Need help troubleshooting amplifier

Discussion in 'The Projects Forum' started by SilvrEclipse, Apr 27, 2009.

  1. SilvrEclipse

    Thread Starter Active Member

    Nov 21, 2007
    58
    0
    I have a Blaupunkt PA2150 2 channel amp. Just recently it stopped working, I was hoping something minor was wrong so I took it apart trying to fix it. Im no electrical engineer but I have taken a basic circuits class so I am familiar with most of the parts. Anyways when plugged in the amp power led barely lights up, you can only really see it in the dark. There are also six RFP70N06 mosfets on the board that get extremely hot after the amp has only been on for a few seconds. One even has a little discoloration on the back side from the heat. This doesn't seem normal. Other than that everything looks great on the board. No burnt spot, the caps and resistors look great. Nothin else gets hot either. I have looked for a schematic of the amp but haven't had any luck. Was hoping maybe someone could help me narrow the problem down. Thanks
     
  2. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    Without a schematic or something it will be difficult to shed some light on the situation. It may just be a blown part or it may be multiple parts.

    The first thing I would check are the power supplies, if you can identify which parts they are. The mosfets may be from the power supplies or the output drivers.

    Here's some generic information from a web store about the device...

    Blaupunkt's PA2150 amplifier uses innovative Class "T" technology to produce incredible power and sonic fidelity, with very little heat. Low operating temperature means that the ultra-compact PA2150 fits just about anywhere — and it'll go in the tightest spaces without worrying about overheating. Since no heat sink is necessary, Blaupunkt's designers can house this stylish amplifier in sleek, modern-looking, lightweight plastic.
    Built-in crossovers send the right frequencies to the right speakers, and a subsonic filter eliminates energy-wasting inaudible frequencies for improved clarity.
    Details:

    • 150 watts x 2 at 4 ohms
    • 200 watts x 2 at 2 ohms
    • 400 watts x 1 in bridged mode
    • stereo or bridged mono output
    • Tri-way capable (Tri-Way crossover required)
    • Class "T" amplifier technology
    • MOSFET power supplies
    • speaker-level input adapters
    • 50-250 Hz variable high- and low-pass crossovers, 12 dB/octave
    • selectable subsonic filter at 10 Hz
    • remote gain control
    • 10"W x 2-5/8"H x 9"D
    • 1-year warranty
     
  3. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
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