Thump in player during power off, not ignition related.

It's been probably 3 years since i had to post a question about my Empeg! Just recently, when I was turning my truck off, i started hearing a thump/crack when the unit would power down. I checked in the FAQ and found something similar about the ignition causing a negative ground spike, so i decided to leave the ignition on and just power the player on and off by holding the top button in. Sure enough, it still does it, so I can assume it's not iginition related.

My player has worked without a single problem for the last 3 years, (i have had it for over 7 years and only had to replace the drives, add a resistor, add a capacitor and a few other small things..)

So, hopefully I can describe correctly what is happening...

When I turn the unit on, it powers up normally, and on occasion i hear static for about 3 to 5 seconds after the unit has been on for two or three minutes. I only hear this static one time per power on, its always less than 5 seconds in duration, its always very faint, and it never does it twice per power cycle. Also, now 7 out of 10 times i turn the unit off, i hear a thump with varying levels of loudness. It is not being caused by the ignition because i cycle the players power using the top button on the player. When i turn the player off, I hear an immediate thump in the right channel, then a secondary thump in the left channel about 1 second later. This is a "new thing" for my player that just started happening about a week ago. The only think I've done to my truck is had the air conditioner worked on about a month ago. I am thinking it's related to the internal circuitry of the empeg player because it doesn't do it "every time" i cycle the players power...

Any have any ideas if a cap or a diode could have gone bad inside the player? At first I thought it was the subwoofer doing it, but i totally disconnect that and then noticed that it was doing it in the right and left channels... It is a pretty significant thump/crack, and I can't help but wonder why i am hearing static sometimes too. I am perplexed...

Does the player go in to standby at all?

If it doesn't, you could have blown the fuse on the constant power lead (yellow). IIRC, Mk2 units will work fine (aside from not entering standby) with this fuse blown. Mk2a units won't power on at all.

The fuse is a 3 amp blade fuse which is usually purple.

If the player DOES go into standby correctly when you hold down the top button, then the next thing I would suspect before the player is an issue with the wiring or the amplifier.

First, let's make sure it's wired properly. What are the following wires (from the player harness) connected to?

Blue
Yellow
Orange
Black

What are the following terminals on the amplifier connected to?

Amp remote
Ground
+12v


Most problems with amplifiers making thump noises (or crackling which you say has always been happening) are due to simple miswiring of the amp and head unit. It might also simply be a faulty amp.

One way to prove this is to disconnect the RCA audio plugs from the amplifier, while leaving the power and amp remote signal wires properly connected. At that point, there should be nothing that the player can do to make it thump, even if the player is faulty. All the player should be able to do is signal the amp when to turn on and off. If the amp is thumping with the RCA's disconnected, there's either a serious wiring error or you've got a bad amp.

Finally, check for wiring problems on the docking connector.

Oh, and make sure there's not a loose screw in the player.

Rob,

When I hold the power button in for a few seconds, the player shuts down and the led glows, I guess that means it's going into standby? That is what causes the two thumps. When i press the power button again, it comes out of standby, so I guess it's workng correctly.

Tony,
Sorry to mis-explain the situtation, this thumping is new, it never did it before. It started about a week ago...

Never had any audio problems before last week, just a few misc things with dimmers and the like like...

Well, whether the static thing is new or old, look for all the same things I listed.

You still haven't answered about how the amp and player are wired up.

And when you say "the LED glows", do you mean that it pulses slowly bright to dim? If so, then it's correctly going into standby.

If that causes a thump WITH THE RCA CABLES DISCONNECTED AT THE AMPLIFIER END then you're very likely looking at a faulty amp.

Unless there's something screwy with the wiring.

I didn't answer about the wiring because I posted the message after the time I'm allowed to go play outside with my truck Not to mention I have to take my whole dash off to see inside

I will disconnect the RCAs after work, that's a good idea. I can only HOPE it's the amplifier!

As for the wiring, I will check that after I do the amp test. I haven't had a problem with it until just recently, so I suspect it is just my Kenwood's time to die. I guess if I spent seven years under a seat at 100degrees, I'd probably click and pop too!

It sounds like a problem with the amp to me, not that I'm an expert. I'd try just leaving the empeg on and remove the amp-on signal line from the amp and see if that causes a thump.

Well I finally had a chance to do some troubleshooting (in the rain) this weekend. I disconnected the empeg RCAs from the amp and powered cycled the empeg. It still made the noise, so I ordered a new amp. I'm replacing the old 2 channel kenwood with a 4 channel memphis mca 2004. Hopefully this will solve the problem.

I called the guy that installed my empeg and amp a few years ago. He said it sounds like an amp problem, but I should also check the amp ground wire (he said he ran it to one of my seat bolts), apparently there is a ground separate from the negative on the power section. I have to take my seats out to check that, so I figured I'll just order a new amp...

The RCA removal test (and thus the assumption that the amp is bad) is only valid if everything else is wired correctly. You never answered any of our questions about the wiring?

Sorry, I was just assuming it was wired correctly since the installation over 6 years ago has worked until just recenlty. It's only the last month that I started having the problem, so I was just assuming it was wired correctly since the beginning. I am to scared to take my dash off and undo the bundles of wires that have been sitting there for years to check what they are running to. I'm sure that it's going to bite me in the ass though. I'll probably wind up with a $250 amp that does the same thing as the one I have now, if it turns out it's wired wrong.

It's also possible for a wiring problem to develop over time. For instance, chafing, or the crimps coming loose. Doesn't necessarily mean it was wired wrong.

Definitly true. I'm going to start with the new amp (good excuse to buy one). Then if i still have problems, I will litterally have to pull the whole truck apart, but I guess it will be worth it

In case any one was interested in the resolution of this matter...

I finally got around to replacing my amp and all the bad noises went away