Nice find!

When the circuit did not come on… Was there any error in the app or light on the Play:5?

No errors or light. Everything looked normal. Just no sound and very faint at max volume.

It’s really good to see people posting about actually fixing faulty Sonos kit, rather than simply ‘recycling’ it.

For the sake of a few (probably quite cheap) components and some skill, the planet’s just a tiny bit better off ;-)

Excellent repair there!, a 2 pence resistor saving a very expensive speaker.

Great share Pietje. Will try to replace the resistor this weekend.

Jywl12, before you replace, check the value with a multimeter. No need to replace a working part...as I indicated, the mosfet is another target as well as a few other parts controlling the gate signal.

Here are my readings

R27835 - 10k ohm

R27834 - 4.99k ohm

R27827 - 5.00k ohm

R27828 - 20.08M ohm

R27833 - 198.7k ohm
 

looks like R27828 is the one.

Here are my readings

R27835 - 10k ohm

R27834 - 4.99k ohm

R27827 - 5.00k ohm

R27828 - 20.08M ohm

R27833 - 198.7k ohm
 

looks like R27828 is the one.

 

Yes for sure, R27828 should be like R27834 and R27827, from the foto they seem to have the same code (68b - 4.99kΩ ± 1%). This resistor is also in the path from the CPU board to the gate of the mosfet. I bet replacing it will fix your problem. Please let us know!

My store doesn’t sell 68b, so I used the normal resistor as well. 
 

Finally my play 5 bounced back to life!!!!
Really thanks to you, Pietje in pointing out where to troubleshoot. Cheers!!!

My store doesn’t sell 68b, so I used the normal resistor as well. 
 

Finally my play 5 bounced back to life!!!!
Really thanks to you, Pietje in pointing out where to troubleshoot. Cheers!!!

Thanks for sharing Jywl12. As amun said, 

"the planet’s just a tiny bit better off"...hopefully this post can rescue a few more. And whoever at Sonos reads this, think about recycling this way instead of the entire device!

Hi, I do have a new problem now after fixing the Play5. The woofer driver runs hot, too hot to even touch it. It didn’t shutdown though, but I am worried too much current flowing thru the woofer. 

My experience is that the amplifier stages do get very hot. Quite a few Play 5's which I've seen have a brownish PCB colour around mosfets. Did you check the woofer resistance? 

Thks for sharing. The source of the heat is not from the PCB. That was my prime suspect too. After powering up and played some music, the woofer magnet heated up, along with its metal parts. Will check the woofer resistant. Is it 8ohm?

I found the issue. Some of the components exploded. Q27507/Q27502/Q27509/Q27503. Any idea what are the markings?

@Pietje Puk 

I checked every single 10k Ohm and 5k Ohm resistor yesterday and didn’t find any issues. I could have missed one, but I swear I checked the whole board.

Would you mind offering more detail on the next areas to check? I know you mentioned that a mosfet could be to blame, but is there any mosfet it’s more likely to be than another?

Outside of mosfets, what else should I be looking for?

@soobrex1 

Check mosfet Q27621. This is the mosfet that switches the 24V to the amp stage. Best to test with the unit powered up. You should be able to measure the gate voltage when you hit "play" on the App. Next you should find 24V on the amp stage main power line.

Good luck!

@Pietje Puk

I’ve separated the main board from everything else - can I power up the board on its own? I’m guessing not, since the play button is connected to the smaller control board.

Here’s where I’m at:

@soobrex1 

In red the section which drives the mosfet (in blue) gate signal from the control board. In addition to the resistors there are also a few transistors you can check. You should be able to access these components with a multimeter with the entire unit cabled and powered up.

By the way, you never mentioned what your problem is. Can you hear a faint sound at max volume?

@Pietje Puk 

Correct, I have very faint sound at max volume through line-in or S1 app. When I plug headphones into it, sound is normal volume.

The problem I’m having is that I’m not particularly familiar with testing electronics. I can follow directions, but can’t really figure it out on my own, so looking for help on not just what to test, but how. I did watch a YouTube video on how to test a mosfet, but it was desoldered from the PCB for the test.

Besides the red section that you’ve outlined, are there other sections of the PCB you feel like could also contribute to this problem?

BTW thanks for this thread and your help thus far.

@soobrex1 

That makes things much harder. I suggest you put it all back together and leave the speakers out but connected. 

Assuming you have a multimeter you need to measure each pin on the mosfet, black lead of the multimeter to gnd and measure with red lead measure each of the pins with setting VDC on your multimeter. Measure with music playing from the S1 App. Post the readings on a picture on this forum

Great information and guide.

I had the exact same symptoms and after following the advice here……exact same faulty resistor.

All working now. Thank you.

Thanks for all the info. My Play 5 has been the same as the above for the last year or so. I don’t have enough expirence to troubleshoot my self but with the info here I started testing and found that all resistors mentioned were within spec apart from R27828 which gives OL so I will repalce it tomorrow.

Earlier it was doing the same thing, playing music but very very low even on full volume. Now, strangly, it has just started working which it would do intermittently before. 

With it working I measure 25v on the MOSFET at all 8 pins when playing music so not sure quite what is going on here?

Also, is it normal for a slight hissing sound to be heard from these units while powered up?

The hiss isn't normal.

On the MOSFETs...that's not right either.  The device may have failed.  With no power applied, give it time for the capacitors to all discharge, and then check for continuity between the pins.  If they are all shorted together then it's bad.  If not, you can use the diode test function and should see either infinite or a small voltage drop between the gate drain and source pins (check all six combinations).

This isn't guaranteed to work as a test of a MOSFET in circuit, but it will usually be enough to find a problem if there is one.

Thanks Tim, will give that a go. The odd thing is that it’s been sat here on my desk working for the last few hours but this is what it did before and it just got so bad that it only worked occasionaly.

Repalced the resistor and still working. Still get 25v on all pins of that MOSFET though 

Will just have to see how it goes now. Was intermittent before so wont know for a few days / week if this has worked.