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Busted Cab?? Fried Board?? HELP!!!!!!!

Discussion in 'Amps and Cabs [BG]' started by alecmcmahon, Dec 30, 2001.


  1. hey guys, well heres the deal

    my uncle gave me his old fender bass cab he hasnt used in like 2 years.

    its a older model, (BXR something i belive) It has an 18 inch Peavey black widow on the bottom, and two 12 inch speakers above it.

    the top 12's do not work, there isnt any sound coming out of em... ( all the connecters are good, i checked) ..the black widow works..

    but the thing that really upsets me is that it is all distorted.. and really sounding like crap, i tried adjusting the settings on my head ( hartke HA3500 ) to get the nice clean bass sound i want... but no dice..


    he did mention the board in the cab could of been fried or something... i really dont know much about em.


    any ideas guys?? i really need to get this to sound good.



    ( how much does a new board cost? or to be fixed??)
     
  2. coooommmmmmmeeeeeeee onn, anybody got an idea??????
     
  3. JEZZ..come on, anybody have ANY IDEA at all.. im sitting here clueless... please help me out.
     
  4. hammong

    hammong

    Apr 11, 2001
    Sparks, Maryland
    Fender bass cabinets don't come with Peavey Black Widow 18" speakers. Something tells me that you're dealing with a cabinet that has seem some degree of "reconfiguration" by it's previous owner(s). Consequently, you're going to have to do a little bit of diagnosis and reconfiguration yourself to get the thing working properly.

    Step #1 - Determine if those 12" speakers are BAD, or if they're just not wired right. You can check to see if they're bad by measuring their resistance with a good ohmmeter. If they're "about" 2-16 ohms, they're probably good. If they're 0 ohms, they're shorted, and if there's no reading at all, they're burned out / open.

    Step #2 - What's this "board" you're talking about? I presume it's either a passive crossover or just some kind of junction board for the wiring inside the cabinet. If it's a crossover, it very well might be toast if the speakers in the cabinet aren't of the same impedance as the originals. Diagnosing a crossover requires some more elaborate electronic gear to measure inductance of the coils, and the capacitance of the capactors to see if they're in-spec, and to check the values, you need a schematic for the crossover board or well-labeled components on the board.

    That should get you started!

    FWIW: What do you mean by "distorted" when you talk about the sound from the 18? If the "board" is sufficiently mis-wired or the 12" speakers are open/shorted, you may be presenting your amp with a speaker load/impedance that is significantly out-of-range, and that could be causing your unwanted distortion. I would recommend NOT using the cabinet until you have properly diagnosed the problem, otherwise you risk damaging your amp.

    Greg
     
  5. well hammong


    i cant really follow step one .. .because well, how can i mesure the ohms of the speaker out put, if im not getting any sound out of them.

    the speakers dont look broken,..well, i dont know what a broken one looks like, they look like they just got right out of the box.


    and the sound sound im getting is distorted . i tryed just about everything on the amp settings to get it to sound right, with no luck.

    and the board, i dunno, my uncle said the board might have to be fixed or replaced , and something about the " dimods " , i dont know if i typed it right.. the thing im taking about it in the back of the cab were you plug your speaker cable into the back.. that thing.
     
  6. hammong

    hammong

    Apr 11, 2001
    Sparks, Maryland
    99% of the time, you can't tell a speaker is "broken" by looking at it. OHMS are a unit for measuring resistance or impedance in an electrical circuit. To measure ohms of a speaker, you need to purchase or borrow a "ohm-meter" or electrical "multi-meter" which is capable of measuring ohms. A "good" speaker will measure between 2-5 ohms for a "4-ohm" speaker, 6-10 ohms for a "8-ohm" speaker, and 14-18 ohms for a "16-ohm" speaker. The speaker's ideal resistance is almost always printed on the sticker on the back of the speaker or stamped into the magnet on the back of the speaker.

    Those things you plug your speaker wire into are called "jacks". I have no idea what a "di mods" is.

    It sounds like you might need to take the speaker cabinet to a shop that has expertise in repairing speakers/cabinets if you lack the proper tools or expertise yourself to correct the problem. If you were local to Maryland and could bring it by, I'd gladly look at it myself for you.

    Greg
     
  7. ill try to get some pictures tommorow to explian in detail........thanks.
     
  8. Bassstud1

    Bassstud1 Supporting Member

    Sep 23, 2001
    LaPorte Indiana USA
    Hey Hammong I wonder if what he really hass is one of those old peavey cabs with the 18 and (2) 10's. If so he would have a bi amp style crossover. Perhaps he is using the low end in put only? Just something to think about.
     
  9. well bassstud... i dont think its a peavey cab...well cause.. it says FENDER all over it, on the cover, on the back....

    and im using the " middle range " there are 3 jacks on the back.. the high range dont work, but the low , and middle do.


    it SORT of looks like the picture im attaching, but it doesnt have the grids over the speakers.. but that is what it looks like.
    ( and its a diffrent head)
     
  10. AlecMcMahon,

    With all due respect, you don't sound like you are qualified to diagnose and repair the cabinet. That bad sound you hear could be a blown speaker, rubbing voice coil, rattling cabinet, etc. The problems with the 12's is probably a blown resistor on the crossover board, or a bad switching jack, or a bad solder joint, or an open speaker coil, etc. Too many variables.

    Take it somewhere to have it repaired professionally. That's my advice. You may spend lots of money and time replacing parts that aren't even broken if you just start shotgunning parts (shotgunning parts is when a tech just starts replacing everything trying to solve a problem).

    Chris
     
  11. oh yes, i know.. far from it :)

    yeah, im gonna try to get it over to sam ash see what they can do..

    how much do you think it would cost for them to fix it up real nice?
     
  12. I'd guess the usual $50 bench charge, even if all they do is say, "Yeah, you're right, it's messed up somehow. Pay the cashier on the way out."

    In the meantime, do some research and you CAN learn how to fix all this stuff yourself. Then you'll be the guy saying, "Yeah, your're right, this thing is broken. Now you owe me $50 for my diagnosis." :D

    Seriously, if you're into this sort of stuff, learn it and you'll be set for life. Electricity is where it's at.

    Chris
     
  13. funny, my father is an electriction ~

    lol...