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Horrible sound and static!

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  • Horrible sound and static!

    Today I put the carputer back in my car today for the first time in like 2 months. In the meantime my car has become cluttered with CD-R's...Anyways. This is with my new stereo system with amps and subs and everything, but I get static and horrible sounding music from my computer. I think it might be from my inverter for the PSU. If so, is there any thing I can do to isolate this, like a choke or something? Also, I have another really small inverter to drive some neon wire that's right next to my FM modulator. Could this cause problems too? Seriously, the tape adapter on a 89 factory stereo with horrible speakers sounded better than this. Thanks!
    Dudah's NEW site

  • #2
    the lights could most definatly be introducing extra noise... try it without the lights and see what happens.

    If that doesn't work, then ground EVERYTHING! the case, the power supply, the inverter... Typically, an inverter will introduce an audible whine or buzz... but this can usually be stopped be grounding and adding a "ground loop isolator" (Radioshack special: $15.99)

    Good luck,
    -Miles
    Near Completion: Intel P166 MMX, 32MB ram, 13GB Hard Drive, Keypad, 4x40 LCD. Sproggy MK2.6 ATX PSU. Win98SE with Winamp and Mark Zehnder Plugin. (Web-site: very soon)

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    • #3
      I'd imagine your neon wiring is the problem. The HV used for the neon lights will induce noise in nearly anything...
      Player: Pentium 166MMX, Amptron 598LMR MB w/onboard Sound, Video, LAN, 10.2 Gig Fujitsu Laptop HD, Arise 865 DC-DC Converter, Lexan Case, Custom Software w/Voice Interface, MS Access Based Playlists
      Car: 1986 Mazda RX-7 Turbo (highly modded), 1978 RX-7 Beater (Dead, parting out), 2001 Honda Insight
      "If one more body-kitted, cut-spring-lowered, farty-exhausted Civic revs on me at an intersection, I swear I'm going to get out of my car and cram their ridiculous double-decker aluminium wing firmly up their rump."

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      • #4
        yeah I would look at getting rid of the lights..... and get rid of the FM modulator..... ugh!

        for the inverter, dont get a ground loop isolator, do not pass go, avoid at all costs! What you can do (and what I keep saying and praising!) is remove the input AC filter circuit from your AT/ATX PSU since that will cause havoc with the inverters AC output. The filter circuit will buzz, and introduce noise into the system......

        http://members.optushome.com.au/magn...dware_psu.html

        give that a shot for sure.......
        Project - GAME OVER :(

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        • #5
          Will removing the filters work with a AT supply (i can't think of why not but i thought i better ask)?

          Also what should i do to make sure i don't kill myself removing those Capacitors?
          [SIZE=1]'91 Nissan Stanza

          [XXXXXXXXXXXXXXXXXXXX] XX% Completed -
          Car Totaled and i bought a 20G mp3 player

          http://machs-fuel.tk
          a DIY video projector page

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          • #6
            Originally posted by Machs_FueL:
            <STRONG>Will removing the filters work with a AT supply (i can't think of why not but i thought i better ask)?

            Also what should i do to make sure i don't kill myself removing those Capacitors?</STRONG>
            yeah it will...... um to avoid the killing bit, I had no troubles with mine (obviously) I guess leave the PSU a day or two to loose charge? can anyone suggest anything else?

            remember just capacitors BEFORE the bridge rectifier.....
            Project - GAME OVER :(

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            • #7
              Ground loop isolators are fine, and this might just be the solution to your problem, but usually these only help with ground loop problems which sound like engine whine. they wont fix anything else.

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              • #8
                if you want to remove the capacitors without killing yourself (not that it would happen anyways) just ground them, or hook a big resistor across the terminals. I guess this depends how big the caps are, but I've seen people even just short them out too ;P
                IN DEVELOPMENT -- '96 Mustang, lilliput with PII/450 laptop, custom DC-DC power supply, 60GB; Garmin GPS; 802.11g; compact keyboard, small graphical LCDs, OBDII.

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                • #9
                  The capacitors are a real danger, but since you are working before the bridge rectifier, you should be relativly safe as long as you don't go poking around. To be really safe, use a high value 1W resistor (like around 500K) to short out the terminals of the capacitors for about a minute. Don't use a screwdriver or something else, because the hugh surge current is bad for the tool, the terminals of the capacitor, and will probably take you by surprise.
                  Player: Pentium 166MMX, Amptron 598LMR MB w/onboard Sound, Video, LAN, 10.2 Gig Fujitsu Laptop HD, Arise 865 DC-DC Converter, Lexan Case, Custom Software w/Voice Interface, MS Access Based Playlists
                  Car: 1986 Mazda RX-7 Turbo (highly modded), 1978 RX-7 Beater (Dead, parting out), 2001 Honda Insight
                  "If one more body-kitted, cut-spring-lowered, farty-exhausted Civic revs on me at an intersection, I swear I'm going to get out of my car and cram their ridiculous double-decker aluminium wing firmly up their rump."

                  Comment


                  • #10
                    all right so im pearing inside my PSU and i have two big black Caps marked 220uF and what looks like 200V and a funny looking 4 pinned thing that has + and - marked on either outside pin and a ~ type line between the two inside pins..

                    What does a bridge rectifier look like?

                    the pictures on magnetik's page are a little on the blurry side..
                    [SIZE=1]'91 Nissan Stanza

                    [XXXXXXXXXXXXXXXXXXXX] XX% Completed -
                    Car Totaled and i bought a 20G mp3 player

                    http://machs-fuel.tk
                    a DIY video projector page

                    Comment


                    • #11
                      Originally posted by Machs_FueL:
                      <STRONG>all right so im pearing inside my PSU and i have two big black Caps marked 220uF and what looks like 200V and a funny looking 4 pinned thing that has + and - marked on either outside pin and a ~ type line between the two inside pins..

                      What does a bridge rectifier look like?

                      the pictures on magnetik's page are a little on the blurry side..</STRONG>

                      i know!! ****ty cheap arse digital camera! I appologies 4 that! the 4 pinned device u describe is the bridge rectifier..

                      two big black caps? are they marked with a negative stripe? cause on the AC side of the PSU they wont be...... in my case they were ceramic capacitors..... (disc type, non-polorised).

                      basically follow the tracks on the base of the PSU circuit board from where high voltage AC enters the unit through to the bridge rectifier, and remove all capacitors in-between...... !
                      Project - GAME OVER :(

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                      • #12
                        Any of you guys who don't know what the hell you are doing should stay the hell outta your power supplies.

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                        • #13
                          Stay outta the PSU, its prolly not causing the problem in the first place. And if your curious, the bridge rectifier IS that black square with + and - and two ~. Its just 4 diodes in a pattern, nothing more. Screw your PSU back together now, it wont fix the problem.

                          1st, get the interver for your neons away from the modulator. It would cause a high pitched whine/buzzing in the music. Just for kicks, try holding your cell antanna near the fm modulator and making a call :P

                          2nd, from what I hear, ground loop isolaters are CRAP, dont bother, just eliminate the source of the problem. Make sure everything is grounded, but not to the battery. Long ground wires usually cause problems too. Ground stuff to the frame, making sure to scrap paint off first.

                          I highly doubt that its the AC filter doing anything.

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