Depth Sounder Questions

[giantgourami]

I have just aquired a boat with an Eagle Strata 128 Depth sounder . The trouble is that both the positive & negatives were wired to positives only. This has caused the screen to not work anymore..I need to know whether anyone knows of what it is worth to fix this ...I also need to know what people reccommend is the best depth sounder for 400 - 500 dollars.

Cheers in advance
adam

[Heath]

If both the + & - were wired to the + only it wouldn't have harmed the unit at all, as there would have been no cct.

First make sure you have power at the plug of the sounder & ensure it is correct polarity. If you sounder then doesn't work, well....... then its stuffed.

I don't know how good a sounder the Eagle Strat 128 is, but if it's any less than say $400.00 then it probly wouldn't be worth fixing.

[clutter]

I have a Lowrance X71 and find it very good. It was about $550. The X51 is a smaller screen but has a large pixel count (can't remember the number) and as a result has a very clear picture. They are a bit cheaper and are a very good unit.
Cheers, Clutter.

[Fitzy]

Here's some prices on various sounders under $500.

Lowrance X51 $359
Navman 4100 - $329
Navman 4150- $435
Navman 4200 - $499
Humminbird 150 SX - $345
Humminbird 250 DX- $439
Garmin FF100 - $379
Garmin FF100 Blue - $499

Cheers,

Fitzy..

[squire]

Adam you may find that you have either blown a fuse internally if it has one if not you will find it will have cooked one of the resistors on the circuit board. Sorry heath if both were connected to the positive the a circuit would have been complete hence a blown circuitry component. Adam message me and I will quite happily have a look at it for you regards Squire.

[klyons]

Hey Squire
Has someone rewriten the laws of physics while I wasn't looking. ???
Both leads to the pos DOES NOT create a circuit. To create a circuit there must be a return path for the current. With both leads on the same terminal, no current flow is possible.
The theory of electical flow is similar to any other flow. If you connect both ends of your garden hose to the same tap and then turn it on, do you think water will flow through the hose?? ;D ;D



Kev

[Fitzy]

Tend to agree with Klyons & Heath. I can't see how both wires to one side of a battery could hurt any electrics. Can't see how a circuit was completed.

Or am I a total ijit? (Don't answer that) ::) :P

Fitzy..

[squire]

Sorry guys I shall rephrase that. What I mean is that a positive flow through a circuitry board where there is a resistor and a voltage regulator will burn out or pop a resistor. I'm not talking about a completed curcuit on the boats system Ie +ve and _ve. Sorry heath I misread the statement. however sometimes when you have 2 wires connected to a +ve you can actually become the -ve especially in an aluminium boat.

[squire]

Kylons your tap statement amazes me.If you joined the two taps together water wouldn't flow. However eventually the hose would burst due to the pressure. Hence a resistor joined to the same tap will do the same. thats the world of electronics. thanks for the thought I shall remember it when I connect the positive and Earth together next time I wire a house and see if someone gets electrocuted. you dont have to have an Earth or negative in a curcuit either it can be introduced later ie if positive curcuit exists you can become the earth by touching it. oh and the laws of physics. For every action there is an equal and opposite reaction. regards squire

[giantgourami]

The reasons that the unit isnt working may or may not be from this ..It was just a guess .It is a new boat that we just purchased and that was how it seemed at the time.

Squire it would be great for you to look at it but I think that I will get a new Navman 4200 instead.The Navman warranty seems fantastic and the Fuel transducer option will be needed by us as we have no fuel guage on the underfloor tank.

I played around with the eagle last night out in the bay and it works now but only half heartedly .It comes on with a blurry screen and then after about 15seconds it goes out. Does seem like something dodgy but Squire if you are still willing to look at it, it would be great for the tinny that my mate is buying if it can work again.

Cheers Adam

[klyons]

Squire

Are you sugesting that the pressure in the hose will continue to rise till the hose bursts. ??? ::) From where will this pressure increase come ???.If the hose was going to burst from the pressure it would do so as soon as the tap was turned on.
My reference to flow re water and electricity, both will take the path of least resistance. If there is no path there is no flow

Kev

[squire]

kev we could go on about this for ever. However before I delve into this conversation any more, question. Are you aware of what a resistor is and what its function is? Do you Know what happens if you decrease current in relation to voltage? as for the hose leave it on for a week and see what happens and your not allowed to use locktite on you fittings either. anyway you know what you know and I know what I know so well leave it at that.

[Fitzy]

OK folks, think we've covered the bases on electrons etc.
Lets leave the tangent topic at that & get back to the original one hey? ;)

Cheers,

Fitzy..

[elmo]

Back to the matter at hand.

There is no way on God's earth that having both wires conected to the positive and not having the chasis grounded (assuming the negative is also grounded) did any damage what so ever to the appliance. Ohm's law forbids it. For current to flow there must be a pressure (voltage) and the resistance to this pressure is called funnily enough resistance(or reluctance, reactance, impedance). If there is no potential difference across the resistance. i.e. return path for the voltage, be it a lesser potential say 12 volts to 6 or to a -ve or ground, there will be no flow of electrons.

[team_mongo]

Adam,

For a electricty to flow there must be a voltage across the circuit (this is described using ohms law V=IR). If you connect the 2 leads of any circuit to the same potential beit 3V, 12V, or 20000V there is no potential difference and thus no current. The only exception to this is if the device is EXTERNALLY grounded. This is not the case in all sounders or portable devices that I know of but is common in AC applications to prevent leakage to metal surfaces and thus making cases live (The reason for this is that AC has much higher penertration of human tissue than DC, and thus can electrocute at very low amperage when compared with DC).

The anology with water is a good one for DC, but there is no flow and no differential pressure, the wire will not 'burst' - a simple analogy would be to get a piece of wire, nick the insulator ar two points and solder these to nicks together. Nothing would happen to the wire, and if you put an inductive ammeter on it, it would read zero (because there is no voltage drop over that loop). Believe me Adam nothing has happened to your sounder, just hook up right. If it dont work, its not because of the way it was wired.

Cheers
George

[squire]

no can't help myself fitzy sorry.IF ALL THE ABOVE WERE TRUE Can someone please tell me WHY DO WE HAVE FUSES IN CARS ON THE POSITVE WIRES? THEY WOULD SERVE NO PURPOSE!!!!!!!!!

Im not disagreeing with you guys. however the hose analogy. It would eventually burst due to the fact that the Water main has a greater pressure in it and if nothing else was connected to it, it would withstand the outside pressure for a while that is it. ie different amperage wire 10 amp wire 5 amp fuse. 5 aMp fuse will blow. Resistors in circuitry are exactly the same. However we all agree that there has to be and outside influence to make this happen and sometimes this can occur.Its like saying my boat #motor started yesterday but won't start today. It is not about who is right or wrong. We all know the laws of Physics so with all of us knowlegeable people we should be able to fix adams sounder don't you think? Lets leave it alone.

[elmo]

Most cars have their negative terminal earthed to the chassis, some European cars don't and then it doesn't matter whether the fuse is close to the positive or negative. (but be vey careful with radios cd players etc as some have positve bodies) However, it is convention and safe practice to locate the fuse as close as possible to the source.

Fuses in cars with common chassis and negative terminals are on the positive wires because they need to be as close as possible to the source of energy in case of a fault.
Just say you accidently or inadvertently melted or rubbed the insulation off the conductor. It is quite feasible that the fuse didn't blow because there was no circuit (return path). Now, if this bare section of conductor is moved and touches the chassis, it is in effect a dead short across the supply with absolutely no protection.

This can lead to fires or even explosions.

[elmo]

quote: It would eventually burst due to the fact that the Water main has a greater pressure in it and if nothing else was connected to it, it would withstand the outside pressure for a while that is it.

Wrong, the water main has more than likely a greater flow potential but exactly the same pressure.

[elmo]

The pressure of your home water system is determined by the height (head) of water. That's why towers and reservoirs reach up to the sky.

For example.

I'll assume straight sided towers for ease of area calculations.

Pressure is defined as force per unit area. (pounds per square inch)

Tower One has dimensions of 1 foot wide by 1 foot deep by 10 feet tall.
Volume = width x depth x height = 10 cubic feet
Water weighs approx. 62 pounds per cubic feet so the total weight is equal to 620 pounds (62 x 10)
Area = width x depth or 1 square foot or 144 square inches
Therefore pressure = 620 pounds divided by 144 square inches = 4.3 pounds per square inch.


Tower Two has dimensions of 10 feet wide by 1 foot deep by 1 foot tall.
Volume = width x depth x height = 10 cubic feet
Water weighs approx. 62 pounds per cubic feet so the total weight is equal to 620 pounds (62 x 10)
Area = width x depth or 10 square feet or 1440 square inches
Therefore pressure = 620 pounds divided by 1440 square inches = 0.43 pounds per square inch.

Only the height (head) of water effects the pressure.

[squire]

Yep thats great Elmo got absolutely no idea what you're talking about but thanks for your thesis. Gravity is an amazing thing isn't it?
does the same apply for a dam?

[Big_Muddie]

I can't help but make a comment on this thread.

Lot's of lively debate about many things - maybe not specifically addressing the original post but informative nonetheless.

From many of the posters I have learned some things that I was previously not greatly interested in - but the debate here sparked (sorry - couldn't help myself there) my interest and resulted in my store of knowledge being increased.

Thanks particularly to Elmo for the explanation of water pressure and basic car electronics.

[giantgourami]

How about I add this in..... and you can all come up with your theories..

The actives where not from the same battery.. one was from the main and the other was from the spare .. would this make a difference?


anyway what you gots to say about navmans?


adam

[predator]

and a word from Professor Julius Sumner Miller.






























asks. "Why Is It So?".


;)

;D ;D ;D ;D

[Heath]

Adam you may find that you have either blown a fuse internally if it has one if not you will find it will have cooked one of the resistors on the circuit board. Sorry heath if both were connected to the positive the a circuit would have been complete hence a blown circuitry component. Adam message me and I will quite happily have a look at it for you regards Squire.

How??? Conventional flow of electrons IE from POS to NEG. If there was no neg polarity how could there be current flow?

I'll use a simple example a 12v light globe with both ends connected up to only the Positive. Will it light up?...no, can you measure voltage across both leads when connected up to 1 pol only???

Not slinging mud Squire, just interested in how it could have caused damage to circuitry if it was connected to 1 pol only. :)

[Heath]

How about I add this in..... and you can all come up with your theories..

The actives where not from the same battery.. one was from the main and the other was from the spare .. would this make a difference?


anyway what you gots to say about navmans?


adam
Ahhhh now we get to the root of the cause.
YES it makes a BLOODY big difference ;) ;D

You now have a cct. Both batteries will have #their earths connected together. Especially with 2 batteries, you have the problem of each battery not being the exactly the same voltage. Now lets say you have 1 battery & is fully charged at 12v & the other battery which has been used is say sitting at 10v, if you measure accross them you will measure 11v, now what happens when you connect up 2 batteries in this situation is that the flat battery will draw current from the good battery, eventually equalising at the sum of the 2 original voltages, this is called equalising.

What you have done is made a connection that has attempted to achieve this through your little sounder & as a result its gone KAPUT!

Ahhhh, dear o' dear..... good clean debate though fellas #8)

[squire]

Heath if you read post 7 I corrected myself. So here it is again.
Sorry guys I shall rephrase that. What I mean is that a positive flow through a circuitry board where there is a resistor and a voltage regulator will burn out or pop a resistor. I'm not talking about a completed curcuit on the boats system Ie +ve and _ve. Sorry heath I misread the statement. however sometimes when you have 2 wires connected to a +ve you can actually become the -ve especially in an aluminium boat.
Regards Squire.

[squire]

There we have it the outside influence. Can we all agree on that?