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Power Supply dead? - Pictures inside.

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dmul

New Member
Hi all. Hopefully someone here can help advise me on this issue.

I have an iPod/music player called a Bowers & Wilkins 'Zeppelin air' that stopped working a while ago. Zero power to the unit despite fuses and external supply being good.

The power supply board in the unit is known to be the fault with these devices. So I removed the board to see if I could find any blown capacitors.

I found none, all looked in good order so I flipped the board and saw what looks like a burned out IC chip?

Is this board dead or fixable at all?

The manufacturing company wont sell a new power board, they want the unit in (at cost) to repair. I would just like to put my mind at ease that there is nothing I can do before sending it back.


Pictures below, thank you for looking :)
Dave

Top side of power supply board, all looks OK.



Bottom side... and close ups of the chip I spotted...





 

Les Jones

Well-Known Member
Most Helpful Member
This is a switch mode power supply. When components fail particularly on the primary side they tend to cause a number of other components to fail. This makes them quite difficult to repair. Unless you have a good understanding of how switch mode power supplies work and are experienced on working with high voltages then I suggest that you do not try to repaire this yourself. It looks like you may be able to get a schematic from the manufacturers. This is a link to their website.) If you enter the model number of your device you may find the schematic which will save the time needed to trace it out from the board. Without the schematic you cannot work out what the component that you can see that has failed may have also caused to fail. Or what component may have failed and caused this component to fail. If you can post the schematic or a link to it it is just possible that one of the forum members may be able to work out the possible cause and effects of the failure. If you have to trace out the schematic yourself just the primary side will do to start with.

Les.
 

tomizett

Active Member
I agree with Les; it may well be repairable - but don't underestimate how much of a challenge (and how dangerous!) it might be if you've not got a great deal of experience with these things.

Can you see what the white marking is at the end of the failed component? It's obscured by soot...
 

JLNY

Active Member
That burnt-out component looks to be either a large chip resistor or capacitor rather than an IC. given that it is connected to one of the primary-side power transistors, my guess would be that it is a power resistor of some kind. cleaning off some of the crud on the surface and on the board below it may allow you to read its value and its designation on the PCB mask. You might attempt replacing it, but it is entirely likely that a fault somewhere else on the board caused it to fail, and so it could fail again in short order.

If the manufacturer is offering to repair it at a reasonable cost, I might take them up on it.
 
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