Beomaster 8000 Repair: Tuner Issues
Beomaster 8000: A dead U264B prescaler in the tuning frequency feedback needed replacement
The Beomaster 8000 features digital control of the tuning process. The frequency is adjusted via a feedback mechanism where the tuned frequency is fed back into one of the microcoontrollers via a prescaler, which amplifies the tuning oscillator signal, while also dividing the frequency to something closer to the clock frequency (1 MHz) of the microcontroller. If the tuner seems to behave erratically and ignoring the set frequency, chances are that the feedback loop is interrupted.
Please, visit these blog entries at http://beolover.blogspot.com for some detailed accounts of such failures:
Please, visit these blog entries at http://beolover.blogspot.com for some detailed accounts of such failures:
- http://beolover.blogspot.com/2013/09/beomaster-frequency-counter-feedback.html (lots of detail about the feedback mechanism)
- http://beolover.blogspot.com/2013/10/beomaster-8000-tuner-repair-exchange-of.html (replacement of the U264B prescaler chip)
- http://beolover.blogspot.com/2014/03/beomaster-8000-no-tuning-above-93-mhz.html (blog entry about a dead flip flop chip, related to a beoworld thread that can be found here)
