My friend is having a head unit problem.

[Brian235]

hello everyone the other day my friend was telling me about a problem he had. He said he hit a bump or something of the sort and his stereo stopped working (aftermarket head unit amps subs, and speakers.) I told him to head over my house. Before he came over he told me that he inspected his system and there was a broken male end of an rca going to his amp, he repaired it. When he got over I inspected that his head unit turned on, but only put out faint sound at max volume It wasn't any settings with the head unit, gains on the amps ect. the head unit simply was not putting out any sound to either of the rca outputs. Myself im guessing the damage that was done to the rca's possible short circuited the head unit? He didn't have much time when he came over this time so I couldn't pull out the head unit and inspect the fuse or the rca connections in the back any recommendations for when he comes over next?

I tested both of his amps for damage and both were working just fine.

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[dev199505]

Are all speakers on amps or just the sub? I'd put a DMM to the amp end of the RCA's to see if the head unit is putting out any voltage. If no voltage at that end pull the HU and check the HU its self

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[Brian235]

Are all speakers on amps or just the sub? I'd put a DMM to the amp end of the RCA's to see if the head unit is putting out any voltage. If no voltage at that end pull the HU and check the HU its self
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its both the RCA's that are coming from the head unit, Thats what I did neither rca are putting out any voltage, the voltage these RCA's should be putting out is somewhere around 4 volts but i got around under .02 at max volume I was wondering how about I should go about checking the HU itself for damage

 

[wew lad 5,000+ posts]

if the headunit turns on and has no pre out voltage, and the amps work just fine with a secondary signal source, diff headunit, or aux to RCA into the amp, then its a bad headunit.

i dont know anyone who repairs headunits... he just needs to hope its a cheap hu and to learn his lesson next time.

i would verify theres no settings in the headunit menu muting output or reducing it

 

[Brian235]

if the headunit turns on and has no pre out voltage, and the amps work just fine with a secondary signal source, diff headunit, or aux to RCA into the amp, then its a bad headunit.
i dont know anyone who repairs headunits... he just needs to hope its a cheap hu and to learn his lesson next time.

i would verify theres no settings in the headunit menu muting output or reducing it

I already tested both amps with an aux to rca and all of the channels/sub puts out music perfectly fine, was around 200$ hu he is fine replacing it which will probably be the case. When he comes over next I will recheck the settings of the hu again I already did but maybe I missed a setting and make sure all of the connections to back of the hu are secure ect.

I was just wondering if anyone had any incite as to what may have caused the damage / ways to check the hu for what damage was done, the male rca's into the amp were not damaged untill when he recently check after his HU stopped putting out signal (according to him).

 

[wew lad 5,000+ posts]

its hard to say, sometimes shorting out a rca will kill the outputs, sometimes nothing happens. some headunits will run into problems unplugging rcas with them still on due to the voltage spikes.

some headunits fail over time due to vibration and dust, some are just cheap quality.

i would put the dmm on the power and ground into the headunit just to verify its a good stable 12v source, as well as the remote 12v in from the ignition. likely not a problem but id check

i honestly cant think of anything else thatd cause this problem

 

[Brian235]

its hard to say, sometimes shorting out a rca will kill the outputs, sometimes nothing happens. some headunits will run into problems unplugging rcas with them still on due to the voltage spikes.
some headunits fail over time due to vibration and dust, some are just cheap quality.

i would put the dmm on the power and ground into the headunit just to verify its a good stable 12v source, as well as the remote 12v in from the ignition. likely not a problem but id check

i honestly cant think of anything else thatd cause this problem

alright, thanks for the info the next time he comes over I will check it out if all else fails he is going to replace his hu