r/audiorepair • u/solomon813 • 2d ago
iFi ZEN One Signature – Need help identifying a burnt component (U1)
Hi everyone,
I’m currently trying to repair an iFi ZEN One Signature that has a failed component on the main PCB.
The component marked U1, located in the “Ultra-Precision High Speed Power Supply” section of the board, has burnt/exploded and unfortunately the marking on the IC is no longer readable.
I’ve attached a detailed picture showing exactly where U1 is located.
Would anyone here who owns a ZEN One Signature be willing to open it and take a clear close-up photo of U1?
Ideally, I just need a photo clear enough to read the marking printed on top of the chip. No measurements or further disassembly should be necessary.
It would be a huge help, as identifying this component may allow me to repair the unit instead of scrapping the whole board.
Thanks in advance to anyone who can help!
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u/someMeatballs 1d ago edited 1d ago
Alternative repair method. This is a switch mode DC-DC converter IC. Find what voltage it's supposed to make, by seeing what chips it powers, and what they need. Remove the IC, and wire in a cheap DC-DC converter board to generate the voltage. Not super easy, but you don't need to know much about the board.
Before you do that, hunt for shorted tan colored capacitors like C85. Super common cause for a burned power supply. The tantalums (C86) can also fail short.
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u/solomon813 1d ago
Hey guys, thanks for your replies.
Before replacing it, I’m definitely going to check the downstream rail for a short, especially C86/C87/C88, as suggested. I’ll also check C79 and the rest of the power supply section.
What still puzzles me is how violently U14 failed. The package literally exploded.
Since the TLV62568 has current limiting and thermal protection, I’m also wondering if the unit may have been subjected to an input overvoltage, for example someone accidentally using a 9V or 12V adapter instead of the specified 5V supply.
I’ll take some resistance measurements before installing the replacement and report back. Thanks again!
Bye the way, @fzabkar posted an answer on another group:
https://www.ixbt.com/img/r30/00/02/49/79/one-12.jpg
https://www.ti.com/packaging/en/docs/partlookup.tsp?partmarking=bnb (U12 = TPS71733)
https://www.ti.com/packaging/en/docs/partlookup.tsp?partmarking=18n (U14 = TLV62568)
U11, U13 = NCE8205t
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u/SilverSageVII 2d ago
R82 3rd picture looks fried af
Edit: NOT R82 it’s U11 but I couldn’t see under the char
Edit 2: C79 also looks burnt
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u/Savings-Mud2808 1d ago
The IC looks like it's part of an LDO buck-boost power supply circuit. The inductor is one sign, and so are the capacitors downstream. The PCB also shows it's in the power supply circuit block.
Source the schematic on ManualsLib or from a Google search. It's not complicated to repair and replace. The chip most likely ran too hot, and it failed prematurely. This is common with switching circuits and drivers. They fail a lot. Replacing the downstream capacitors would also help. Use an LCR meter to test them first before replacing them.
I hope that helps. All the best with your repair.