Beomaster 8000 Repair: Volume Control Issues
Beomaster 8000: A dead AD7110 volume attenuator needed to be replaced.
The Beomaster 8000 uses Analog Devices AD7110 digital audio attenuators to control the output volume. These attenuators are controlled by a six bit bus driven by one of the microcontrollers. This results in 64 output volume steps, of which 60 are used (hence the 0-6.0 volume range). The control range is 90dB, i.e. each step corresponds to 1.5dB volume change. If the volume control exhibits reproducible failures at certain volume levels it is likely that one of these attenuators is failing, or a bad contact interrupts one or more of the six control lines. Replacement of the chip or cleaning of the contacts is usually a successful remedy.
Please, visit these blog entries at http://beolover.blogspot.com for detailed accounts of such failures:
Please, visit these blog entries at http://beolover.blogspot.com for detailed accounts of such failures:
- http://beolover.blogspot.com/2014/01/beomaster-8000-volume-attenuator-repair.html (here the attenuator needed replacement)
- http://beolover.blogspot.com/2012/12/beomaster-8000-left-channel-volume-cuts.html (here we got away with cleaning contacts)
