Altec Lansing ACS621 resistor color code

By mayooman ยท 7 replies
Mar 2, 2013
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  1. Need to replace r29 & r30 resistors that were burnt beyond recognition, but have had no success in locating schematics or color code. Found a picture of the board online but to small to identify bands. Any help would be appreciated!
  2. jobeard

    jobeard TS Ambassador Posts: 11,155   +985

  3. jobeard

    jobeard TS Ambassador Posts: 11,155   +985

    Likely a cross-over network and frequency dependent.

    A simple design [​IMG]

    Here's an intro to the subject of crossover networks

    If R1 connected to C1 is burnt, then the POWER rating (of the resister) was too low for the inputs and you should suspect that C1 needs to be replaced too. R1-R2 is an L-PAD (ie variable with a knob) and used to adjust the cut off frequency.
  4. mayooman

    mayooman TS Rookie Topic Starter

    Thanks for the info J.O.
    I'm assuming its an L-Pad because it has a volume control and 2 burnt resistors of the same size. My dilemma is figuring the resistor size, (ohms, volts, etc.), without having he color bands as a guide. I'm a novice at electronics repair and was asked to look at it by my nephew. I included pictures of the board top & bottom. Black area on underside is were the resistors were positioned and top immediately left of the two capacitors. Is there a way I could calculate the resistor specs from the capacitors?

    Attached Files:

  5. jobeard

    jobeard TS Ambassador Posts: 11,155   +985

    Yes - -depends upon the 'cutoff frequency' - - OMG, haven't done this in 30+ years so give me a frequency you want and and the numbers on the side of the capacitor and (gulp) I'll rummage about to find the equation . . .
  6. jobeard

    jobeard TS Ambassador Posts: 11,155   +985

    Btw: those pictures are for an ACTIVE cross-over, not passive as I showed in post#3

    Your best bet would to look for the part-number on the pc-board and the google for a replacement.
  7. jobeard

    jobeard TS Ambassador Posts: 11,155   +985

    If you can't find a replacement, then get the nephew to build two of these as a total replacement for the active circuit
  8. mayooman

    mayooman TS Rookie Topic Starter

    Hi J.O.,
    Couldn't find any replacement boards so my nephew will have to build his own.
    Thanks for all your help!

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