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Data recovery and disk repair questions and discussions related to old-fashioned SATA, SAS, SCSI, IDE, MFM hard drives - any type of storage device that has moving parts
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How to unhide preamp on Seagate?

April 5th, 2020, 15:45

I have following problem: this is preamp of ST31000524AS
Chip is covered with something black... so there are no markers visible.
This cover looks like glass/ceramic, gives reflection like a mirror, is hard and I cant' remove it with a cutter. Many preamps are covered like that, but till now I have no need to remove it...
I tried with hot-air at 150 C, at ->>> 450 C and nothing happened with it... I heated it to 450 C and put it to cold water in hope it will break up, if it's a glass.... nothing happened.
I thought about hydrofluoric acid, as it dissolves glass, but first I havent' it now, and second may be there is a simpler method.
I'm sure some of you have an idea, how to remove this shit not breaking the chip completely :)
I dont' need working chip, I just want to identify it.
PREAMP_ST31000524AS-fragg.jpg

PREAMP_ST31000524AS_reflection.jpg
PREAMP_ST31000524AS_reflection.jpg (34.81 KiB) Viewed 2115 times

Re: How to unhide preamp on Seagate?

April 5th, 2020, 21:56

eaxi,

What's the point?
All the same, you will not find the documentation and buy a chip anywhere.
On ST31000524AS the Pharaohs there are a whole bunch of chips:
PH4-T AGA3-B
PH4-B AG-B
BR4-T TIAA-B
BR4-P TIAA-C
PH4-C LSIA3-C
PH4-B AG-B
PH4-B TI-B
PH4-C TIAA-C
PH4-C LSIA3-C
PH4-T AGA3-B
PH4-B AG-B

Re: How to unhide preamp on Seagate?

April 6th, 2020, 11:06

If you need to identify preamp because you need to swap heads, then you could find its value inside pcb rom.

Re: How to unhide preamp on Seagate?

April 6th, 2020, 19:09

Of course, I've read a sticker and I've read PREAMP ID from ROM
Sticker: TIAA
ROM: 5801
I've attached both if someone is interested
But I need to identify the chip directly to be sure that preamp is original
ST31000524AS_JC4B-sticker.jpg
ST31000524AS_JC4B-sticker.jpg (56.68 KiB) Viewed 1962 times

ST31000524AS_JC4B.ROM.zip
(222.53 KiB) Downloaded 62 times

Re: How to unhide preamp on Seagate?

April 7th, 2020, 4:05

you mean by SN or what?

You can read preamp id in terminal...

pepe

Re: How to unhide preamp on Seagate?

April 7th, 2020, 5:56

Hello,
All This s Not Required ,Do as The others said and you yourself showed the photos on the sticker in your next post so its already clear ,Thats a crystal you will achieve nothing by removing it

Re: How to unhide preamp on Seagate?

April 7th, 2020, 8:45

Noone had problem with such cover? :(
@pepe, Ctrl-L gives output originated from SAP, which I have already read directly from ROM
@Amarbir: have you ever removed such cover and you know what's under the hood?
I have suspitions if HDA is original, so sticker or ROM readings, which just say "that's a Texas chip", are of no value.

Re: How to unhide preamp on Seagate?

April 7th, 2020, 9:28

no, ctrl-L reads the ID from the preamp, just confirmed it on a Sapta15.
pepe

and there is at least one other way.

Re: How to unhide preamp on Seagate?

April 11th, 2020, 8:36

eaxi wrote:Noone had problem with such cover? :(
@pepe, Ctrl-L gives output originated from SAP, which I have already read directly from ROM
@Amarbir: have you ever removed such cover and you know what's under the hood?
I have suspitions if HDA is original, so sticker or ROM readings, which just say "that's a Texas chip", are of no value.


Well,
Whats the need ,Thats what i am saying ,Its a silica glass type crystal ,Whats the point ?

Re: How to unhide preamp on Seagate?

April 11th, 2020, 17:56

The point is constantly the same from the beginning of this topic: where are manufacturers' markings of this chip. There are no anonymous chips. They must have markings, most have them clearly visible on the top, some have hidden inside the chip. So this is a question to people experienced in decapsulating, how to find markings here. This is NOT about how to read Seagates' "preamp ID" in terminal, SAP, sticker etc

Re: How to unhide preamp on Seagate?

April 11th, 2020, 18:01

eaxi,
It makes no sense to find out what kind of chip.
You take compatible heads and try.
With the complete coincidence of all the meanings, there is no guarantee that the heads will fit. Just poke.

Re: How to unhide preamp on Seagate?

April 12th, 2020, 7:12

eaxi wrote:The point is constantly the same from the beginning of this topic: where are manufacturers' markings of this chip. There are no anonymous chips. They must have markings, most have them clearly visible on the top, some have hidden inside the chip. So this is a question to people experienced in decapsulating, how to find markings here. This is NOT about how to read Seagates' "preamp ID" in terminal, SAP, sticker etc


Blahh ,
What are You Talking About ,If i make a pen drive and use a die/crystal on pcb and encapsulate it with a black die blob ,Were will it have markings [ NO WEREEEEEEEE ]

Re: How to unhide preamp on Seagate?

April 12th, 2020, 12:49

the die usually has some tiny marking even if it is encapsulated. But I still don't get where would you get if you knew the part number. It is perfectly irrelevant. Even if you find out the part number, it can be donor and not original, so the info is useless. On the other hand, the preamp id can be used instead of the partnum on the die.

Re: How to unhide preamp on Seagate?

April 12th, 2020, 15:35

pepe wrote:the die usually has some tiny marking even if it is encapsulated. But I still don't get where would you get if you knew the part number. It is perfectly irrelevant. Even if you find out the part number, it can be donor and not original, so the info is useless. On the other hand, the preamp id can be used instead of the partnum on the die.


Really ,
One In Hundreds Might Have ...
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