Fired up my DEH-P4500MP and no sound from the 4 mains...All sub and bass, but no main audio. HELP!!!
What in the world could cause this? It was fine the other day when I shut it off...then today all whummm...whummm.

 

I had a similar problem with my home setup. All high and mids, no bass. If you left the volume up when you turned the system on, maybe you killed the speakers with a power surge. Or just check the entire gig for a short.

 

Are they on a seperate amp or just running straight off the deck?

 

Thanks guys,
Speakers in stock locations, running off the HU only.

 

well since their directly wired to the deck, that pretty much only leaves the one culprit...

I would say your deck took a dump on ya.

Oh well, perfect time to go buy that $6000 cd/dvd in dash tv, and xbox under the seat fancy setup you've always wanted

 

So would the internal amps be fried?
Obviouslly it is sending the signal still (since mu sub is powering up). Would an external 4 channel power my mains? and get by?

 

I would say somethings gone wacky with the internal amp.


I very highly doubt the use of an amp on the mains is going to work unless the deck is still putting out a signal. Highly doubt its possible.

It could work if the deck has a set of rear out RCA's. If they were still operating you could run both the front and rear speakers on a 4chnl amp hooked to that. It wouldnt sound good but it would get you by...


Why not just swap the deck out?

 

holy ****! same thing happened to my gd deh4700 lastnite. its been in for about a year with no problems. my four speakers just stopped playing, sub still going... this morning it worked up until i hit a small bump... i meant to go check the plug on the back but i lost my little side tools. i dont think the plug is the problem because my hu is always lit up and keep memory. what u guys think??? btw i didnt mean to hijack your thread.

 

s'okay dude...anything to get some answers.



84z...Yes it does have another set of rca's sorry for not clarifying, I'm picturing it in my head, and not putting it on paper.


I really wasn't into blowing two bills right now. I do have an old 40w Pioneer 4ch. kicking around.

 

I had this problem before, it was a loose wire if I remember corectly.

 

I've had a similar problem before on my daily driver. One of the leads to the speakers was shorting out on a door frame and causing my H/U to go into a protection mode. The sub pre-out was still sending signal to the amp too.

Also try the reset switch on the H/U if it has one. (I'm not familar with Pioneers.) Sometimes these things "flake out" and stop working in strange ways.

 

i was thinking mine was going into a protective mode, im fimiliar with this from an amp that would kill itself with a blown sub. anyway, i forgot to mention if its fairly quiet around i can hear my speakers pop one time when i turn the key on... so i thought it might be a shorted wire.

i was told the easiest way to check the speaker wires was to pull the hu, unplug it and test resistance to ground on all the wires. should this be a safe way of checking??

 

Could be a couple of things.
Lets start with how you made you're connection?
One of the speaker wire could be shorting to ground or another speaker wire. One of you speakers could be bad, effectively shorted. On the bad end of things the internal amp in the HU could have dumped. It's Pioneer week point, the amp IC. They are a little temper-mental. There could vary well be a problem with the install that caused the amp IC to quit. If the HU has out outputs you should be able to use then and an amp.

All of the pre-amp outputs come right out of the EVTC IC, before the amp, or 'pre-amp'. That's why the sub outs still work and why the other output should still be working.
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Just read this part. Sounds like you have a bad ground in the system the killed the amp IC.
Do you have an ohm meter and know who to use it? If so you NEED to check the RCA grounds. If they are open you have a bad ground somewhere and NEED to find and correct it.

 

yes and yes. i have one and know how to use it. so testing my rca grounds can show a short in my speakers? by rca, do u mean the red and white plug-in connectors, or am i misunderstanding? thanks needaz...

 

Sorry, I forgot to describe in my first post that an audible pop is exactly how I knew my H/U was going into a short-out protection mode. I'd check your speakers leads to find which one is grounding out.

 

First, Jade Gray is right. Sometime with a speaker wiring problem can give you a pop. So before we get in to the RCAs it is best to go over all the speaker wires first. Unplug the HU and measure the resistance of all 4 speakers, should see around 4 ohms. Then check the resistance of all 8 speaker wires to chassis ground, should be open (infinite resistant). Don't put the ohm meter anywhere near B+.
Yes, the RCAs are the pre-amp outputs. That style plug is an RCA. The outer jacket is the ground. Measure the resistance from the outer jacket to the metal chassis of the HU. This should be 0. If not, theres a problem.

 

well...went out determined to figure out my issue with the head unit, and...NO ISSUES!!!! I mean absolutely NOTHING!!!!! Every channel working....every mode working on every channel. Not sure what happened to it, but everything SEEMS fine. I will watch closely in the next few weeks. hope it was just a fluke.
(I even shut it down and fired it up a few times, started the vehicle, moved it, shut it off... all before I posted just to see if it was something simple.)

 

i dont mean to burst your bubble or anything............ BUT mine worked on and off this whole time 90% off though. (i didnt mention this because it would complicate your thread). and i think yours will go off again.

anyway i did what needaz and the guy at my audio shop said to do. and turns out my rear pass speaker wires showed a big fat 0.00 when i tested the continuity of the wire to ground. this was the speaker that is making the loudest pop when first turned. then i remember that my dumb @ss was pist the other day working on my pass doorjam switch and i pulled on a few wires. the blue and striped blue wire behind my kickpanel were the ones i lightly yanked. ima just runa new wire from hu to speaker, playing it safe.

needaz, thanks for your help; and kevin g, good luck man.

 

It's a loose wire, if it was the internal amp then it wouldn't be putting out to your amp(s)... It's feedbacking and making them not work.

 

Sorry, but not quite. The pre-amp output branches off between the EVTC (Electronic Volume and Tone Control) IC and the amp IC. So even if the amp IC was bad, there would still be signal out from the pre-amps, just like there would still be signal at the input of the amp IC but no output from the amp IC.

Still could be a loose wire, you'd still have output then too.