Okay all of you electrical gurus here is a good one for you to de-cipher.
Yesterday as I was leaving the boat I noticed a strange occurrence in the stereo, but paid little attention to it. Then as I was shutting the down the boat, I noticed that the pilot lignt on the distribution panel was out, so I thought no biggie I have spares. However, as I investigated further, I noticed that the cabin lights weren’t working.
So now, I lock up the boat and head home. Today, I pulled the panel and began testing the breakers. Well as luck would have it I broke the breaker for the Cabin Lights, but that is not the problem. I have two 12v cigarette plug-ins and even though the breaker is out of the panel, IF I have any breaker in the on position, I can control fans that are plugged into the 12v plugs buy using the switches on the lights (and the lights don’t work).
If I turn on the battery switch, the pilot light does not work, but IF I turn on a cabin light (did I mention they don’t work) the pilot light comes on! I am very perplexed! One possible solution offered up by the marina guys is that somehow, the positive side is feeding back through the ground!
I know that this is very difficult to understand I (let alone explain) in this medium, but if you have any idea of what I need to do let me know!
Thanks and have a wonderful FREEDOM DAY! Happy Fire Crackers.
Poltergeist in the DC System
Moderator: bobdugan
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barfwinkle
- Posts: 2169
- Joined: Feb 6th, '05, 10:34
- Location: S/V Rhapsody CD25D
Poltergeist in the DC System
Bill Member #250.
Poltergeist
Sounds like a missing ground. Perhaps the cabin lights are supplying a ground to the system when they are turned on. (One side of the lights are grounded) Another reason this could be is because the pilot lamp has only two connections, power and ground. If the ground is missing it won't light. The grounds on my 22d all go to a ground plate in the bilge. You would need an ohmeter to troubleshoot a missing ground. Charles.
Try isolation
I think if I were trying to find this problem I would go to the power distribution panel and one by one remove a circuit until the problem goes away.
Then, one by one reconnect each circuit until the problem reappears.
Then, leave the guilty circuit aside, and reinstall the rest, one by one testing as you go.
Hopefully you will find one circuit causing the problem. You can either trouble shoot the circuit or just rerun the wire for that circuit.
To trouble shoot, you can attach a meter to the circuit and remove everything from the circuit. The circuit should read open, if it doesn't you probably will need to run a new wire to everything on that circuit.
If it reads open, then, one by one start reinstalling the fixtures, testing as you go.
I don't spend a lot of time trouble shooting a circuit. I prefer to just run a new wire and I know the problem is gone and will not return.
Good luck
Gary
Then, one by one reconnect each circuit until the problem reappears.
Then, leave the guilty circuit aside, and reinstall the rest, one by one testing as you go.
Hopefully you will find one circuit causing the problem. You can either trouble shoot the circuit or just rerun the wire for that circuit.
To trouble shoot, you can attach a meter to the circuit and remove everything from the circuit. The circuit should read open, if it doesn't you probably will need to run a new wire to everything on that circuit.
If it reads open, then, one by one start reinstalling the fixtures, testing as you go.
I don't spend a lot of time trouble shooting a circuit. I prefer to just run a new wire and I know the problem is gone and will not return.
Good luck
Gary
testing resistance
Gary et al,
When testing for resistance with our standard 16 gauge primary wire, will the ohmmeter read zero or show some resistance in a non-open circuit? This is an underutilized resource on my vessel. My VHF quit last trip and it took me a little while to track down the corroded and broken wire at a butt connector.
Chase
When testing for resistance with our standard 16 gauge primary wire, will the ohmmeter read zero or show some resistance in a non-open circuit? This is an underutilized resource on my vessel. My VHF quit last trip and it took me a little while to track down the corroded and broken wire at a butt connector.
Chase
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barfwinkle
- Posts: 2169
- Joined: Feb 6th, '05, 10:34
- Location: S/V Rhapsody CD25D
Poltergeist Exercised
Well it took a while but I got rid of that little bugger. The problem was the main ground wire coming off of the volt meter in the distribution panel. It had Corroded and broken into where it was attached to the engine block! GREAT NEWS!! 
Seadawg had it right
Fair Winds and happy fire crackers!
<a href="http://www.boatsafe.com/nauticalknowhow ... .htm">Boat Electricity 101</a>
Seadawg had it right Chase I agree with you. I had to do an internet search this morning prior to going to the boat because I dont use the multimeter often enough to remember how! So here is a link that I found and it helped me out. Hopefully it will prove useful for others.When testing for resistance with our standard 16 gauge primary wire, will the ohmmeter read zero or show some resistance in a non-open circuit? This is an underutilized resource on my vessel.
Fair Winds and happy fire crackers!
<a href="http://www.boatsafe.com/nauticalknowhow ... .htm">Boat Electricity 101</a>
Bill Member #250.
Testing resistance
Chase,
I like to isolate the circuit so I'm sure I'm not reading something that has nothing to do with my issue.
A non open circuit?
If we're working on cabin lights and that type of thing, then your meter will read the resistance of everything on the circuit. The wire, the light bulb filament, every connection, everything.
If I isolate that same circuit, and remove the first fixture, I should read infinity, or open. If I read some resistance then there is either another fixture on the circuit or I've got a bad wire run.
Gary
I like to isolate the circuit so I'm sure I'm not reading something that has nothing to do with my issue.
A non open circuit?
If we're working on cabin lights and that type of thing, then your meter will read the resistance of everything on the circuit. The wire, the light bulb filament, every connection, everything.
If I isolate that same circuit, and remove the first fixture, I should read infinity, or open. If I read some resistance then there is either another fixture on the circuit or I've got a bad wire run.
Gary
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barfwinkle
- Posts: 2169
- Joined: Feb 6th, '05, 10:34
- Location: S/V Rhapsody CD25D
Inifinity or Open or short
Hi Gary
There in lies one of my problems! I never can remember the correct jargon for this job.
So if I am testing a 12 inch lenght of wire and I palce the probes on each end, what kind of reading should I get assuming that the wire is "good" wire. Or perhaps this on is better a light bulb that is functioning properly. Open? Infinity? short (i would not think so if they are "good".
I just dont do this often enough to remember! Some say it has to do with old age! I say it has to do with too many good times!
Thanks and fair winds
There in lies one of my problems! I never can remember the correct jargon for this job.
So if I am testing a 12 inch lenght of wire and I palce the probes on each end, what kind of reading should I get assuming that the wire is "good" wire. Or perhaps this on is better a light bulb that is functioning properly. Open? Infinity? short (i would not think so if they are "good".
I just dont do this often enough to remember! Some say it has to do with old age! I say it has to do with too many good times!
Thanks and fair winds
Bill Member #250.
Infinity or short
Barfwinkle,
It's easy to remember.
With the selector set for resistance touch the two probes together and your meter will read a "dead short." You could also call this a closed circuit. The display will read 1 ohm or 1.1 ohm or something very low. It's actually reading the resistance in the wire leads.
So if you put one probe on one end of a 12 inch piece of wire and the other on the other end you will again read a short or closed circuit. Something like 1.2 ohm. Unless of course the wire is broken, then you will read infinity. Infinity is open.
If you read the two poles of a good light bulb you will read a short, or very low ohms because the voltage from your meter can run through the filament to your other probe.
If the filament is broken, a bad bulb, you will read an open or infinity.
A short is like touching the two probes of your meter together.
An open is like taking the two probes apart.
Think of it as open or closed if it is easier.
Infinity is open. When working on more complicated electronics the words infinity and open may be more distinct but they really mean the same thing. When you look at your meter display when the probes are not touching, that is the display for infinity. It's also the display for open.
If you haven't used your meter in a while, turn it on, select resistance then observe the display as you touch and separate the probes. now your ready to go.
The investigator in you has to find out why a circuit that should have low resistance now reads high resistance. It could be a damaged wire that has corroded or it could be a splice that just needs cleaned up.
I trouble shoot all the time on my job and use a simple process of elimination. I check the most obvious things first and then just start eliminating things until I find the culprit.
Talk to you later.
Gary
It's easy to remember.
With the selector set for resistance touch the two probes together and your meter will read a "dead short." You could also call this a closed circuit. The display will read 1 ohm or 1.1 ohm or something very low. It's actually reading the resistance in the wire leads.
So if you put one probe on one end of a 12 inch piece of wire and the other on the other end you will again read a short or closed circuit. Something like 1.2 ohm. Unless of course the wire is broken, then you will read infinity. Infinity is open.
If you read the two poles of a good light bulb you will read a short, or very low ohms because the voltage from your meter can run through the filament to your other probe.
If the filament is broken, a bad bulb, you will read an open or infinity.
A short is like touching the two probes of your meter together.
An open is like taking the two probes apart.
Think of it as open or closed if it is easier.
Infinity is open. When working on more complicated electronics the words infinity and open may be more distinct but they really mean the same thing. When you look at your meter display when the probes are not touching, that is the display for infinity. It's also the display for open.
If you haven't used your meter in a while, turn it on, select resistance then observe the display as you touch and separate the probes. now your ready to go.
The investigator in you has to find out why a circuit that should have low resistance now reads high resistance. It could be a damaged wire that has corroded or it could be a splice that just needs cleaned up.
I trouble shoot all the time on my job and use a simple process of elimination. I check the most obvious things first and then just start eliminating things until I find the culprit.
Talk to you later.
Gary
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Oswego John
- Posts: 3535
- Joined: Feb 5th, '05, 20:42
- Location: '66 Typhoon "Grace", Hull # 42, Schooner "Ontario", CD 85D Hull #1
Poltergeist cont'd
Gary, That was a very good explanation that you gave to Bill and other readers. With your permission, I would like to expand on the subject a bit, not for the type of troubleshooting that Bill and others are doing. Moreso to jog the memories of the many Short Wave and ham afficionados and circuit designers on the board.
I'm trying to say several things at one time, so I'll break it up into segments. For fine detail work with resistance, many aren't aware that the meter has to furnish it's own power to read continuity on dead circuits. The resistance settings incorporate their own battery(ies) Weak batteries will render false readings.
To zero in on accurate ohmage readings, the tech should utilize the correct resistance meter setting, coarse, mid range and fine. Furthermore, the meter leads should be shorted and the zero adjust knob should set the needle, or wand, to zero on the dial face. Some electronic numeric meters are self regulating, eliminating much of this procedure.
When I broke in to the business, our labs and shops relied on VTVMs. That's a fancy term for vacuum tube volt meters. Yes, powered by vacuum tubes. Back in the early and mid 1950s, some brash upstarts somewhere down in Texas started a business called, I think, Texas Instruments. The young whippersnappers unfairly used gizmos called transistors in their equipment and the electronic tube industry was never the same henceforth.
Looking back to then, compared to the test equipment being used today, it is truly amazing that we ever got a man onto the moon by use of that crude equipment. Oscilloscopes of the day were well beyond our financial reach. Many of us built our own test equipment with Heath Kits. Benton Harbor, Michigan. Anyone remember them? If you do, you're dating yourself.
In closing, I'll just mention for smiles but wont go into detail how the TV Tech checked out your ailing 8" screen TV set. You probably wouldn't believe me if I told you.
Well Gary, good job. See what you started?
Just sitting here with a smile, reminiscing a bit with fond memories of earlier days.
O J
I'm trying to say several things at one time, so I'll break it up into segments. For fine detail work with resistance, many aren't aware that the meter has to furnish it's own power to read continuity on dead circuits. The resistance settings incorporate their own battery(ies) Weak batteries will render false readings.
To zero in on accurate ohmage readings, the tech should utilize the correct resistance meter setting, coarse, mid range and fine. Furthermore, the meter leads should be shorted and the zero adjust knob should set the needle, or wand, to zero on the dial face. Some electronic numeric meters are self regulating, eliminating much of this procedure.
When I broke in to the business, our labs and shops relied on VTVMs. That's a fancy term for vacuum tube volt meters. Yes, powered by vacuum tubes. Back in the early and mid 1950s, some brash upstarts somewhere down in Texas started a business called, I think, Texas Instruments. The young whippersnappers unfairly used gizmos called transistors in their equipment and the electronic tube industry was never the same henceforth.
Looking back to then, compared to the test equipment being used today, it is truly amazing that we ever got a man onto the moon by use of that crude equipment. Oscilloscopes of the day were well beyond our financial reach. Many of us built our own test equipment with Heath Kits. Benton Harbor, Michigan. Anyone remember them? If you do, you're dating yourself.
In closing, I'll just mention for smiles but wont go into detail how the TV Tech checked out your ailing 8" screen TV set. You probably wouldn't believe me if I told you.
Well Gary, good job. See what you started?
Just sitting here with a smile, reminiscing a bit with fond memories of earlier days.
O J