Sorry in advance for the long post. I have a '94 S-10 Blazer that the stereo was finished in about 3 weeks ago. It consists of

Pioneer DEH-8MP Head Unit
Planet Audio P5 5 1/4" component in kick panels up front
Two Memphis M3 12" Dual 4 ohm voice coil in ported box tuned to Memphis specs
Memphis PR100.4 to front component
Memphis PR1000.1 to subs (wired in 1 ohm load)

Everything was fine with it until today. I was on my way to work listening to a cd when I turned up the volume to about 25 it got alot of static in it as i was turning it up and sounded as if it was playing at a volume much lower. So I took the cd out thinking something was wrong with it. I turned it to XM while I was cleaning the cd and my subs weren't working (Everything else was fine). Turned the volume up and the highs/mids sounded fine. I drove for about another 10 minutes with it a low volume and when I started turning it up the same thing happened and my front quit playing. So I cut the headunit off. As I pulled up to work I tried the regular radio and the highs/mids worked but as soon as I tried to turn it up at all the same thing happened again and they quit playing. I really haven't had time to pull the headunit and look at it since I am still at work but I was wondering what might cause this. All the wiring looks good on the amp connections. Once again, sorry for the long post and thanks for any help given.

 

Your probably over heating your amplifiers. Most amplifiers will reduce the ouput in order to reduce the temp. When the temp goes down it will work normal again. Check the temp of your amps when it does this. If they are hot you need to provide proper ventalation. Fans are an option.

 

I thought the same thing with the sub amp but the protection light wasn't on. When the same thing happened to the highs/mids it had only been played at low volume for about 10 minutes or so. I just when out there and I have power to everything, everything on the deck works but no sound. Maybe something came loose behind the headunit or just a bum headunit?

 

I can think of two things that I would check, if both the amps turn off when you turn up the volume, [no sound out of subs or speakers] I would check the output on the HUs amp control lead, [blue/white] you can check it at the amps turn on term., [is there 12V+ there] another thing I would look at is, shorted out speakers or speaker leads, if it was not both amps I would say that a shorted speaker is definitely the problem, but that would mean there would have to be a short on the subs wiring also. [and you say the protection light was not on] the other thing I would check is the fuses on the power cables for the amps. BTW how do you have them wired and what are you using for power wire and fuses, [gage of wire, type and amperage of fuses? 94

 

The subs are wired parellel (DVC 4Ohm) so the sub amp is seeing 1 ohm (amp is stable at 1 Ohm). The mid/highs amp is stereo. I have 4 gauge power wire run throughout the vehicle. I considered the possibility that it was a fuse on the amp when the subs quit but I doubt that is the issue being the same thing happened shortly after to the other amp also. The underhood fuses are ok. I'm wondering if maybe the something came loose behind the dash being that there is a bunch of wiring pushed in behind the headunit or maybe I just got a bum headunit from Pioneer. I'm going to check it all out in the morning and see what is going on with it. Thanks for the help.

 

I fixed it today. I noticed that the power would only stay on for a few seconds on the amps. I checked the voltage at my amps and it was only 5.4 or so. I then checked the voltage at my extra battery and it was about the same. At that point I figured I must have blew a few under the hood. The fuse under the hood wasn't blown by looking at it but I replaced it and it worked fine. The extra battery was trying to charge the whole system and only had enough power to sustain it for a few seconds. Thanks fcm and nsxxtreme for the swift replies.

 

Do you have a battery isolator and all that good stuff?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C_EJ8 &raquo;</TD></TR><TR><TD CLASS="quote">Do you have a battery isolator and all that good stuff?</TD></TR></TABLE>
I sure hope not unless he has upgraded the alternator. 2nd battery isn't a good idea either unless the alternator has been upgraded.

 

No I don't right have an isolator right now. I don't play the stereo without the car running (just a daily driver). I have a fuse inline at the extra battery in case of some sort of problem. Upgraded alternator is probably the next thing I plan on doing but the stock alternator (GM option 140 amp) was put on less than six months ago. It is charging fine for now but HO alternator is a future upgrade.


Modified by smalltownVA at 5:51 PM 8/4/2005