Beomaster 5000

31st August 2012

If strong FM radio stations give only mono reception (green ‘locked’ indicator illuminated but the green ‘stereo’ indicator out) the first component to suspect is the stereo decoder chip 1IC4 (TDA4500A). However, before replacing this it is worth gently adjusting the oscillator control 1R82 in both directions as this may restore stereo reception. If the stereo indicator then lights an approximate setting for the control can be determined by connecting and disconnecting the antenna whist noting which position of 1R82 gives the most rapid and reliable “lock”. The service manual gives a more accurate method if instruments are available. Note the position of 1R82 before commencing so that it can be returned to it if indeed 1IC4 turns out to be faulty. [Beomaster 5000]