VERY Strange amp power problem

Discussion in 'OT Technology' started by Professional Slacker, Jul 11, 2002.

  1. This is by far the strangest thing I've ever come accross in my car audio days, and I can't fix it! HELP!

    For some reason my amp will not power on. I have the power running from the battery, to a distribution block and then to a 1 farad cap and then to the amp. When I had my Rockford Fosgate head unit it it worked fine, then I took it out for like a month and just yesterday put back in my old Panasonic deck. Now the amp won't power on. I know its not the deck cause I had the panasonic in there before with the exact same setup before the RF deck and it worked.

    But thats not the strange part, the strange part is that when I go take the fuse out of the power wire coming off the battery, the amp powers on and bumps for a second! (Running off the 1 farad cap). But then the cap looses its juice and the amp powers off again.

    I have my remote wire going to the sub amp, the crossover amp and the four channel amp so I was thinking maybe it didn't have enough juice to turn them all three on so I just wired it to the sub amp and nothing else and that didn't help.

    I also tried removing the cap and just running power straight from the battery to the amp and no luck.

    I checked all the fuses and they are all fine.

    Checked the ground. (Although the protection light would turn on if it was just a bad ground but it was getting power)

    I even thought maybe the RCA's weren't putting out juice (and for some reason the amp won't turn on unless its getting input, which makes NO sense but I figured I'd try) and so I plugged the RCA's from the four channel amp (which works) into the sub amp instead and still no luck.

    I don't know what else to do!

    It only works when the fuse in between the battery and the cap is removed, the amp DOES turn on and the subs DO pound for like 3 seconds until the cap runs out of juice, then when I put the fuse back in it doesn't work, but I know its getting power cause its obviously recharging the cap.

    I JUST DON'T GET IT, PLEEASSE HELP ME!!!

    -Ryan
     
  2. M-1000

    M-1000 COME FLY AWAY

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    dieing battery :dunno:
     
  3. flynfrog

    flynfrog Cool isnt Cheap

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    bad rem?
     
  4. REM?

    Whats a REM?

    I just bought the battery a few months ago, optima red top. I hope its not the battery! I'm going to try to test the power wire with a multimeter to see if its gett 12v. I'm thinking maybe its getting really low voltage, which would be enough to charge the cap so it would run on that for a few seconds, but not enough to power the amp *boggle*.

    -Ryan
     
  5. LegendTodd

    LegendTodd Guest

    Have you checked all your connections at the head unit? Maybe the remote wire is loose which is what i believe flynfrog was trying to point out. Sounds like there was some sort of error in the installation. Good luck keep us posted.
     
  6. Alright well I used the multimeter and verified that its getting a constant 12 volts, I also verified the remote wiring is giving a constant 5.8 volts. I also double checked the fuse, and the ground. At this point I think the amp is at fault.

    However, I don't see how this could be for the following reasons.

    1. It worked before using the exact same setup, nothing has changed.

    2. It works when I put the capacitor between the battery and the amp then remove the fuse between the cap and the battery. Mind you it only works for a few seconds until the cap looses power but it DOES work, and the subs DO pound.

    I'm really at a loss here, I've checked and double checked all connections, I've tested everything for power, including the RCA's, I've tried everything I can think of short of putting the fused inside the car instead of under the hood and just pulling it every three seconds hahaha :(

    -Ryan
     
  7. Mister Mac'

    Mister Mac' Av: Daniela Denby-Ashe in Torchwood S1Ep7

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    The signal ground may be floating? I've had a similar problem, and in my case it was because the signal ground and power ground are completely isolated and the signal cable must be grounded at one end for it to work. :dunno: I doubt that's your problem though. Does the amp have a power LED? if so, does it come on at all?
     
  8. flynfrog

    flynfrog Cool isnt Cheap

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    try taking it out of the trunk get a few short pices of wire and hook it directly to the battery and jsut run a jumper wire form teh battery to teh REm on the amp see if it comes on then

    you do have polarity corect dont you
     
  9. Ok, whats the difference between a signal ground and a power ground? I'll try that once I know what it is :)

    I am going to go take the amp out of the trunk and try hooking it directly to the battery. Is it going to be ok if the remote wire gets 12v to it? When you say use a jumper do you mean just hook the positive from the power wire going to the amp into the remote input?


    I SERIOUSLY appreciate everyone taking all this time out to help me.

    Thanks again,
    Ryan
     
  10. 04

    04 Guest

    I would say you probably have the amplifier installed incorrectly. It could very well be broken too. Make sure you have power wire running from the battery to the amplifier's B+ or power terminal. For testing sake, run a small gauge jumper wire from the B+ to the REM wire so that the amp should constantly be on. Also make sure you have a good ground connection. Perhaps you installed the capacitor incorrectly, wiring it in series with the amplifier, which would block DC power, and removing the fuse allowed the cap to ground itself :dunno: . You should have the capacitor with 3 wires going into it. One wire on the negative termanal going to the chassis ground and the other going from your cars battery to the cap, and also to the amplifier.



    Or, you have a really wierd amplifier! :ugh2:
     
  11. Thank you for that input, I now realize I had the cap wired incorrectly. I'm thinking for the month I didn't have a deck I must have fried my amp some how. Although its strange it turns on and makes the subs pound for a few seconds. My last resort is going to be to try a different ground and then run a jumper for the remote wire. I'll probably do that tomorrow and give you guys an update. I'm thinking it probably won't work but its worth a shot.

    Thank you again everyone,
    Ryan
     
  12. flynfrog

    flynfrog Cool isnt Cheap

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    12 votls is ok on a rem
    most gusy run a relay setup with more than 2 amps more can hurt your deck
     
  13. 04

    04 Guest

    Yeah, that was my guess. I presume you had a wire running from the battery, to one terminal on the cap, then another wire running from the other terminal to the amplifier. What this caused was the amplifier running in series with the capacitor. This is a problem because what capacitors do is block DC current. I dont even think a capacitor would pass ANY DC. I could be wrong though. The bigger the capacitor's value in farads, the lower frequency it would permit to cross with less attenuation.

    When you removed the wire on one end of the capacitor, the amplifier saw a DC power source, and was able to play for a few seconds. Here is how you fix the problem. On the positive terminal on the capacitor you should have 2 wires. One going to the battery and one going to the amplifier. On the NEGATIVE terminal, you should have one wire going to ground, same as the amplifier's ground. Try it then, it should work fine.

    P.S. My opinion on capacitors is that they really arent that helpfull in the case you are using them for. They can help filter the power and do provide SOME voltage stability. But, if your charging system cant handle the demand, the capacitor is not going to help for long....
     
  14. ItzLoud

    ItzLoud Guest

    take the amp out and get some speaker wire. go to the front of your car and screw in wire to the REM and + and wrap it on the + post of the battery. then do the same for the - . if you get nothing... then its the amp. try a different amp in your wiring and see if it turns on.
     

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