Skunk;186232 Wrote: > > What would be helpful to me is if you/someone could define the > theoretical connection points in the following pic, especially in terms > of how Vcc,Vdd are powered together/separately (don't they need to see > their voltages in sequence- i.e. from a rail?). > Well it has been a long time since I poked around inside my SB3 but the way you figure these things out is to check the chip datasheets and then visually trace the wiring on the circuit board. Using a multimeter to verify things are wired up the way one expects is critical. You do this by measuring resistance with the SB3 turned off.
Looking at the DAC datasheet you learn that Vcc (5v) is pin 6 on the PCM1748 and Vdd (3.3v)is pin 5. From your photograph, you can see that the power supply caps for Vcc are C11 and C16 and the power supply caps for Vdd are C10 and C6. You now need to trace back from those caps and figure out which regulators are supplying Vcc and Vdd. Then you have a few options in terms of how to wire in new Vdd and Vcc supplies. Easiest is to just remove the existing regulators and use the pads for those regulators as the entry points for the new power supplies. Hope this makes sense. ---Gary -- GaryB ------------------------------------------------------------------------ GaryB's Profile: http://forums.slimdevices.com/member.php?userid=3169 View this thread: http://forums.slimdevices.com/showthread.php?t=19822 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
