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Old 20th March 2009, 08:48 PM   #11
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Measuring the Ohms/resistance is where the needle deflects fully to the left, i.e. less than zero. It pegs in the full negative position, all the way to the stop....off the chart.

And the meter does require I change a setting to measure amps. It is the turn of a knob.

Thanks again.
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Old 20th March 2009, 08:55 PM   #12
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Does you meter have a 'zero' adjustment to get the meter to read 0 ohms with the probes touching?
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Old 20th March 2009, 10:53 PM   #13
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Perry:
Quote:
Does you meter have a 'zero' adjustment
You gotta love analog equipment!

BTW caraudio, how old is the battery?
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Old 20th March 2009, 11:05 PM   #14
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Yes, there is a zero adjustment, but I can only adjust it a very small amount. There is no way to get the needle over to the right enough for the needle to not be pegged to the left when measuring the ohm/resistance. It is a pretty violent leftward motion when I place the probes on the B+ and ground on the amp. It pegs pretty hard.

tsmith. Hey, thanks for the reply. The battery is 3 years old, which is about time to start thinking about another battery. However, my wife's battery had an issue where we got AAA to come out and test hers just a week ago. I went ahead and got them to test mine too because I had that drain issue with my other amp many months back. The diagnosis was great. All systems normal. They even gave me a print out of the report.

I don't really know what to do about measuring the Ohm/resistance. Is this an erratic behavior for an amp to be doing?
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Old 20th March 2009, 11:18 PM   #15
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I was trying to determine if there was leakage across the B+ and ground terminals but if you can't zero the meter with the probes touching together, I don't think it's going to be possible with that meter. Changing the battery in the meter may make it possible to zero the meter.
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Old 20th March 2009, 11:32 PM   #16
ppia600 is offline ppia600  United States
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The meter is pegging out on resistance because of the capacitors in input side of the power supply. You have to wait and let it unpeg, eventually the resistance will stay constant. That is why Perry was wanting you to take a short piece of wire and jump the two amp power terminals to dissipate any residual voltage stored in the caps. It may still peg the meter depending on its sensitivity, but it will eventually level out. You may have to wait 15 or 20 seconds.
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Old 20th March 2009, 11:46 PM   #17
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Ok, you guys are pretty good. I did as described. I jumped the two power terminals with a short piece of wire. I then was patient with the Ohm/resistance reading. It actually took 2 minutes for it to unpeg, and when it finally did 5 minutes later it just reads 0. Is this what it's supposed to do? All this is over my knowledge of electricity.

I then, to try to understand a bit what's going on, measured the amp draw and it was really high. I started all over again with the short piece of wire, and then measured the Ohm/resistance and it again took 2 minutes to get the needle off the peg and shortly after it read 0 and nothing more.

I'm not really sure what all of this is doing, like I said I'm not knowledgeable of this area. But just let me know when to do what, and if this will allow my amp not to drain my battery. Thanks again, guys.
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Old 20th March 2009, 11:48 PM   #18
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What make/model meter do you have?
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Old 20th March 2009, 11:52 PM   #19
ppia600 is offline ppia600  United States
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Also, how long are you waiting while reading amp draw? Does it keep drawing 2 amps for longer than say ten seconds?
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Old 21st March 2009, 02:23 PM   #20
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The meter is a Sperry SP-5A, a $10 meter from Lowe's or HD. Every other thing I am measuring is spot on, so I think it is reliable despite its cheapness.

ppia600, I hadn't measured that so I just went and did it. I waited about 2 minutes and it was still reading 2 amps.

So I've also done other testing. I brought the amp to the front of the car under the hood and used different cables. I hooked the ground to a different ground point, and used a short piece of cable for the B+. The exact thing was happening, 2 amp draw. So this confirms that it is not any wiring issue with the the existing wires in my car.

I then thought it might be a battery issue, so I went to my wife's car and did the exact thing as described above with the new wires -- ground to new ground and new short cable to B+. Still same thing, 2 amp draw. So this isolates a battery issue with my car battery.

So we're back to the amp. Is this brand new amp a defective amp, and just by coincidence it does the EXACT same thing as my old amp??!!?
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