testing HU preouts

[2002XLT 5,000+ posts]

Ok, im going to be testing some units i have for sale to make sure they work, i know the trick about hooking it straight to your battery, and ill connect it to a speaker to make sure the internal amp works, but how should i go about checking the preouts? I have a dmm, just not sure what settings to set it on, and what i should see on the display. Thanks.

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[dman4486 5,000+ posts]

set on volts ac (vac) and look for whatever voltage your hu is supposed to put out...red(+) to the center pin, and black(-) to the shielding

 

[2002XLT 5,000+ posts]

what do you mean by center pin and shielding, dont i just hook the red to red, and black to black?

 

[dman4486 5,000+ posts]

what do you mean by center pin and shielding, dont i just hook the red to red, and black to black?

testing rca's? there is a center pin that carries the signal, and the shielding is ground...you are looking for voltage on the center pin

 

[Tacosys 10+ year member]

The center pin is the pin in the middle, put the positive on that. The shield is the metal that goes around the RCA, put the negative on that.

 

[2002XLT 5,000+ posts]

so i do this to each individual RCA? Because there is a red and black, i figured the red would be positive and the black negative.

 

[dman4486 5,000+ posts]

so i do this to each individual RCA? Because there is a red and black, i figured the red would be positive and the black negative.

yes do it to both...red is right black is left usually

 

[2002XLT 5,000+ posts]

Oh ok, i guess i didnt think too far into it. lol. so they should both read the same level right? And just check each individual RCA with the red inside and the black to the shield, and will give me some sort of reading. Thanks.

 

[jco1385 5,000+ posts]

joo is gonna test that 4700?? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[grampi 10+ year member]

Oh ok, i guess i didnt think too far into it. lol. so they should both read the same level right? And just check each individual RCA with the red inside and the black to the shield, and will give me some sort of reading. Thanks.

Don't forget that you need to have the HU playing some source (like a CD or the radio and have the volume turned up high enough to see a voltage). For example, if your HU has 4 volt preouts, you should be able to play a CD and with the volume turned all the way up, you should see 4 volts, or very close to 4 volts (like 3.9X).

 

[2002XLT 5,000+ posts]

joo is gonna test that 4700?? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

i dont know, i thought about it, but i actually left it at home when i went for lunch. if it doesnt work, you wont want it anymore, and if it does work ill want more for it. lol. not sure what to do about that.

Don't forget that you need to have to HU playing some source (like a CD or the radio and have the volume turned up high enough to see a voltage). For example, if your HU has 4 volt preouts, you should be able to play a CD and with the volume turned all the way up, you should see 4 volts, or very close to 4 volts (like 3.9X).

good point, thanks.

 

[jco1385 5,000+ posts]

nah i was joking man. too late now cuz my money is en route. but if you do decide to test it lmk the results. but if its good dont do me dirty

 

[2002XLT 5,000+ posts]

well you may have gotten lucky, all the others get power and work.