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Blown power supply for home Music Streaming device (Zeppelin Air) - Pictures inside

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dmul

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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...





 

betwixt

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Repairable - certainly. Finding its value - difficult without a schematic or another PSU for comparison.

From what I can see, it is wired in the primary (high voltage) side of the isolating transformer. It is therefore likely that one or more of the three power transistors lined up between the transformer and reservoir capacitors (bottom of first photo) is also dead. It would be a good idea to check them all.

Can you carefully clean the 'blast marks' away from its part number and tell us what it says. The outline and position on the board suggest it might be a fuse, it doesnt look like a capacitor or semiconductor, the letter before the '1' will give a clue.

Brian.
 

dmul

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Repairable - certainly. Finding its value - difficult without a schematic or another PSU for comparison.

From what I can see, it is wired in the primary (high voltage) side of the isolating transformer. It is therefore likely that one or more of the three power transistors lined up between the transformer and reservoir capacitors (bottom of first photo) is also dead. It would be a good idea to check them all.

Can you carefully clean the 'blast marks' away from its part number and tell us what it says. The outline and position on the board suggest it might be a fuse, it doesnt look like a capacitor or semiconductor, the letter before the '1' will give a clue.

Brian.
Thank you Brian. I'll certainly try and get the schematic from Bowers & Wilkins. Would it be possible to test the capacitors in situ from their secondary side solder points? (I have a couple of multimeters but they are pretty generic shed ones)

Will attempt to clean the blast site for clues on the component... initially though it looks like nothing is imprinted on it....
 

betwixt

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You can't test capacitors with most multimeters, even if they are out of circuit. In a power supply you not only need to check their value and leakage but ESR as well which requires a more specialized tester.

However, that doesn't look like a capacitor to me, it's thickness, width and length suggest it is more likely to be a resistor or a fuse. The clue would be in the white silk-screen printed legend on the board beside it. It looks like two characters and the second is a number 1 but the first letter is obscured by the blast mark (below it in the last picture). I doubt you would be able to see any marking on the component itself but the board marking could tell us what type of component it was.

Brian.

[late news] I found a picture of an undamaged board on a well known aution site. From the picture I can see the print says "R31" so it's a resistor and the value is "R50" meaning 0.5 Ohms. Check the transistors then replace the resistor and try it out. They cost about 1p each !
 
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dmul

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Hi, yes indeed its R31.. i cleaned the damaged area as much as possible.



Would you have the auction site link to hand? I checked the most popular one and could see no Zeppelin power boards on there.

I'd imagine also that the surface mount resistor, despite its cheapness wont be available in my local maplins! :)
 

betwixt

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It was at:

http://www.ebay.co.uk/itm/Zeppelin-...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

but the auction has ended, the photographs are still there though, near the end of the listing.

Maplin don't sell them, Rapid don't sell them but Farnell have a page full of them:

http://uk.farnell.com/webapp/wcs/st...&aa=true&pf=110030112,110056631,110071516&vw=

It should win an award for the biggest web link ever! Measure the length and width of the old resistor to find an exact match or it won't fit on the pads.

Brian.
 

Relayer

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Hello Dmul,
Please check the modified pictures below on what I would recommend that you check.
If you're good at using a soldering iron, then may I suggest that you can obtain two 1 ohm 0.25 Watt resistors, twist the leads together and wire them in parallel. Lightly tack them in place of the original burned out resistor. But make sure you've checked the components I've suggested and cleaned up the area of a damaged resistor. This will save you the purchase of a new resistor if there still is a fault that may not be able to be repaired or you're going to need other components when you've fitted the proper type resistor.

Board Underside A.jpgBoard Underside B.jpg

I hope the above helps.
Please let us know how you get on. Good Luck!!!
Regards,
Relayer
 

iso14000

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Hi all

I'm already on another french board, and I have also fix several Zeppelin's power. If it can helo I give you the like to the thread where I post some schematics "reversed"
The main problem come from the main's voltage detection circuit : It automatically commute a triac to manage 110V/230V country voltage.... but from time to time for unwanted reason it locks on 230V country.... and unfortunatly the voltage on capacitor can raise up to 800V because of the charge pump

https://www.abcelectronique.com/forum/showthread.php?t=92915

bye
 

iso14000

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btw

to fix this SMPS : change FAN7387 H driver, both MOSFET, remove TRIAC, change 2010 0R5 resistor and the small bipolar transistor (npn T9) next to it, the fuse....
from time to time C9 is damaged : 1nF 500V

regards
 

cipriman

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Hi ,i have a problem with Zeppelin air power supply.The both mosfets was in shortcircuit,R31,R34 and T9 defective.I replace mosfets,R31,R34,T9(with bc817 npn transistor) ,FAN7387,and the fuse,i remove the triac from the board(i use it at 220v) .the power stars,but the chooper trafo have a verry loud noise (high pitch noise,like is in short or oscillating),the mosfets became hot very quickly ,and at high volume intrerrupts soud and distors.I check C7 and C8,i replace C5 and C31,and i change all the capacitors in secondary..but the same.Any sugestion?
 

cipriman

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I manage to repair it,was R24 (170k instead of 3,3k),work`s fine now.A simple way to test the power supply,to start amplifier power supply just put START pin to +5v.
 

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Remigijus01

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I manage to repair it,was R24 (170k instead of 3,3k),work`s fine now.A simple way to test the power supply,to start amplifier power supply just put START pin to +5v.
Dear Cipriman,
In order to start PSU for testing purposes, do you mean that START pin should be connected to +5v pin?
What should happen then? Should relays click by switching? Thanks
 

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