Adjusting Voltage Meter
- Thread starter rpwillia
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I'm not familiar with the type of voltmeter Catalina uses so it may not be possible to adjust it without a variable resistor in the circuit. It sounds like the meter's internal resistance has changed creating a higher apparent reading so replacing it should cure the problem. If you cannot do that but have some basic understanding of Ohm's Law, you can add a variable resistor of sufficient current rating to compensate.
Did not see an adjustment screw in PaulJ's Picture
Of course I did not see any labels either. I actually do understand Ohm's law E=I*R or a variation on that them. So I know E should be 14.5 volts, but finding I or R may take a little more research. Perhaps I can find the make and model in PaulJ's picture and RTFM.
Measure the current draw in series while operational, then measure the resistance when off. Then use Ohms law to calculate what the E should be.
Generally for analogue meters there is a zeroing screw for the needle adjustment, not sure on our unit, but zero it first before you do the actual E reading. Then when you do your calculated E there will not be an additional offset applied to the delta. To correct for high reading add R to the input to ground. If it is reading too low, than the coil is not drawing enough current and probable needs to be replaced. There also may be some an obstruction due to corrosion preventing the needle to swing freely.
In PaulJ's photo of the guts , there looks like some kind of red adjustment screw in the upper right corner of the guage ...............??
Will post an update
I will make it down to the boat this weekend to check, but I think the red is some type of cover. But my memory is a bit hszy as it was about 5 months ago I had the cover off and (are you all ready for this? Really ready?) PaulJ did not label that so I am not sure!
I will make it down to the boat this weekend to check, but I think the red is some type of cover. But my memory is a bit hszy as it was about 5 months ago I had the cover off and (are you all ready for this? Really ready?) PaulJ did not label that so I am not sure!
rpwillia
I don't trouble shoot electronics any more but it starts with..... signal in then signal out
E=IR is for designing components.
If you have an existing component, you have to check how it works over the existing scale that is shown on the instrurment...so you need a signal generator......10 volts in then 11,12,13 etc and see where the needle lands on the scale and also see the true range of the meter........My brain is tired already but I think you will catch on.
paulj :troll:
I don't trouble shoot electronics any more but it starts with..... signal in then signal out
E=IR is for designing components.
If you have an existing component, you have to check how it works over the existing scale that is shown on the instrurment...so you need a signal generator......10 volts in then 11,12,13 etc and see where the needle lands on the scale and also see the true range of the meter........My brain is tired already but I think you will catch on.
paulj :troll:
rpwillia
I had to look this one up on the internet.
"Read The F***ing Manual" or RTFM, is an expression that can not be spoken
out loud, but cannot be repeated often enough
paulj :troll:
I had to look this one up on the internet.
"Read The F***ing Manual" or RTFM, is an expression that can not be spoken
out loud, but cannot be repeated often enough
paulj :troll:
I am working hard to fix my old habits
Sometimes it is better I use acronyms. But WTF, it's all good!
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