Is there a way to test an amp?

[bkearney]

We tried to play some music on the water the other day, and nothing worked. I went to check it tonite and noticed that the rca cables from teh head unit to the amp had melted. I replaced them with whatever was lieing around hte house, and the sound is muddled. Is there a way to test if I have hosed the amp? I noticed some rust on the outside, so it may have gotten wet. also, the ground on the battery is very hot.

--bk

[David Analog]

Yes, but past a basic operational test you are going to need some help. To know if the amplifier is up to spec, you should send it to either the dealer you bought it from or to the manufacturer via the dealer.
From your comments it's not looking good. The warm battery ground is really a concern. It takes a ton of current flow to warm a 4-gauge cable.
If you know that an amplifier has gotten wet, from a storm or roller, then kill power to the amplifier ASAP and do not turn the amplifier on again until it has been properly inspected and reconditioned. This is the only way a water-damaged amplifier can be saved. Although it is tough when you don't discover water exposure until later.
Hopefully the amplifier and supply line are protected via a fuse or breaker.

[MLA]

the ground on the battery is very hot.

This also peaks my interest also. So there was a noticeable temp difference between the GND and POS? Was this the battery ground or amp ground?

[bkearney]

This also peaks my interest also. So there was a noticeable temp difference between the GND and POS? Was this the battery ground or amp ground?

The amp has a set of wires that go straight to the battery. There is an inline fuse on the positive wire. The connecttion at the battery on the ground side was very warm, and the positive was not.

[philwsailz]

IF the RCA cable melted, it is likely that the amps ground wire is seeing a very high resistance, and if the battery terminal is hot it is likely there; bad crimp, corroded connection or loose connection; something like that.

What happened to the RCA is this: the amp is using it as a ground conductor; as the ground portion of the amp's power wiring. That means the head unit is ALSO being used as a ground conductor, so you better check the head unit's ground wire to make sure it hasn't been damaged. I have seen this first-hand, in a boat plant. A guy removed the ground wire from a big amp while it was on and playing, thinking he could turn off the amp that way. In this instance, it didn't work as it became obvious the RCA shield conductor was also tied to the amp ground. the amp stayed on, but the current being carried by the ground wire was redirected to the RCA cables. The amp didn't like it! Luckily it didn't run but maybe a second before the amp sense under-current/under-voltage and went into protect.

The fix for you on the wiring is to go and clean up the ground wire and all its connections, from amp to battery. Find the loose section, or the corroded section, or the dirty section... It will probably be obvious. Fixing the ground situation MIGHT get the amp going. There is a chance it will fix things, but it is only a chance.

If fixing the ground wire problem doesn't take care of it, you probably ought to remove it and get it to a bench at an audio shop where it can be properly tested

Phil
Kicker

[David Analog]

All VERY good points made by Phil. Something to add...
Most, but not all amplifier topologies, use an 'above' RCA ground that has no DC link to the power supply ground. The isolation impedance might be 10Kohms. Yet, at that very high impedance, and in consideration of the battery potential, current will flow. In order to be free of a ground loop, and avoid noise, the audio system references the HU RCA shield as the singular location for a true chassis ground. So if there is something wrong with the amplifier ground path and it has used the RCA ground shield termination as a substitute, then the HU is likely damaged and you'll probably need to add that to the repair list.

[bkearney]

I ended up taking it by a s sound dhop, and they were able to isolate it to the head unit being blown. They could not tell me why the RCA cables melted, but htat vibration could cause that to happen. The head unit was 8 years old, so even the cheapie new one is much better. Now, I am off to search the forums about the best way to add a round remote control into that oval shape my 2003 has.

[MLA]

You need to heed the above advice from Phil and Dave. the blown head unit was what we call and effect, not the cause. Likely blew due to the ground load, but likely was not the cuase. Replacing it and the RCAs likely addressed the symptom, leaving the root cause to pop up again.

Along with a bad crimp or corroded cable end, how many cables are on that battery ground post and how are they stacked?

[David Analog]

the blown head unit was what we call and effect, not the cause. Likely blew due to the ground load, but likely was not the cuase. Replacing it and the RCAs likely addressed the symptom, leaving the root cause to pop up again.

Along with a bad crimp or corroded cable end, how many cables are on that battery ground post and how are they stacked?

^^^Spot on.
I don't buy into the RCA cables melting because of vibration.
There is nothing inside a HU that could melt the RCAs.
The RCAs likely melted because of one or two reasons. They were physically connected to or next to something that got very hot, or (and more likely) passed too much current as a substitute ground path.

[bkearney]

This is my setup... I don't see any issues. Do you guys?http://uploads.tapatalk-cdn.com/20160731/ae87f7499ef4dff385d15c376424ee16.jpg

Sent from my SM-G925I using Tapatalk

[MLA]

Your fuse holder would serve you better if its was a little closer to the battery POS terminal. Also, is there a master on/off battery switch?

Is this the suspect ground that was warm? Whats it look like under the insulation?

http://i12.photobucket.com/albums/a217/mikesliquidaudio/ae87f7499ef4dff385d15c376424ee16V2_zpsvwzznbsn.jpg (http://s12.photobucket.com/user/mikesliquidaudio/media/ae87f7499ef4dff385d15c376424ee16V2_zpsvwzznbsn.jpg .html)