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Help me fix a broken amp!

Discussion in 'Amps and Cabs [BG]' started by csm672, Mar 14, 2009.


  1. csm672

    csm672

    Nov 2, 2008
    Tulsa, OK
    Before anything else, I know this amp isn't worth repairing... But it's my nephew's and broke when I was borrowing it. So, it is a Drive CD200B 20 watt solid state 8" amp. I think the transformer went bad. I can't get a reading on the secondary side on any wires. Problem is, I have no idea what to replace it with. I can't locate a wiring diagram for it online (probably because it's so cheap) and there are no markings on it to indicate what it should put out the back side. Is there a universal range I shoulf be looking for? Thanks in advance for any help
     
  2. SpamBot

    SpamBot

    Dec 25, 2008
    St. Paul, MN
    Just spend the $60 to buy him a new or similar amp. Trust me, replacing a transformer will cost at least that much, unless you find a similarly spec'd one in an old TV or something...
     
  3. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Check the fuse. Unfortunately, the amp probably uses a custom power transformer, or something from an offshore supplier that does not have a published part numbering scheme.

    If you can figure out some things about the circuit, you could make an educated guess about the transformer voltage. Of course doing so is not without risk.

    What's the power amp circuit look like? Does it use an IC power stage? How many wires are coming out of the secondary of the power tranny?

    The other issue is that if the tranny went down, something else probably took it down.
     
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    On second thought, +1. If it's that cheap.
     
  5. csm672

    csm672

    Nov 2, 2008
    Tulsa, OK
    Thanks for the fast replies! The transformer has 3 wires coming out the secondary. No chips, just all caps and resistors. The transformer couldn't be much, it's tiny. The secondary had continuity between the wires, so I'm thinking that may have done it in. I understand about buying a new one, but I would like to try and fix this one first. Any more help? Thanks, Casey
     
  6. Stromrider

    Stromrider

    Feb 16, 2008
    CT, USA
    The secondary should have a fairly low DC resistance, as should the primary. Low, like 3-20 ohms, not 0. Three wires means it's probably a center tapped transformer.

    If the fuse isn't blown double check and make sure you get 120Vac across the primary. Be extremely careful measuring line voltage.
     

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