the alarm stops belt tension is probably the problem

[sainted]

Something similar happened to me whilst on a passage. Essentially, water got on/in the panel and provided a high resistance path to ground for the alarm buzzer. It made me so crazy I eventually had to cut the power wire to the alarm.

Anywho, it sounded much like it does in your video.

Fair winds!

[j5th]

Originally Posted by JoeRobertJr

In the video, it sounded like the faint alarm started as soon as you turned on the power panel, even before the loud alarm sounded. Did I hear that correctly?
Is the faint alarm definitely coming from the same speaker that makes the loud alarm, not some other system nearby?

Yes exactly, very observant as I didn't even notice that till you said it! The alarm starts to sound the second I turn it on, then you can hear the normal alarm kick in after a few seconds. I am going to take the control panel out today so I can hear it better as it might even be coming from the bow thruster control. I should also mention, when I turn off the engine you can hear the alarm slowly fade away almost like a capacitor acts.

I just replaced my AGM battery that warped so bad and the sound may have started after I did that. I was advised to unplug the oil switch relay and plug it back in to potentially reset it.

Also just got the new oil switch that i'll replace but I doubt that will solve it.

I will also check belt tension, alternator output, and water behind the panel and report back today. I'm not sure how to test the tach circuit but I might be able to find instructions.

We are trying to go on a little family outting tomorrow for Thanksgiving and I just want to make sure I will not cause any damage to the engine from low oil pressure, but you'd think that oil switch light would be screaming if that was the issue.

Thanks everyone for your suggestions, I really appreciate it!

[GordMay]

Originally Posted by j5th

... We are trying to go on a little family outting tomorrow for Thanksgiving and I just want to make sure I will not cause any damage to the engine from low oil pressure, but you'd think that oil switch light would be screaming if that was the issue.
Thanks everyone for your suggestions, I really appreciate it!

Check your oil level, with the dipstick.

[j5th]

Originally Posted by GordMay

Check your oil level, with the dipstick.

Oil level is perfect using the dipstick. Just replaced it about 20 engine hours ago. Even so, I wonder if the oil pump isn't working, but that should not cause this type of alarm buzzer. I assume the oil switch would be lighting up for low oil pressure if that was the case. Do you happen to know how I can make 100% sure oil is flowing? I was thinking about taking the valve cover off, cut the fuel and try cranking to see if the oil is pumping.

[Squanderbucks]

Engine warning buzzers -alarms are not varying intensity. If your alarm is faint the you not only have the original causing issue to correct but a defective alarm circuit. Most often the feason for the faint alarm is corrosion on the wire connectors or an almost broken wire. Leek further. Ron a new wire to the buzzer and see how loud it is supposed to be.

[ramblinrod]

Originally Posted by j5th

Hi All, I am having a hell of a time diagnosing this alarm that started to go off. Engine runs fine but I am worried to run it for long. 2015 Yanmar 3YM30e with B20 control panel with 510 hours.. Batteries seem fine and the alternator seems to be charging the batteries. Coolant level is just above Low on the reservoir.

After I power on the display all warning lights function properly, however, when I start the engine the loud alarm and the warning lights go OFF but there is another alarm that's 1/2 the loudness with no warning lights that continues to go off. I have no clue what the alarm is coming from

I'm going to replace the oil switch but I doubt that is the issue.. The mechanic I hired was absolutely useless. Any ideas?

Here is a video that should help explain: https://youtu.be/cR3MNnaKxfQ

Check the connection between panel and engine wiring harness for corrosion.

[j5th]

UPDATE

after pulling off the Yanmar control panel I found out the alarm was not coming from the control panel buzzer! It was coming from the adjacent Quick Bow Thruster Controller! This is so odd because there should be no reason the alarm is going off for the bow thruster because it was not even turned on. The dedicated 2 AGM's battery voltage is fine as well. Bow Thruster works as normal.

The manual was no help and Quick is not returning my emails
Here is a video: https://youtu.be/UQhXRXDTGjU

[JoeRobertJr]

Interesting!
Question: Are you certain the sound was coming from the bow thruster contoller itself? Could it be coming from something else in there and just got louder as you pulled the unit out because the sound can now come through the hole? I could not tell from the video.
Does your model bow thruster include a warning alarm for low voltage at the control unit? Or some sort of reminder alarm that is supposed to go off only if left on for a long time?
Does it still only alarm while the engine controller is On? I would guess voltage at the bow thruster contoller is the only way the engine controller can have an effect. For example, if their positive wires are connected to the same point, and the engine controller is bringing down the voltage that the thruster controller sees.
For the sake of isolating the cause, I would be tempted to disconnect the positive wire from the thruster controller to confirm that is the source of the alarm. Then, with the thruster controller reconnected, watch the voltage as you turn the engine controller on and off.

[j5th]

Originally Posted by JoeRobertJr

Interesting!
Question: Are you certain the sound was coming from the bow thruster contoller itself? Could it be coming from something else in there and just got louder as you pulled the unit out because the sound can now come through the hole? I could not tell from the video.
Does your model bow thruster include a warning alarm for low voltage at the control unit? Or some sort of reminder alarm that is supposed to go off only if left on for a long time?
Does it still only alarm while the engine controller is On? I would guess voltage at the bow thruster contoller is the only way the engine controller can have an effect. For example, if their positive wires are connected to the same point, and the engine controller is bringing down the voltage that the thruster controller sees.
For the sake of isolating the cause, I would be tempted to disconnect the positive wire from the thruster controller to confirm that is the source of the alarm. Then, with the thruster controller reconnected, watch the voltage as you turn the engine controller on and off.

Yes I am certain the alarm is coming from the bow thruster controller. Sorry I didn't show it in the video but I pulled it out and there is an alarm on the back that I can cover with my finger and it gets more silent. I also disconnected the controller and the alarm stops. That is how I maintained my sanity last week when I took it out for a sail

The manual states the insufficient voltage alarm will only activate with the bow thruster enabled and is below 10.5V. The 2 AGM's are reading 13.3V so I don't think that is technically the issue. There is also an LED flash pattern that is supposed to happen if there is a problem, however, the LEDs on the control unit are a steady green blink like normal until I activate the controller, then it's steady green as normal during operation. Also, the box on the bow thruster itself has an "ERR" LED that is off as normal.

The alarm immediately activates when I turn the engine control on and will not turn off until I turn off the engine control. As you mentioned the engine control power must be having some effect on the bow thruster control. I will try your idea of reading the voltage at the controller. If the bow thruster itself has adequate power but the voltage reading at the controller is low that might be an explanation.

I was investigating under my v-berth and I found the previous owner must have done some bad electrical work because There is an alligator clipped jumper cable in between two connections and it happens to be connected to the same terminal block the bow thruster gets power from. I'll take a picture and fix the wiring to see if this is the issue. I guess it could be a faulty controller alarm but I doubt it because my boat is a '15

I am so annoyed because just took it out last week all of the sudden my B&G Zeus T7 cannot see anything else on the network including depth, autopilot, and music server. The secondary slave unit see's depth fine but has no option to enable autopilot. Hopefully B&G has better support than Quick

[JoeRobertJr]

Thanks for the update. The troubleshooting steps you are taking are exactly what I would do. That alligator clip does sounds suspicious. Make me wonder if that was done to provide an additional current path to the terminal block to reduce the voltage drop. Anyway, it sounds like you have some decent clues to work with. Good luck!