Sonos Play 5 (Gen 2) dismantle and repair

[jamhall1]

I don’t generally write on forums, but this information seems to be missing from the internet, and I was hoping to help others finding themselves in my situation.

My Sonos Play 5 (Gen 2) suddenly stopped playing one day.

After a bit of playing around I figured out it was the wireless that had died in the unit (ethernet interface was still working fine and the speaker worked when hard wired).

Some searching later I found that this is a common fault on this unit (several forum threads about it).

It seems that Sonos are offering to replace the damaged units outside of warranty, however upon contacting them it seems that they were only prepared to provide a refurb unit in exchange. Not acceptable to me as I know I’ve not thrashed my unit, and it’s totally pristine.

Unfortunately though I couldn’t find any information on the internet about how to open these units up (not a single teardown to be found for the Gen 2).

After a bit if deliberation I decided to give it a go thinking that there was a discrete wireless card in there that could be replaced (I saw mention of other Sonos units being architected this way).


I managed to get it open with some very careful wrangling. The photos should give a pretty good idea for anyone that finds themselves in a similar situation.

I was then a bit annoyed to find only a single digital board with integrated 3 branch wifi (with 6 antenna elements). I was going to have to do some proper diagnostics :-(

Thankfully after not too long I found a pretty low resistance across one of the two obvious main voltage regs on the digital board. The rail seems to go to some transceivers in the wifi signal paths (I’m not really familiar with 802.11 architectures though).

Not being totally sure what I was seeing, I soldered some wires to the board so I could power it from a bench supply and get the scope in there. The buck converter (TPS54335A) was trying to switch in chirps but giving up. Now fairly convinced something was up here.

Eventually managed to see a marginally lower resistance across the buck converter package itself compared to the output cap, so this was now prime suspect. Some forum searching yielded this result:


https://e2e.ti.com/support/power-management/f/196/t/810605


https://e2e.ti.com/support/power-management/f/196/p/745780/2763699


https://e2e.ti.com/support/power-management/f/196/t/891078


Smoking gun!!! Now had to liberally Kapton the surrounding components, remove a capacitor out of the way and get the IC off while a couple of new ones were ordered from Mouser.

I’ve done a bit of prototype assembly and rework in the past, but I’m mostly a Firmware engineer, so always a bit nervous of cooking a board before I get the part off! Especially something like this powerpad package.

All went well though, and after the new part was on I discovered that the mystery rail was 5V, and all worked like a charm again.

Once again, I hope this helps someone else desperately trawling the internet for how to get into one of these things!

[jamhall1]

More pics

[timvandenboo]

Thank you very much for your share in information about this.

I got actually 2 Sonos Play 5 Gen 2 here with this problem.
Only my problem is slightly different and maybe someone has an idea.

After disassembly of the sonos and do some quick research on the buck converter you mention. I found a short on the PH line. So I cut the line and the short on PH was gone. Turned out the buck was internally shorted.

To ordered some new bucks and soldered this one on. (did a short check again)

And with full confident, plug the cable into the wall socket. pffffffss short and smoke on the PH line again.... weird.

So remove the "new" buck and measured again. Now there is a permanent short on the PH line.

Connected this PH line on my bench power supply and could locate the short to this location on the RF line. (antenna signal line) Where an internal short of this component.

Does anyone has a suggestion on what to do next? Replace the component circled in red?

[explorer232]

Hi,
my sonos not power on anymore. Probably faulty power supply. What is the correct output voltage from power supply please? In my case there is not stable voltage from 13.7 to 14.1V. 


Will logic board start correcly when I connect only additional 20V power supply to input? (Without connected power supply pcb) 

[jamhall1]

Hi I realised I did not write down the rail voltage coming across to the logic board, but pretty sure it’s 12v, and those 2 regulators are 5v for WiFi and 3v3 for processor.
The absent capacitor pads where I soldered temporary wires to is where the incoming 12v should be able to be measured.

[explorer232]

Hi,

thanks for info but are you sure ? Measurement on the missing caps points is output voltage from power supply.
In the psu is NCP 1937 controller with standard output 20V by datasheets.

And all used caps has voltage rating 35V.

[jamhall1]

I’m not sure, it’s quite a few beers ago and I didn’t take photos or notes of other things I wasn’t immediately concerned with. It could very well have been 20V. Unfortunately I’m not too tempted to open it up again just yet!

If you have a doubt, why not try to power your logic board from 12v and see if the 5v, 3v3, and then Ethernet and WiFi come up? You are seeing a lot of ripple on that incoming supply otherwise?

[explorer232]

Hi,
with external power supply 12V connected to logic board I see that all power rails are OK (5v ,3.3v, 1,4v) but its dead. No wifi, no lan, no led.

One question before I'll throw it away. Is logic board working (lan, wifi) without connected original power supply and button/led notification board?

If no maybe my notification board is faulty.

[jamhall1]

Hmm looking back at my pics, I think I must have only been measuring voltages while the logic board was on the bench being powered externally. Once I’d got the WiFi 5v rail working I must have put it back in the unit to test it actually worked.

Who knows if there’s some power good or something on that flex cable that allows the processor out of reset.
You could probe around the digital stuff with your scope to see if anything is going on.
I realised I didn’t even take a photo of the cpu side of the board! I think it was a Freescale part? You might be able to tell if it’s been released from reset or if it’s reading from flash after power up.

[explorer232]

Hi,
logic board is dead. By my research logic board work with 12V external power so no original psu is needed for debugging. Original power supply output is 14.17V.
I would like to bought logic board for this sonos play 5 gen.2 There can be some problem, but I need booting one.

Thanks for offers.

[ch.scherpf]

Hi Guys, i´m new here in the Forum. Coming from Germany with the same issu on Sonos 5 gen2. No Wifi.
I changed the Buck-Converter as shown in the first post but there is another issu with my logic board.
The Buck is switching on and off all the time, every half second or so. I can see a voltage 1,2... then 0; 0,5... then 0.
Does anyone of you have a idea where to look at next?

When i plug the complete box to the socket it switches on for about 30-60 seconds and then the led dies.

Best regards
Christoph

[jamhall1]

Hi Christoph,
I guess the unit didn’t previously die after 60 seconds, and worked fine on Ethernet?
If so then I’d guess either you may have a soldering issue with your repair, or that rail going to the wifi is way overloaded by some other problem.
Have you checked the switching of the buck on a scope?
Is the main incoming supply feeding both buck converters good?

James

[ch.scherpf]

Hi James, sorry for my late response. I sold the box as not working so there was no need to do further serching. But thanks for your help!

[ouimetnick]

Did the wifi even work slightly? I have one, I've reset it, and it my iPhone/Sonos app sees it, but when the phone tried to connect to it to then add it to my wifi network, it gives me an error.

Going to call Sonos to see if they would replace it before I proceed. The refurbished units look and function brand new anyways.

[jamhall1]

My phone could ‘see’ it but then could never see the ad-hoc network that it creates when pairing. I’d forgotten about that. Is it likely to have some form of Bluetooth to initiate the pairing?

[ouimetnick]

Just checked, and damn, there's a looooong lead time on TPS54335A ICs.

[jamhall1]

Yes, TI regulator ICs are rocking horse poo these days! We’ve had to redesign a load of them out at work. You could bodge in a discrete regulator module until the world is back to normal perhaps