TerryS wrote: > They swapped two of the pins on the toslink optical jack. The jack has > the red LED that transmits the SPDIF signal through the optical cable as > well as the circuitry that drives the LED. There are three pins on the > part (well actually five, but two are mechanical only): > VCC - Power to the part > VIN - the SPDIF signal (the music coming from the processor chip) > GND - Ground > > They swapped the connections to the VCC and VIN pins so that VIN is > connected to the power supply (3.3V), and the VCC pin is connected to > the SPDIF data out of the iMX6 processor. > The funny thing is that this actually works for some people. It 'sort > of' worked for me. Instead of holding the power to the part on and > controlling the LED on/off times with the SPIF data, it leaves the data > pin high all the time and toggles voltage to the power pin on and off at > the data rate. I don't know the percentages, but it does seem to work > OK this way for some, if not most people. > > If yours doesn't work, there are two ways to fix it: > 1.) The easy way - remove FB7, C310 and R345. These are small parts > near the toslink jack. Then using very fine wire.... I used 'magnet > wire' which does not have an insulation that you strip off like 'normal' > wire. It has an insulating varnish coating that you melt or burn away > with your soldering iron. 32 or 34 gauge or smaller is good. You might > be able to use 30 gauge wire-wrap kynar wire, but that is going to be > tricky. Use the wire to cross the connections to the VCC and VIN pads. > This means wiring from the side of R345 that goes to the processor to > the side of FB7 that goes to the jack. Then from the other side of FB7 > to the side of R345 that goes to the jack. A magnifier of some sort and > a very fine tip soldering iron are needed. > > The 'problem' with the easy approach is that you lose the power supply > filter made up of FB7 and C310. I seriously doubt it will matter. But > if you want to keep the filter, there is a slightly harder way (this is > what I did). > > 2.) The harder way - Remove the toslink jack. This is a real pain > because the ground pin connects directly to the ground plane on both > sides of the board (and maybe internally also). It takes a lot of heat > to loosen that pin. What I did was to use solder wick to clean the > solder from all of the other pins. Wiggle the part so that you can see > that the pins are free to move in their holes. But I was never able to > wick the solder from the ground pin, so after all the other pins were > free, I heated the ground pin with my biggest soldering iron tip and > then pulled the part out. Then I used a tooth pick to clean the solder > out of the hole while heating it. With the jack out of the way, you can > cut the large power trace that goes from FB7 to the jack with a sharp > xacto blade. Cut it right next to FB7, leaving FB7 and C310 connected > together, but not connected to the jack. Use an ohmeter to verify you > got the trace cut. Then scaped some of the solder mask away right next > to the cut on the jack side, so that you can attach a wire there. > Remove R345. Use the fine wire to connect from the side of R345 that > goes to the processor over to the side of the trace cut that still > connects to the jack. Try to keep the wire out of the area where the > jack goes so it can be reinstalled without sitting on the wire. Then > wire from FB7 (the side of it next to the cut) to the side of R345 that > goes to the jack. Re-install the jack. > > Both of these methods eliminates R345, but that is OK. I'm not sure why > it is even there. Probably to 'series terminate' the signal path to > prevent reflections. But it doesn't seem to matter. > I have tested mine in this configuration up to the full 48kHz allowed by > the driver. > > Terry
Great work Terry! Im thinking of removing the toslink transmitter and create a small separate board with both toslink and coax spdif out. This way I have an array of choices for connecting my external DAC to the Community SB. Just one note on your modifications: I would not discard R345. This is needed to limit the drive current to the led of the toslink transmitter. ------------------------------------------------------------------------ Pascal Hibon's Profile: http://forums.slimdevices.com/member.php?userid=7969 View this thread: http://forums.slimdevices.com/showthread.php?t=97881
_______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/discuss
