Free Shipping on Everything.
60-Day Money-Back Guarantee | Lifetime Tech Support

Alpine amp not turning off - draining battery

Car Audio, Video, & GPS

Car Audio, Video, & GPS
Talk about stereos, navigation, amps, subs, and all things car audio

Alpine amp not turning off - draining battery

  • This is a used amp (Alpine MRP-F240), and I'm suspecting that it is the problem. 

    The remote turn-on lead from the head unit is carrying a constant 0.6 volts even with everything switched off (+12V with head unit "on").  I've confirmed that all of these head units (Porsche / Becker) do this and that it shouldn't be a problem. However, when I attach the remote lead to the amp, the blue led light on the amp glows faintly and the amp will drain the battery over the course of a few days of sitting. 

    Amp has solid +12V from the battery and good ground.

     Otherwise, the amp and stereo perform with no problems.   Anyone have any tips or experiences?  Am I up for a new amp?

     Thanks!



    [edited by: rnd at 3:07 PM (GMT -5) on Thu, Apr 23 2009]
  • So with the remote line disconnected the amp stays off, but with it connected (and the car is off) the amp kicks on?

    Looks like your troubleshooting is solid. 

    Assuming the disconnecting the remote line does cause the amp to turn off, you could install a switch on it up near the head unit for ease of access.  Beyond this, I'd say that a new amp is in order.

    The TF-33's started the job, my car audio system will likely finish it.... the damage to my ear drums that is.
  • Exactly right - turns off when the remote line is unplugged.  I figure that I could use the switched +12V that the head unit uses.  But I don't know what's burned out internally in the amp, and if that may send nasty things to my head unit and/or speakers. 

     Bummer, new amp then...  Thanks for the reply though.

  • I'm not sure it's the amp.

    The 0.6V on the head unit seems like a problem to me.

    Perhaps the Alpine is not seeing this as fully off and that is the problem.  I would check with Alpine on this.

    The thing I am trying to avoid is you buying a new amp and finding out it doesn't turn off either.

    I think the power wire to the head unit would work, except then the amp would be on when the car was running and the radio was off (if it ever is, mine isn't).

    What I think you could maybe do is get a relay to go between the HU remote lead and a different 12V wire to the amp.  I doubt 0.6V would be enough to flip the contacts of the relay and it should be under $5 and easy to connect and also easy to test with a multimeter.

    Hope This Helps!!!

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs

  • TigerHeli:

    The 0.6V on the head unit seems like a problem to me.

    The thing I am trying to avoid is you buying a new amp and finding out it doesn't turn off either.

    Basically I was thinking of a failure in the amp using the remote line as a ground when the head unit is off.  Sounds weird, but many components will ground out a signal (through a resistor) when it should be low. This way they know the signal (12v in this case) is discharged.  A side effect of this, is that it can sometimes allow a signal to backfeed.  I only go into left field as I wouldn't think most amps would kick on with less then 5-10 volts. 

    rnd - Do you know anyone that might have a spare amp laying around that you could use to test in place of your current one?

     



    [edited by: Yel at 6:19 PM (GMT -5) on Thu, Apr 23 2009] [edited by: Yel at 6:02 PM (GMT -5) on Thu, Apr 23 2009]
    The TF-33's started the job, my car audio system will likely finish it.... the damage to my ear drums that is.
  • Yel's explanation makes sense to me.

    Yel - if the circuit in the amp failed where it no longer shunts a small remote voltage, I think my relay idea would still prevent it from essentially seeing ANY voltage, thereby solving the battery drain problem.

    So rnd can either get another amp or a cheap relay.

    Again, Yel - are you saying that the failed circuit could lead to backfeeding the signal so it is likely not a good idea to use the Alpine amp in any case?  (I took it that way, but just wanted to verify).

    Hope This Helps!!!

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs

  • The relay would work great actually.
    The TF-33's started the job, my car audio system will likely finish it.... the damage to my ear drums that is.
  • I had a similar issue with a car I had so I just ran a toggle switch to my remote on my amp, it worked out good. Before resulting to that I would suggest using a meter and checking your wires from your stereo with your ignition off, then with it on you should find a wire that put out approx. 12v with key turned and 0v with car off if so use that wire. I was told you can also use a wire going to your car speaker but when I tryed it I was unsuccessfully (not enough volts for a remote wire with my factory stereo) 
  • Wire going to the car speaker is a BAD idea.  Car speakers carry variable AC Voltage and you are looking for 12V DC.

    The switch would work fine also, the advantage with a relay is you don't have to worry about forgetting to turn the switch off and killing the battery - been there, done that more often than I'd prefer to admit.

    Hope This Helps!!!

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs