well one day i was driving and my head unit just started smoking. it still works fine though. after that happened i lost all power to my amp. i checked my back up fuse and all others and they're all ok. my driver side speaker quit working also. bad groudn mayb? do i have to take the whole dash out to get to the harness?any ideas guys? TIA

 

Well if there was smoke, there was a problem, I would pull the HU and start looking for what burnt, maybe the RCAs if you lost ground on the amp it would try and ground through the RCAs. 94

 

Smoking, that sounds like a bad ground in the HU. Youre gonna have to pull it out and check that... I'm voting bad ground

 

so i bad ground will cause my amp to lose power?

 

Pull the deck like said above and see. Make sure your amp is getting it's constant(check underhood fuse), Check the amp ground.

Make sure your blue/white wire(remote turn on is still hooked up) That wire probably grounded out(poor routing) thus smoking thus your amp not working but your deck still works.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Andrew12 &raquo;</TD></TR><TR><TD CLASS="quote">Smoking, that sounds like a bad ground in the HU. Youre gonna have to pull it out and check that... I'm voting bad ground</TD></TR></TABLE> It is not a bad ground in the HU, [a bad ground for the HU would keep the HU from working, it would not produce smoke, it may have been a bad ground for the amp

A poor ground on the OPs amp would keep the amp from working, but because grounds are "common" on a lot of car audio the amp ground is "common" with the RCAs "signal return" or the signal neg.(-), [the outside barrel of the RCA plug] that connects to the pre-amp output part of the HUs printed circuit board and is designed to carry about a 500mA - 1A, [1/2A - 1A] load.

Now if the amps ground, designed for a, say 50A load, goes bad the amp will "look" for the ground from anyplace it can get it, in this case it would be the 1/2 amp limit trace on the HUs circuit board, it would heat up to melting point in about 1 sec. produce a bunch of smoke, [from the HU] and the amp would no longer work, even if you fixed the amps ground as there would no longer be a signal return, [neg.(-)] on the HUs rca outputs that the amp was connected to.
laocivic
To test for this, plug the RCAs into another set of RCA outputs on the HU, if it has another set, don't forget to check the amps ground before you try this or you will see smoke again.

BTW what is the make and model of the amp and HU?
Where and how is the amp grounded?
How long is the amps ground lead? 94

 

its an old dual HU, rockford fosgate amp 900 watt. The ground wire is grounded on the the struts for my rear shocks. i had a 300 watt amp before that then i switched, but only changed the power wire to hold more power. should i have changed to ground too? but it worked for so long wiht no problems.

 

The amp ground should always be the same or thicker gauge as the power lead.

Have you checked the ground? 94

 

so i guess ill just get a thicker ground wire to match the power, but what makes my HU lights stay on after i turn the car off? the radio isn't working or anything. the lights just stay on

 

Although you should replace the amp ground, it has nothing to do with why the HU is staying on.
Your HU has obviously bit the dust, once the smoke gets out there is no way to get it all back in.

The reason the HU stays on is probably because a diode between constant 12V+ and switched 12V+ is blown.

Have you pulled the HU and checked the wiring yet, to make sure there is not short(s)? 94

 

alright ill check that...so you say its over for my HU. but it still works like normal...why?

 

The HU may work alright but the preamp outputs, [RCAs] are what are damaged, [if trace's are burnt] so no signal to the amp. 94

 

alright...i guess ill just get new wiring for the amp and a new HU. thanks for the help i appreciate it