Electrics, at a distance, all help appreciated.

[IanCC]

A friend is in between Labrador and Greenland. Inconvenient electrical problem.

Charging light staying on, occasionally, when electrics switched off at engine control panel and sometime glows slightly when engine running. Occasional buzzing behind panel when electrics switched off at panel.

All stops when main battery switch put to off. Batteries charge fine. Can start and stop engine fine at present and can do without panel i believe.

Engine is Perkins M65. Control panel is by Sabre, bought by Perkins, Perkins can't help.

I need to take parts to fix this next week. I would very much appreciate others thinking this through as well.

Seems to me it is most probably the on/off/stop switch that is at fault. Yet when you look behind the panel the switch is doing a lot of work. Can't make out if it is a single pole(3 lugs) or double pole (6 lugs). See close up picture. Is that a resistor in there? starts to be above my pay grade at that point.

Wiring diagram shows a resistor by passing warning lamp. Could it be that? Not a hundred percent sure wiring diagram is 100% accurate.

All input very much appreciated.

Ian

 

[Alex_Blackwood]

A friend is in between Labrador and Greenland. Inconvenient electrical problem.

Charging light staying on when electrics switched off at engine control panel and sometime glows slightly when engine running. Occasional buzzing behind panel when electrics switched off at panel.

All stops when main battery switch put to off. Batteries charge fine. Can start and stop engine fine at present and can do without panel i believe.

Engine is Perkins M65. Control panel is by Sabre, bought by Perkins, Perkins can't help.

I need to take parts to fix this next week. I would very much appreciate others thinking this through as well.

Seems to me it is most probably the on/off/stop switch that is at fault. Yet when you look behind the panel the switch is doing a lot of work. Can't make out if it is a single pole(3 lugs) or double pole (6 lugs). See close up picture. Is that a resistor in there? starts to be above my pay grade at that point.

Wiring diagram shows a resistor by passing warning lamp. Could it be that? Not a hundred percent sure wiring diagram is 100% accurate.

All input very much appreciated.

Ian

I am sorry but really can't help, any thoughts would be pure guesswork and speculation. It really needs on site investigation. That black device with the silver band in the middle picture looks like a diode, not a resistor. Don't dive in and rip everything apart. Try one thing at a time, see if anything makes a difference. There are two diodes for the oil and water alarms at the top of one of the drawings. Just possible there could be a fault there, maybe! try those first, disconnect each in turn. If you are going to be fault finding for any time make sure you can recharge the batteries.
sorry can't be more helpful. Let us know how it goes, May not do any harm to take a new switch anyway. Shame you cannot ID the diodes. But a couple of spares of almost any size above an amp or so may be an idea.

 

[IanCC]

I am sorry but really can't help, any thoughts would be pure guesswork and speculation. It really needs on site investigation. That black device with the silver band in the middle picture looks like a diode, not a resistor. Don't dive in and rip everything apart. Try one thing at a time, see if anything makes a difference. There are two diodes for the oil and water alarms at the top of one of the drawings. Just possible there could be a fault there, maybe! try those first, disconnect each in turn. If you are going to be fault finding for any time make sure you can recharge the batteries.
sorry can't be more helpful. Let us know how it goes, May not do any harm to take a new switch anyway. Shame you cannot ID the diodes. But a couple of spares of almost any size above an amp or so may be an idea.

Thanks, maybe, i need a list of stuff to take. Wondering if that includes a new alternator.

 

[Alex_Blackwood]

Thanks, maybe, i need a list of stuff to take. Wondering if that includes a new alternator.

Don't think it is that desperate and as far as I can see from the drawing the switch is single pole. Think simple! What ever is wrong is not catastrophic.

 

[IanCC]

Bump

 

[wonkywinch]

Shame you cannot ID the diodes

Since they only drive indicator lamps, the ubiquitous IN4001 will work. (50v 1A).

 

[RunAgroundHard]

Perkins 4236, my lamp glows, partially fades in and out, flickers, if belt is slipping. Has also glowed when connections to ignition switch were dodgy.

 

[PaulRainbow]

I doubt very much that it's the diodes, they are so the buzzer sounds for different faults, but only the relevant light comes on. Also doubt it's the switch. I'd suspect the alternator.

 

[IanCC]

I doubt very much that it's the diodes, they are so the buzzer sounds for different faults, but only the relevant light comes on. Also doubt it's the switch. I'd suspect the alternator.

Thanks Paul.
Can you talk me through that please?
I don't understand how the warning lamp can be on when engine off and electrics switched off.
I am at the limit of my knowledge here, but my understanding is that the light is lit when there is a voltage difference. So engine off, switch on electric, power to alternator so lamp goes on. Engine starts, alternator produces voltage balancing that from switch so light goes out. If that is correct:

Engine off , alternator stopped, no current. Switch off, no current. How does light come on?

Really appreciate input.

Ian

 

[billskip]

I'd suspect the alternator.

Me too, brushes possibly...

 

[Alex_Blackwood]

Thanks Paul.
Can you talk me through that please?
I don't understand how the warning lamp can be on when engine off and electrics switched off.
I am at the limit of my knowledge here, but my understanding is that the light is lit when there is a voltage difference. So engine off, switch on electric, power to alternator so lamp goes on. Engine starts, alternator produces voltage balancing that from switch so light goes out. If that is correct:

Engine off , alternator stopped, no current. Switch off, no current. How does light come on?

Really appreciate input.

Ian

Have you any idea what the buzzing , with power off, is that you mention in your OP? Perhaps it is a clue.

 

[MontyMariner]

In my experience, weird faults like this are often caused by a poor 'earth' / return path connection.

 

[IanCC]

Have you any idea what the buzzing , with power off, is that you mention in your OP? Perhaps it is a clue.

No, unfortunately. Email not working terribly well at present. Have asked if it is a 'buzzer' buzzing or a faulty electric type buzz? No reponse as yet but suspect the latter because he said the buzzing noise had only happened once.

 

[Boater Sam]

If it is a resistor across the ignition warning lamp, it is to increase the exciter current on the alternator, its not your problem.
Your oil pressure and water temperature warning lights/alarm are probably controlled by diode logic to stop them affecting one another. I cannot read your circuit diagrams as the definition is too poor. Check those diodes, 1N4001 or any last number up to 7 will be suitable.
Most glowing charge indicator lamps are due to a poor high resistance connection somewhere, worse when they use LEDs.
Temporally disconnect the oil and water sensors and see if it makes any difference.
With all turned off you may be getting a feedback to the panel via the alternator which probably has its output on B+ connected to the starter motor and hence the battery. It could indicate diode failure/s in the alternator.
You are correct about the warning light. With ignition turned on it has a + feed to one side, starting the engine puts another + feed to the other side hence no current flows and the light goes off. So any bad connection or switch contact on either side can cause a glow.

 

[IanCC]

If it is a resistor across the ignition warning lamp, it is to increase the exciter current on the alternator, its not your problem.
Your oil pressure and water temperature warning lights/alarm are probably controlled by diode logic to stop them affecting one another. I cannot read your circuit diagrams as the definition is too poor. Check those diodes, 1N4001 or any last number up to 7 will be suitable.
Most glowing charge indicator lamps are due to a poor high resistance connection somewhere, worse when they use LEDs.
Temporally disconnect the oil and water sensors and see if it makes any difference.
With all turned off you may be getting a feedback to the panel via the alternator which probably has its output on B+ connected to the starter motor and hence the battery. It could indicate diode failure/s in the alternator.
You are correct about the warning light. With ignition turned on it has a + feed to one side, starting the engine puts another + feed to the other side hence no current flows and the light goes off. So any bad connection or switch contact on either side can cause a glow.

Thanks for that, really informative.

So if there is a faulty diode in the alternator allowing current to pass through to warning light when electric is switched off. Is there a serious problem? The battery drain from one 3w, or so, bulb isn't going to drain the batteries when they are being closely monitored. Or am i missing something enormous?

Do you think that could cause the dimly glowing or flickering warning light when engine is running?

Thanks again.
Ian

 

[IanCC]

Me too, brushes possibly...

Thanks , but why would the brushes cause the warning lamp to be on when engine and electric switched off?

 

[billskip]

Thanks , but why would the brushes cause the warning lamp to be on when engine and electric switched off?

you say

and sometime glows slightly when engine running.

Which can be caused by worn brushes...
In 65years messing about with these things I've only ever once had diode failure, and that was not intermittent,it was good or it was dud no half measure. regulator, bearings brushes and electrical "leakage" to ground though dirt moisture etc are the usual suspects.
It of course could be something as simple, as said, a poor connection or loose belt, but if the alternator has never been serviced it's giving a good indication its due for one....
But it's only my two penny worth...I like you and others here are working with guess work, on site with a meter will quickly diagnose the problem.