A VIEWER sent me this FAULTY B&W Z2 Speaker | Can I FIX It?

This Bowers & Wilkins Z2 speaker was sent over to me by David. It's got a red pulsing LED and doesn't come on at all. It appears to be in some kind of protection mode.

Let's crack this open and see if we can work out what's wrong!

Hope you enjoy!
Steve

PS. I'm not an expert in repairs at all. I do this for fun, and it may not be the best or safest way to go about repairing broken stuff. I'm pretty good at melting plastic though. Please don't copy me - I'm an idiot.

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Some of the magic things I use to break stuff;

Filming equipment;

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[acidhelm]

I think the multimeter was charging the caps, so it saw current flowing and beeped. Once a cap was fully charged, no more current flowed, so it stopped beeping.

[Mymatevince]

Hey Steve, I bought one of these Z2 speakers faulty last year from eBay...annoyingly when it arrived it worked.
If you want to borrow it for testing/swapping chips/wifi boards let me know and I'll post it up to you😎

[davidholt]

Thanks for looking at it Steve. Shame you weren't more successful. Hope you enjoyed the sweets 😁

[KBUIF]

Hi Steve, I mentioned before, when you check capacitors for shorts, you have to allow for capacitors to charge, giving the impression of shorts. You need to allow for caps to charge while you check for continuity. The meter is applying voltage, which will charge caps up to the applied voltage from the meter. Just give it a little more time when you think you find a short.
Thanks.

[pfff]

There's a reset sequence you never did. Hold play/pause and plug in the power, hold for 10s and see if the light changes colour. I'm not saying it'll work, I'm just saying that's what B&W say do.

[shammon]

Honest guy who asks for help to show we are all human and learn wish others great !

[markhearsey]

Steve, Steve… Just got back from the pub, watched half your vid earlier thought I would get back to you fixing this… You gotta follow this one up… You Can Do It…!!!

[Keinapappa]

Whopeee!! Managed to fix my faulty resin UV curing station today. Thank you for inspiring us.

[niftykeentypedog]

*First rule of troubleshooting - measure voltages!*

Around 6 minutes in you measured a medium SMD electrolytic with 3.3VDC on it. That's for all the logic-level chips and I think it comes from the DC-DC converter you checked out.
Confirm this by seeing If the positive pin of that capacitor has continuity with the PH pin of the converter chip (via an inductor.)

There may also be a step-*up* converter to produce a few tens of volts for the power amp stage. Manufacturers would NEVER put a 50V cap where a 25V would do, so stick the old one back in because I suspect that's where this voltage should be. Trace back from the positive pin to find the other DC-DC converter. If it has a shorted output transistor then it's possible the 16V is just passing from input to output via the short.


Doesn't make sense for those caps with different voltage specs to all just have 16V on them.

[michaelgroob]

When you said that IC was a thermal protection circuit, I thought that might be the trouble and since it was heating. I learn so much from all that you do! Thanks for the videos!

[ferarrisman]

i recently bought two of these from ebay one working one with pulsing red light after checking for shorts etc i swopped the wifi boards around to see if that was the issue and i was so if you have a dodgy wifi board you get pulsing red light also wont work without wifi board

[ProfLuisStecca]

Regarding the short circuit, when you invert the test leads, you invert the polarity of the circuit for a fraction of the time.

[jackburton]

I have fixed many electrical items with the throw at wall technique you'd be surprised how many times it's worked for me.

[strike]

Looking on their site, some of their products can take 2 minutes connected to a power source for the capacitors to charge before the device is ready to be connected to an audio source.

[spaideri]

Just a hint. To test a capacitor without removing, just measuring a known voltage usually is a good indicator (power supply's output voltage, 5V, 3V etc.) of a OK cap. Also if you measure the voltage in AC mode, you can sort of get an idea of capacitors capacitance in means that if there is a lot of voltage variance, the cap might have lowered capacitance ie. ability to smooth out the voltage ripple.

[ravenclause]

the explanation you requested: for very small breaks in a conductor, there is a minimum current (albeit very small) for one to detect, so you can encounter small breaks that will conduct, and you can encounter small breaks that do not conduct. that is determined by whether it is beyond a given threshold, similar in respect to "spark gap". This explains well why you think you imagine a short that is not there, because it really can be the case. one way of looking at this is the surface area of the electrical connection in the area of the break determines whether it meets the threshold of the meter for detection. in other words a signal strength is needed slightly more than "0 resistance" for a short to be found by the meter. I spent a lot of time investigating this matter

[pjhb_microsoldering_portugal]

You are charging the big capacitors, if they are flat you will have a short while they are charging...
Love you videos, thanks for them 😉👍

[sishabadab]

Bloody bewildered..
Struggle to put batteries in a walkman..
Great channel, keep up the good work.

[RandomAudioGuys]

UTI260B, Ive watched your channel for over a year and I think this thermal image camera with the Macro lens would help a ton. I noticed when you were looking at the chips the heat map was low resolution. WIth the UTI260B and Macro Lens I can see shorts inside of chips. Its amazing for the money and really good resolution. Its just a good recommended upgrade for your tools.

Keep up the good work bubba.

[Adam-ltfx]

in continuity mode it gives a beep at a fairly high resistance, not sub 1 ohm.. so if you are testing for the short its best to just switch it to resistance mode after and double check..