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I have a Sonos Play:3, which is past its warranty. I dismantled it to find it has the well documented fault with a blown capacitor. However, there is also damage also to one of the surface mount diodes. I have sourced some new capacitors to replace those, however I am not sure what spec this diode is, and wondered whether any of you have had the same issue and if any solution was found? It appears to be D307, and has a code of AN 97 printed on it. As far as I can see, I will have to bridge the track to wherever the diode's anode was connected.

Any advice would be greatly appreciated, as I cannot find a schematic or circuit diagram anywhere, and the board is quite badly charred!!
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enter image description here

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  • \$\begingroup\$ The diode can probably be replaced with an inexpensive Si diode with leads such as a 1N4007. However, the charred PCB indicates other issues, such as burned out inter-layer traces. Replacing those two components is a quick fix -- but don't be too concerned if it still does not work. \$\endgroup\$ – DrMoishe Pippik Oct 25 '18 at 20:11
  • \$\begingroup\$ That wasn't just a charring, that was a full-blown fire! From the pics, looks like it went to the cap. So cap failed (shorted!), burned up trace and diode. Is it a multi-layer PCB? You'll want to get that carbonized fiberglass out of there - charred PCB is conductive. I'd use a Dremel or similar rotary tool. It would be helpful to get another one to see what the board is supposed to look like (and test against if rebuilding several traces.) \$\endgroup\$ – rdtsc Oct 25 '18 at 20:59
  • \$\begingroup\$ Thank you both for your reply. I will look into the Si diode, and leads. I guess the issue then is working out where the tracks from the left hand side of the damaged diode went. I'll upload another photo of an intact board. \$\endgroup\$ – user202396 Oct 26 '18 at 22:18
  • \$\begingroup\$ I have uploaded another image of a working board (and diode) close up \$\endgroup\$ – user202396 Oct 26 '18 at 22:27
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There's a few online references for component markings. This one has the "L6" marking for a number of possible components, the most likely, since it looks like a SOD123 case, is BAT46W

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  • \$\begingroup\$ It's hard to make out even in that photograph but to me the case looks more like an SOD123FL (flat lead as opposed to gull wing style). This may help narrow down the manufacturer/type. I only mention this because SMD ID marks tend not to have much of a standard (eg MMBT3906 from Diodes Inc basic mark is K3N, from NXP is is 7B). You may find that the other diode parts give you a clue (depending on economics, they may source from same manufacturer). \$\endgroup\$ – isdi Oct 26 '18 at 0:03
  • \$\begingroup\$ BTW, I can't tell, but is that a small chevron after the "6"? usually lower case/oddball characters indicate point of manufacture, also a help (even if it's specific to a manufacturer, because that symbol will be used on other parts). \$\endgroup\$ – isdi Oct 26 '18 at 0:17
  • \$\begingroup\$ Thank you both for your reply. I will have a look at the above. DrMoishe Pippik has suggested above that I could just use a 1N4007 with leads to replace the blown diode. What do you think to that idea? Also, as I said above, the next issue would be tracing the tracks under the charring to re-establish connections that have been broken. \$\endgroup\$ – user202396 Oct 26 '18 at 22:20
  • \$\begingroup\$ I have uploaded another image of a working board (and diode) close up \$\endgroup\$ – user202396 Oct 26 '18 at 22:27

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