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I checked today the green and the blue wire coming from the cpu.
According to what Mirage told me , the blue is ground triggered during an alert ,
and the green becomes positive 5 volts.
But i found that both , green\blue , are grounded all the time : when the system is close as well powered .
Is there something or a setting that is incorrect ?
Thanks.
How are you measuring it? If you measure it relative to ground, it'll always be zero volts. You should connect the + lead of your voltmeter to a 12V source and the - lead to the mute wire. Then the meter should read 12V when the ground (mute) is active and 0V if it isn't.
It should active when alerting (jamming).
I made a continuity test : negative lead of the voltmeter to chassis and the positive lead to the blue\green : circuit is closed.Quote:
Originally Posted by radargeek
When i was doing the same test with the Li , the circuit was open under no alert and closed under alert with the Osprey.
I have no way to trigger an alert , no tester no gun :chargrined:
I will test your way '' + lead of your voltmeter to a 12V source and the - lead to the mute wire.
Then the meter should read 12V when the ground (mute) is active and 0V if it isn't.''
I just tested as you suggest.
Took a wire directly from the battery +
Blue wire :
Alp Off : zero volt.
Alp On : blue mode : 5.46 volts (under no alert)
That's odd. I'll take a look again in the morning and make a video. Maybe you can spot a difference in what you are doing vs what I am.
Very nice of you.Quote:
Originally Posted by mirage
Tia :popcorn:
It's probably a floating pin (not connected to anything) during no alert, and it gets shorted to ground during the alert.
Now if you put a voltmeter across it, remember what a voltmeter does. It is supposed to measure the voltage across two points. How does it do this, without changing the voltage? Well technically, this is impossible. What it does is it acts as a VERY high resistance resistor, and measures the (very small) current to determine the voltage. For most circuits, the resistance of the voltmeter will be orders of magnitude larger than any other resistances in the circuit, meaning that the voltage will NOT change much due to the presence of the very high resistance resistor.
But what if there is a pin that's floating? Well, since it's not connected to anything else, when you put one end of the voltmeter on that pin and the other on ground, the voltage on that pin will very quickly equalize (only a small current needs to flow through the voltmeter to discharge whatever little capacitance there is in that pin) to ground.
So what you want to do is put a voltage source on that pin, and see that the voltage is approximately equal to that of the voltage source. Put a small resistor between the voltage source and the pin, then trigger an alert. If the pin's voltage gets pulled down almost to ground, then you know what's going on. Another way to measure this is to put the meter into ohmmeter mode (measure resistance). Just be careful not to blow any fuses. If I am correct, we would see nearly infinite resistance when not alerting, and nearly zero resistance when an alert is triggered.