All,

Have a Seagate 1TB laptop that is not spinning, board number is 100570750 REV A. Was thinking the TVS has blown, but am not 100% sure that it is or not. Cannot read the blown chip too well, but it looks like it says:
QA
R003

Can anyone advise based on the attached pictures what they think? Ideally if it is the TVS we're hoping to just snip it and image the drive in DDI.

Thanks,
Dizi

Given that it has clearly got very hot, then IMHO it's likely to have suffered catastrophic damage. Did you measure the resistance across it (both directions) with power off?


Yes, that's a 5V TVS marking. It also seems to be connected across the 5V SATA power input (as expected for a 5V TVS), but you'll be able to confirm that more clearly with the PCB in front of you, than I can from the photo.

Of course there is no guarantee that its sacrifice has prevented any damage to other components... It would be interesting to know what led up to this - what did the customer say?

The customer reported that is just stopped working. But we work through a 3rd party on this one, so it's like the telephone game by the time we get things in.

Besides the fact that it looks like a TVS, what other signs do you notice? Looked for the >l sign, but didn't see it nearby.

Dizi

That's a shame, but thanks for explaining. I always find the background interesting when I'm repairing PCBs (although in my case, they aren't from disks), as sometimes a pattern is seen (in either the cause of the damage, or the damage itself). Anyway...


I don't understand the question - signs of what? Are you asking why I'm saying that's a TVS? Or are you asking about its polarity on the board? Or ...? Can you clarify the question please

Sorry for the confusion - why you're saying it's a TVS.

Always easy to test: check for short on the appropriate voltage line, if present remove the TVS, check to verify that short is gone. If you remove it nicely instead of cutting, you can put it back if you need to.

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@Dizidago357,


Its marking, its size, its location & its electrical connections i.e. where its PCB pads go (assuming, as I said you should check, that it is connected across the 5V power input - a photo is never as good as having it in your hands, as you do, although I'm 99.999% sure of its connections anyway).

As drc said, and as I mentioned in my first reply, a resistance check will confirm it's health, or likely, the lack thereof

See http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html

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