PDA

View Full Version : Component troubles



swiftone
01-26-2006, 06:05 PM
So I recently installed components in my car, and I have noticed that one side is audibly louder than the other side. When I switch the RCA cables going to the amp, the quieter side switches.

I posted this problem in the past and I was told 3 possibilities:

1. The RCA cables are pinched somehwere or defective
2. Speakers out of phase
3. Defective/broken head unit.

Today I tried new RCA cables and the problem persisted. Before I invest in a new head unit, I would like to once again appeal to some troubleshooting suggestions. I am not quite sure how to test for speakers being out of phase, other than opening up my door panel and checking the pos/neg from the tweet to the crossover, mid to the crossover, crossover to amp on both sides (which is needless to say, a tedious task). Any opinions on this problem or what my next step should be would be grealty apprecated, thanks!

squeak9798
01-26-2006, 06:47 PM
Grab a DMM, play a test tone (volume level doesn't matter) and measure the voltage on each RCA. Unplug the RCA's from the amp, put the red DMM lead on the inner prong of the RCA connector and the black DMM lead on the outter metal shield. They should measure the same voltage. If they don't, then you know the problem is either the HU's preamp outputs or the RCA's. If they do, then you know the problem comes after the RCA's.

If they don't measure the same, pull out the HU and directly measure the HU's RCA outputs. If they measure differently, then you know the problem is the HU itself. If they don't measure different, then you know the problem is the RCA's.

swiftone
01-26-2006, 07:06 PM
Grab a DMM, play a test tone (volume level doesn't matter) and measure the voltage on each RCA. Unplug the RCA's from the amp, put the red DMM lead on the inner prong of the RCA connector and the black DMM lead on the outter metal shield. They should measure the same voltage. If they don't, then you know the problem is either the HU's preamp outputs or the RCA's. If they do, then you know the problem comes after the RCA's.

If they don't measure the same, pull out the HU and directly measure the HU's RCA outputs. If they measure differently, then you know the problem is the HU itself. If they don't measure different, then you know the problem is the RCA's.

Just wanted to make sure I am doing this right so I dont break anything. Do you mean connect the red DMM to the metal of the unplugged RCA cable itself? Also I am not sure what you mean by connecting the black DMM to the outer metal shield.

Ive never used one of these before and I dont wanna accidently short something by connecting the wrong thing to something else.

squeak9798
01-26-2006, 09:07 PM
Just wanted to make sure I am doing this right so I dont break anything. Do you mean connect the red DMM to the metal of the unplugged RCA cable itself? Also I am not sure what you mean by connecting the black DMM to the outer metal shield.

Ive never used one of these before and I dont wanna accidently short something by connecting the wrong thing to something else.

http://gallery.caraudio.com/vg/1/4/7/3/6/RCA.gif

The colors indicate what color lead from the DMM gets connected to what part of the RCA connector.

swiftone
01-28-2006, 03:03 PM
Ok so I have never used one of these thigns before so i wasnt sure what all the settings meant. Anyhow, the results were as follows:

Using a 1kHz test tone:

On the setting V with a straight line and dotted lines, on setting labeled 2

Left: .164
Right: -.027

On the setting V with a ~ under it at setting 2

Left: .514
Right: .233

Im no scientist but I am quite sure that means the right preout is not working on the heat unit...

squeak9798
01-28-2006, 03:10 PM
Yeah...it appears that the Right output isn't working correctly.

Double check all of the settings internally in the HU to be sure there are no settings that could be causing that (such as fader, balance, other forms of attenuation, etc). If all of that is okay, then it sounds like you just have a malfunctioning headunit.