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bad ground on inside of amp?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=37518
Printed Date: May 04, 2024 at 7:11 AM


Topic: bad ground on inside of amp?

Posted By: pimpincavy
Subject: bad ground on inside of amp?
Date Posted: August 16, 2004 at 6:19 PM

The power/protect light on my amp keeps blinking yellow and red. The amp will then only make the subs rattle, if i turn the volume on my HU WAY down the light goes back to green. When I wiggle the groud wire around ( on the end that is connected to the amp) the light will go back to green. If i shut the car off and come back later the amp will work fine. I know the amp is not overheating because the last two times it did this the amp was only on for a few minutes. Thw wire should be grounded good to the car, ive had it the same way for 4 months or so and have only recently started having problems. Is ther anyway the ground on the inside could be bad?? I know nothing about the internals of a amp, so any help would be great!

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Replies:

Posted By: customsuburb
Date Posted: August 16, 2004 at 7:10 PM
Are your RCA cables grounding out? Are all of your connections (power, ground, and rca's) clean and secure? Are any of these pinched anywhere? Try running a new rca cable and see if you have the same problems.

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Posted By: flynntech
Date Posted: August 16, 2004 at 7:53 PM

Anything is possible...

you seemed to isolate the problem by moving the ground wire...Is it connected well at the terminal? I have an amp that has no terminals for the power, they come through a gromet and are soldered directly to the board inside. Is this the type of amp you have?

Don't assume the ground is good at the body. The car has been vibrating and shaking for four months, plenty of time to free a poor connection.

If the ground at the body is bad:  Undo the ring terminal, find a good spot on the sheet metal to drive a couple of self tappers through without hitting the tank or lines, interior trunk metal is better if the screws don't go through to the outside (prevents weather corrosion) I also like to ground up top since I'm always encountering cars with water problems in the trunk area. shave some of the paint off with a small whiz-wheel, dremel...ask your girlfriend to do it with some 50 grit....what ever you decide to do, just get it to bare metal!! 

Now if that's not overkill enough, cut that ring terminal off...chances are that it sucks anyways. Get yourself a bare metal ring terminal of the correct gauge and ring diameter (it's ok to secure it with 2-3 tappers, it doesn't need to look pretty) Get gold, copper, whatever...it makes no difference to me. Crimp the terminal, get your open flame butane or propane torch, sweat the lug on there with some regular rosin core solder.  You can flux and tin it if that's your preference.....rosin core 60/40 or 63/37 is just as easy.  If you're real good with the open flame soldering, the insulation damage should be minimal....either way, that's what electrical tape and small zip ties are for, because that's what you are going to do anyways! You can shrink tube or fit a cable boot too, but tape and ties are always readily available.  

Both metal surfaces should be scuffed a little, add some dielectric grease and attach your ground with at least two self tappers. A star washer or two won't hurt a thing...

Now, this may sound like a redkneck install from hell, but I can assure you that when it is done under a panel or carpeting it makes no difference how it looks. Electrically, it will outlast the car.

If the bad ground is in the amp, again a small amount of 60/40 rosin core....but skip the propane, all you need is a 15 watt Weller pencil type iron here ;-)  

Best of luck,

FlynnTech





Posted By: pimpincavy
Date Posted: August 16, 2004 at 9:16 PM
Im going to try the RCA cable thing. I think something might be wrong with them, I can have only one cable plugged in (not sure if its pos of neg) and the amp will still work. This isnt normal is it? Right now its grounded to a screw on the back of the trunk. Thier is no paint and i redid the ground yesterday, i think it might be a little rusty though, so ill try and scrap the rust off. The problem comes and goes, so next time it happens ill try and switch out the RCA cables. If worst come to worst a friends of mines step brother is good at fixing amps, so I can bring it to him if its a internal problem.

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Posted By: pimpincavy
Date Posted: August 16, 2004 at 9:22 PM
I just read in another post that its bad to have the power wire running near the rca. Mine are running close to each other through the whole car. Could this be causing a problem?

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Posted By: customsuburb
Date Posted: August 17, 2004 at 9:59 AM
This would not cause the problem you described. If running a new set of rca's and a new ground don't work then take it to a repair shop and have them look at it.

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Posted By: DYohn
Date Posted: August 17, 2004 at 10:52 AM

Disconnect the speakers and see if the amp will power up and stay stable by itself.  If so, then there is nothing wrong with your power, ground or RCAs.  If not, then yes, it sounds like the amp is defective.  What is it and what is it running (make/model/wiring of amp and speakers)?

What has changed in the "last 4 months or so" in your system (or in your car for that matter?)  Have you added or taken out anything?  Have you adjusted anything?  Has the car had maintanance done on it?



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Posted By: kgerry
Date Posted: August 18, 2004 at 1:29 PM
it sounds like you could possibly have an intermittent connection inside the amp and simply by wiggling the ground wire/connection you are applying pressure to the PCB inside....what happens when you wiggle/apply pressure to the RCA connectors?  does the amp go into protect at lower volumes as well or only when turned up a bit?

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Kevin Gerry
Certified Electronics Technician
MECP First Class Installer

Owner/Installer
Classic Car Audio
since 1979




Posted By: xploder21
Date Posted: August 18, 2004 at 5:01 PM

 if the amp is the problem, it could be that any bouncing or shock absorbed by the amp could of loosened a solder joint on the pcb or it could of strees cracked a little and when it is shaken a bit it disconnects the tracer then returns to its rest position and completes the circuit.






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