Sonos Playbar No Power (again) after successful repair

[rotorrocket]

My Sonos Playbar wouldn't power on, a typical power board issue.

I tested the rectifier and the MOSFET with a multimeter. I had to desoldered the MOSFET to ensure I got an accurate reading and it tested good. Used fresh thermal paste for the heatsink and resoldered it to the board. The rectifier tested good on board and wasn't removed.

I replaced the two 400v 100uF capacitors that looked suspect and know to fail. The ESR meter table doesn't have a 400v capacitor listed so I just replaced both with the same. The smaller capacitors tested good with an ESR meter on board.

Nothing else looked suspect on the power board.

Screwed the whole unit back together (whew) and it came back to life!

I used the Playbar for about 45 minutes at a normal level without any issues and shut it down as I was done listening to it. I unplugged the unit.

The next day I plug the unit back in and it's dead again. No power.

It wasn't plugged into the same outlet when it first failed. So it's not an outlet issue.

Totally perplexed.

Any assistance would be greatly appreciated.

[R_J]

Re: Sonos Playbar No Power (again) after successful repair

Try replacing the startup cap for the smps ic.

[rotorrocket]

Re: Sonos Playbar No Power (again) after successful repair

Thanks for the reply.
Here's a picture of the board.

[rotorrocket]

Re: Sonos Playbar No Power (again) after successful repair

The small cap between the rectifier and the heatsink?

[R_J]

Re: Sonos Playbar No Power (again) after successful repair

This should be the one, it should be off the vcc pin of the ic, Post the number that is on the ic, it's datasheet may have a sample schematic.

[rotorrocket]

Re: Sonos Playbar No Power (again) after successful repair

This should be the one, it should be off the vcc pin of the ic, Post the number that is on the ic, it's datasheet may have a sample schematic.

Here's a picture.
Looks like TE5AA

Thanks!

[R_J]

Re: Sonos Playbar No Power (again) after successful repair

It is a FAN6300H, the cap. should be off pin6

[rotorrocket]

Re: Sonos Playbar No Power (again) after successful repair

Couple more pictures of the suspect cap.

[rotorrocket]

Re: Sonos Playbar No Power (again) after successful repair

And another.

Helpful?

[R_J]

Re: Sonos Playbar No Power (again) after successful repair

And another.

Helpful?

There is no way to tell if the cap is dried out and has lost capacity from a picture, these caps rarely bulge or leak. but if the capacity is low it will not charge to start the ic and keep it running, You could check the voltage on pin 6 (please don't short the pins). This is on the hot side so you need to use hot ground for the negative of your meter (pin4 is connected to hot ground)
The voltage needs to be above 16v to start. usually runs about 20~25v, if pin6 drops below 10v the ic turns off

[rotorrocket]

Re: Sonos Playbar No Power (again) after successful repair

Thanks. Would you happen to know the cap specs? Unfortunately my only pics don't capture it.
It's all put back together at the moment and would like to get a replacement ordered right away so I have it ready if it's indeed the culprit.

[R_J]

Re: Sonos Playbar No Power (again) after successful repair

Your pictures do not show the value, I suspect it is between 10~47µf and around 50v, Any good quality 105 degree cap would be ok. This may not be the problem, since the fault is intermittent it could be a poor solder connection on one of the components.

[duder]

This may help others. I had a similar problem. I had replaced the fet, controller i.c., a 100 ohm resistor and the startup capacitor. The power supply would not start. Then I noticed the diode (bat54c) and 100 ohm resistor at the gate were blown. Also the 4 resistors (0.15 ohm) at the source of the fet were blown. I replaced those and everything is good.