JoeMuc2009 wrote: > Hi all, > > just wanted to let you know that I had some interesting experiences > recently. It started with a shock when once again I had done SMD > capacitor replacement on multiple SB3s and the dropout rate was extreme. > Five separate devices, all would boot but crash and reboot once they > were commanded to start playback. Three of them "died" somewhere between > the moment I detached the CPU board to do the capacitor replacement and > the moment I put it back together to test. Three! They would do what > every dead SB3 does, show a very dim TOSLINK, no connectivity, no > display. And that despite the fact I hardly ever touched the CPU board > at all. > I still can't explain how it got to this three times in a row (even > five times in a row earlier which had me so depressed I would almost > quit). I wore a grounding wrist strap all the time. I discharged the > capacitors before replugging the CPU board. Used current limiting for > the first startup to ensure that a short won't blow anything up. Used an > IR camera to look for hotspots during powerup. So that was a bit > awkward. The devices were sent to me for repair and shortly after the > repair they would fail and be much worse than they initially were. One > of them had run a firmware update, then restarted and was normal for a > short period of time before it failed. Which brought me to an idea. > Just out of curiosity I extracted the Flash EEPROM from one of them and > put it in my reader. Compared to a known-working SB3 there were a lot of > differences, at least in the first blocks and, expectedly, where the > configuration is held. But I would not assume that the bootloader or > whatever is read first from the Flash is very different between > identical devices. So I attempted to flash the working image to the > EEPROM that was suspected corrupt, with erase first and eventual > verification of course to ensure that it isn't the chip itself that is > at fault. Then soldered the chip back in and, what do you know, two out > of three SB3s were recovered! A Boom PCB is under repair currently, I'll > try the same thing there as the hardware arrangement around the CPU is > similar to that of the SB3. It looks like what I used to call "CPU > death" actually isn't the CPU but the Flash memory for some reason. I > don't know why it happens. It should only be written to during > configuration and during firmware updates, but something during the > repair seems to cause a partial corruption. It's a pity that the EEPROM > needs to be desoldered and put back in place as this can only be done > once or twice before the board gets damaged. But it's way better than > attempting to reflow the CPU which I never succeeded at, and most of the > time it might not even be the component at fault. The EEPROM is not easy > to handle thanks to its 0.5mm (or so) pin pitch but way easier than the > BGA stuff under the CPU. > I have too little experience yet to document this or proclaim it as one > of the first measures to fix, and due to the complexity of the operation > it should rather be considered a last stand, but still. There is a lot > of new hope for the stack of failed SB3s and Booms I have around, and > I'll let you know how I fare with it. > > Cheers, > Joe
That's excellent news! I wrongly thought that you already compared flash content in the past. I don't have my programmer here but I'll try as soon as I can get it LMS 8.2 on Odroid-C4 - *SqueezeAMP!*, 5xRadio, 5xBoom, 2xDuet, 1xTouch, 1xSB3. Sonos PLAY:3, PLAY:5, Marantz NR1603, Foobar2000, ShairPortW, 2xChromecast Audio, Chromecast v1 and v2, Squeezelite on Pi, Yamaha WX-010, AppleTV 4, Airport Express, GGMM E5, RivaArena 1 & 3 ------------------------------------------------------------------------ philippe_44's Profile: http://forums.slimdevices.com/member.php?userid=17261 View this thread: http://forums.slimdevices.com/showthread.php?t=117140 _______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/discuss
