Question re: old Seagate Momentus PCB.

[Lord Kamina]

Hello everybody; I'm new here and I've got a rather tangential question that I was hoping somebody might help me with.

I've got an utterly trashed old Barracuda 7200 1TB... there's two really nice rings engraves on the platters.

BUT, the PCB is (or should be) fine. As things would have it, I'm hunting for components to fix an old Dell Inspiron and currently I'm missing a couple capacitors. I know the specs of what I need but have been utterly unable to get them. Ordered a couple from AliExpress but I doubt I'll get them before a month or two.

As some might foresee where this is going... I was wondering if I could turn this PCB into a donor for the laptop I'm trying to pull back from the dead. Problem is, I don't have a capacitance meter (or the money to get one), since that would obviously be too easy...

Does anybody have the schematics, or has anybody ever actually tried to find the values of the capacitors on this board (100536501 REV A, V60131 controller)?

Hopefully somebody is as insane as I and will be able to help. Cheers!

[HaQue]

So you want to replace the Caps on the mainboard (that are bulging or leaking) with caps from The Hard Disk?

better off finding some from an unwanted mobo. you say you are missing the caps, do you know the type and value.. were they plastic can electrolytic or metal? value/voltage? do the ones on the HDD have any markings to decode?

if you need say 10uf/10v you can safely use 10uf/16v or 10uf/25v that are more common

There are better places to buy things than ali express, surprised if ebay didn't have them

[fzabkar]

... I'm hunting for components to fix an old Dell Inspiron and currently I'm missing a couple capacitors. I know the specs of what I need ...

Can you tell us?

[Lord Kamina]

So you want to replace the Caps on the mainboard (that are bulging or leaking) with caps from The Hard Disk?

better off finding some from an unwanted mobo. you say you are missing the caps, do you know the type and value.. were they plastic can electrolytic or metal? value/voltage? do the ones on the HDD have any markings to decode?

if you need say 10uf/10v you can safely use 10uf/16v or 10uf/25v that are more common

There are better places to buy things than ali express, surprised if ebay didn't have them

They're SMD, actually. And sadly (I noticed after posting this) the PCB doesn't have much in the way of markings. It has some rough "sections" numbered, although for each there appears to be one, two types of caps at most. I know SMD are (very) vaguely color-coded and there are a few of the same measurements/color as the one I need (I know this would still be a VERY wild guess, which is why I haven't tried just replacing them and seeing what happens)

The ones I'm trying to replace were originally 0201 (0603) 100pF 50V NP0 +/-2%

[fzabkar]

AFAIK, most HDD caps either bypass a supply rail, or they filter the outputs of the various onboard linear or switchmode supplies. The former would probably have values of the order of 10nF while the latter would be more like 10uF.

NPO ceramics have a zero tempco. The only place I would think of looking for such a capacitor would be the two tuning caps in the vicinity of the crystal, and that would be adjacent to the MCU. I could be wrong, but a value of 100pF seems a bit high for these.

[Lord Kamina]

AFAIK, most HDD caps either bypass a supply rail, or they filter the outputs of the various onboard linear or switchmode supplies. The former would probably have values of the order of 10nF while the latter would be more like 10uF.

NPO ceramics have a zero tempco. The only place I would think of looking for such a capacitor would be the two tuning caps in the vicinity of the crystal, and that would be adjacent to the MCU. I could be wrong, but a value of 100pF seems a bit high for these.

Thank you very much. Not really good news but impeccable answer nonetheless.

[fzabkar]

AIUI, there should be at least two PLLs, one for the SATA data link and another for the data clock associated with read/write channels. It may be that these PLLs use precision capacitors for their timing. I wouldn't be able to identify these caps for you, although they would be attached to the MCU, if they exist.