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آموزشی: مقاله :زبان اصلی هارد دیسک و اجزای آن و قطعات و چگونگی ارتباط آن ها

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[h=3]What is a preamplifier?[/h]​
It is a small chip, located on a head stack. In old hard drives the preamplifier is usually multi-pinned; new models are made with an open-frame type of preamplifiers that attached either by using conductive adhesive directly on contact areas or by soldering accordingly to BGA principles (Figures 1, 2).

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Figure 1 — a head stack with an open-frame preamplifier (Hitachi ATMR series, 2.5-inch drive)


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Figure 2 — a frame-type preamplifier (Seagate Barracuda IV drive)
Working with preamplifiers always includes some difficulties, because, practically, they can not withstand static discharges. If re-soldering is needed, one should follow a number of rules to protect a preamplifier from static damage caused by careless finger touching. Simple protection includes: ground connections for the drive, for a soldering station, for the repairer; and using a 12-volt soldering station.​
[h=3]How to tell that it’s really a head trouble?[/h]​
In fact, it is more likely a philosophical question. Even after looking inside the drive there still can be no definite answer — in this case specialists often count on their own experience and on software. For example, PC-3000 software can accurately detect weak head on IBM, Western Digital, some Seagate drives, by using service area surface checking functions.
Old hard drives with their obvious reliability (here we mean 20...512 MB drives), are gradually dying; one of the reasons for that is exactly a heads’ problem. On the Figure 3, a “lifted​
 

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[h=2]Hard Drive Errors and Replacements[/h]


Many poor quality hard disk drives manage to get to market. This is especially true with "bleeding edge" models. These drives often suffer failures. For the average individual or corporation, this is problematic enough (and worse when a backup has not been made). For the forensic analyst, this can be devastating, at least if you do not know what must be done.​
A common problem is a preamplifier failure. This failure will generally result in the drive creating a clicking or hissing noise. Another cause of this sound can come from a head stack failure. In this post I will detail some of the issues and steps associated with the replacement of a drive head or preamplifier.​
The first thing is to access the drive internals. This will invalidate your warranty, but when conducting a forensic examination, the ability to have the drive replaced is of small concern. First, ensure that you have a clean work area.​
A clean room is not necessary. Dust will cause long term damage to the drive, but this is long term. As long as the level of dust is low (such as in a standard computer room), the issue will not impact the forensic process (contrary to popular belief). You will require a set of Hex drivers or other security drivers (you can see what type is required by looking at the screws on the top of the drive).​
Several of the screws will be covered (see figure 1) with the manufacturers label. Do not force the lid off the case, but rather ensure that you have removed all of the screws (and the case will then come off easily). The drive I have used in this post has four hidden screws, some drives have more or less. Rubbing the top of the case with your fingertips will help you locate these.​
figure1.jpg

Figure 1 - Opening the drive (note the screw under the label)
These will not be the usual screws such as a Phillips or chisel head screwdriver. You will require a selection of screw driver heads (see figure 2). These are readily available from any good electronics or tool store.
figure2.jpg
Figure 2 - A selection of tools.
Once you have opened the case, you will see the drive internals. Figure 3 (below) has the location of the preamplifier (figure 4) circled in yellow and the head stack (figure 5) circled in green.
figure31.jpg
Figure 3 - The open drive
Preamplifier
The preamplifier is a small integrated circuit chip. This will be attached to the head stack on a small PCB (printer circuit board). To remove this you will most likely need to remove the main PCB. This may require removing the screws on the opposite site of the drive holding the PCB on (more generally in older models). This step will not be required in most cases, but this has been removed in figure 6. The drive used in this example does not require this step, but I find this easier as removing the small metal plates makes removing the magnet (and hence the head) far easier. Like many new drives, the platter is held in place using a strong magnet. This magnet is on the left in figure 7 below.​
Take Care: The magnets will pull towards each other and if you slip you can damage the drive.​
Ensure that you have a good sized clear and open space to place the components (an anti-static mat is a good idea). Start placing the components and the screws associated with them from the left and work towards the right. This will ensure that you do not miss anything when you reassemble the drive.​
Note: Do Not touch the platter and ensure that you use an anti-static band.
figure4.jpg
Figure 4 - The preamplifier chip
Slowly extract the head stack. Take care. If you touch the platters you will damage the data. I have a specialized vice for this these days, but it is possible to do this without one.​
I suggest that you buy 20 or 30 old drives (these can be sourced for as little as $5 each). Practice on these until you can remove the head stack without touching the platter or damaging anything. When you have done this, you will be ready to work on a real drive.
figure5.jpg
Figure 5 - The drive's head stack
Note in figure 5 the location of the preamplifier on the head stack (circled in yellow).​
Older hard drives commonly have a pinned chip. Newer drives (such this the example) attach the preamplifier with either conductive adhesive to the contact areas or less commonly by soldering this on. My fingers are far too large and I will personally replace the entire preamp PCB rather than resoldering a preamp. And it is also easier to just do this for a glued chip.
figure6.jpg
Figure 6 - The rear PCB
Where do you get the replacement?
Well this is simple (at least in reasoning). Replacement parts are best and most easily obtained from old (but working) drives. Remember, we do not care about the long term. The issue is not getting another year from the drive, but just long enough to image the drive.​
figure7.jpg

Figure 7 - the components as disassembled
The difficulty comes when you can not locate an exact match to the drive, but there is something to repair. In figure 8, a lifted head is displayed.
figure8.jpg
Figure 8 - A lifted drive head
Head damage is problematic
When a drive head has lifted or broken off, anywhere on the platter that it has touched will lose data (so you will need to image the drive skipping errors).​
What if there are no replacement drives is to be found?​
Sometimes there will not be an exact match for the damaged drive. This means that you will not be able to replace the head unit as a whole. In this case, similar drives can be cannibalized. I will not include a lesson on soldering here, but this is another skill that requires practice to do well.​
The best way to analyze a preamplifier is using a COM-Terminal program. This part is simple (as even hyperterm satisfies this). Finding the pin-out can be difficult (these exist but are not always easy to find). For instance, iHDD.ru has several of these (in Russian). For instance see the link regarding the Seagate (BARRACUDA 7200.7 160G ST3160021A ).
You can also learn the click sequences for selected drives (more on this in a later post). For instance the following preamp failures will result in the following:​

  • [*=left]Western Digital: 2 loud clicks and the spindle will stop.
    [*=left]Maxtor: Continuous clicks for 30 seconds
    [*=left]Quantum: 2 loud clicks, the spindle will speed up and 4 clicks.
Find the problem and you can fix it.
The final step is to reassemble the entire drive unit and proceed to imaging. The secret to doing this is practice. Old drives are inexpensive, all you need is time (oh and some basic tools).​
More later...
Ed. Note:
For additional training on hard drive repair and it's role in digital investigations, check out SANS Sec 606 with Scott Moulton.

 
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pese

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Hard Drive Circuit Board Replacement Guide or How To Swap HDD PCB



Replacing a defective hard drive circuit board is not an easy swap. The new PCB must be adapted for your hard drive. Without the necessary steps to adapt to the new circuit board, your hard drive will not function properly and data will not be accessible.​
There are few things to know before you proceed:
1. Not every hard drive failure is due to a bad PCB—only about 25-30% of data loss occurs due to failed electronic components. Even what seems to be an obvious sign of a PCB failure could be a completely different (often mechanical) issue. If time and data are important, consider sending us your hard drive for our diagnostics and PCB adaptation services.​
2. When a circuit board fails, you may need to take a few additional steps to make sure your hard drive is working with the new PCB. Read this entire HDD Circuit Board Replacement Guide below to understand the process, and improve your chances of successful data retrieval.​
Step 1. Understanding PCB Firmware

Most hard drive circuit boards possess ROM, NV-RAM, or a controller chip that holds unique data required to access the hard drive system area. We call this data “PCB firmware​
 
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ard Disk Repair Basics



If you have highly valuable data that you wish to recover, then you should consider recovery specialists because the task requires specialist equipment and software. A hard disk drive repair and recovery is performed by the most qualified and experienced professionals, and if you value your data then these are the only people to trust for the task.​
In most cases, a hard disk is non-repairable if it has failed or is failing. Laboratory grade environments using specialist tools and equipment are typically required to carry out hardware repairs. Repairs are normally expensive and carried out only for data recovery purposes.​
If you have a disk that is showing bad sectors, you still have a choice to repair or replace. The best thing to do is to replace it straight away. Although these types of errors may be repairable carried out by software, many people who value their data will replace the drive entirely.​
This page looks into some of the hardware faults that could manifest and some basic places to check. It is by no means a repair guide; however, people tell me that they found it useful.​
Clicking Sound


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The actuator arm moving back and forth trying to read the System Area (SA) creates the clicking sound normally heard once during start-up. The SA is stored on the outermost edge of the disk, but there is also a backup of it on the innermost edge or sometimes in the middle of the disk, depending upon the manufacturer.​
A continuous clicking sound often means that the SA including the backup is unreadable. Without the initialisation parameters stored in the SA, the disk cannot continue to operate and therefore automatically shuts down. This type of fault is repairable just long enough to recover the data.​
The clicking sound can occur due to a number of different reasons. It could be due to the heads having failed, or physical damage to the SA cylinders. Sometimes the preamplifier chip fails and cannot relay the data to the main PCB. Sometimes it could even be a firmware issue.​
Hard Drive Block Diagram


23.gif

A typical hard drive consisting of subsystems forms a complex electronic device. On modern drives, the subsystems are within one large chip, which provides the advantage of better self-testing and power management.​
The microcontroller is normally the first to start-up and carries out a self-checking routine. The actuator and spindle motor are generally the last to receive power. All of these precautions are to safeguard the data stored on the drive.​
Power Supply Check - PCB


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In the past, sub-systems divided each function at chip level and therefore, it was possible to perform component level repair to make the drive operational again for data recovery.​
If the drive is dead, check for +5 V and +12 V entering the PCB and the power section. Most drives have Transient Voltage Suppressor (TVS) diodes. The diodes shown above within the red rectangle perform that function.​
If the spindle does not turn then it may be a good idea to check the servo chip and the stepper motor driver chip.​
Bad Block Table

Modern drives use microcontrollers with combined functionality. This reduces the PCB component density as well as allowing for cheaper and quicker manufacturing. In such cases, PCB repair becomes difficult and it is more cost effective to perform a PCB transplant from an identical drive to make the faulty drive operational again.​
All modern drives have a bad block table that is unique for each drive and stored on a flash memory chip. As a result, a PCB transplant does not always work because the information in the bad block table will be different.​
As you can see, many things can go wrong on a drive and therefore it a good idea to get the best drive possible.​
The drive is the most important part of your computer system because it stores all your data and hard work. This is the one part where you must get the best quality component you can afford.​
 

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این هم سر فصل تعمیرات هارد دیسک که فراره تو کتاب خودم در آینده به زبان فارسی به طور کامل بیان کنم.

DATA RECOVERY PHYSICAL COURSE CONTENT CHAPTER WISE

Module 1 Logical Data Recovery Training


1 Introduction to Storage Device
2 Hard Disk Data recovery common problems​
2.1. LOGICAL DATA RECOVERY PROBLEMS
(Disk detected in bios are main logical problems)​
2.2 PHYSICAL PROBLEMS (disk not detected in bios are main physical problems)​
2.3 MECHANICAL FAILURE PROBLEMS​
3) Understanding hard disk structure​
4) Understanding data stored in hard disk & Microsoft files structure​
5) Formatting Partition & booting process of hard disk​
6) Data recovery Software used for purpose with features​
Module 2 Physical Data Recovery Training


7) Internal Parts of Hard Disk Demo Hard disk from inside​
Inside Parts Identify Disassemble SATA 3.5 Drive 1tb St31000333as


8) Donor Selection of Different Hard Disk​
9) Data recovery instrument detail and used detail with demo on opening hard disk​
10) 3.5​
 
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این هم عرفی یک مولتی متر خوب برای تعمیرات بورد هارد دیسک

Digital Multimeter Pro. Free Shipping Worldwide By DHL Express

Digital Multimeter Pro. is one professional and easy-to-use digital product repair tool used to diagnose the voltage, resistance, electric current and test whether the circuit is intact or whether there is a break.​
Digital Multimeter Pro. is one must-have repair tool if you are offering PC repair services, hdd repair services, data recovery services and even after-sale support for other electronic products, it can be used for home use for household appliances as well.​
285.jpg

Within our hdd repair and data recovery cases, we usually use this Digital Multimeter Pro. to handle the failure of PCB or PCB related electronic components to restore it so that the patient hard drives can be diagnosed more accurately for finding out the best solution.​
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Features of This Digital Multimeter Pro:


  • [*=left]Stremline design with antivibration protection cover;
    [*=left]Clear testing information display on a big screen;
    [*=left]Metallic shield plate with antimagnetic and interference-free design;
    [*=left]The power is kept on for normal operations instead of auto power off;
    [*=left]Arc-fault circuit protection;
    [*=left]New battery gate design for easier battery exchange;
    [*=left]Self-restoration protective tube with protective circuit.
Digital Multimeter Pro. Measuring Range And Accuracy


  • [*=left]Volts d.c.:200mV/2V/20V/200V/1000V ±(0.5%+3)
    [*=left]A.C. voltage:2V/20V/200V/700V ±(0.8%+5)
    [*=left]D.C.current:200uA/20mA/200mA /20A ±(1.5%+3)
    [*=left]A. C. current:20mA/200mA/20A ±(1.5%+5)
    [*=left]Resistance :200Ω/2kΩ/20kΩ/200kΩ/2MΩ /20MΩ ±(0.8%+5)
    [*=left]Other Functions:diode testing,triode testing,continuity buzzer, low-voltage display, data retention,Auto power off, etc.
Digital Multimeter Pro. Technology Indicators:


  • [*=left]Input Resistance :10MΩ
    [*=left]Sampling Rate:3 Times/s
    [*=left]A.C. Frequency Response:40-o
    [*=left]Operation Mode:Manual measuring
    [*=left]Zoom Extents:1999
    [*=left]LED Size:55×37mm
    [*=left]Power: 9V (6F22)
 

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[h=3]Logical Recovery[/h]
Logical failure occurs when the drive’s file system driver gets corrupted or erased. Logical data recovery can also be needed if accidental formatting has occurred.​
[h=4]Types of Logical Failure[/h]
File System Corruption​
When the file system (NTFS, FAT, HFS) driver gets corrupted, the data on the device will become inaccessible.​
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NTFS and FAT file systems (Windows)​
For NTFS and FAT file systems, the Master File Table remains the backbone of the folder structure. It contains an index of all the files on the volume, consisting of columns of “attributes​
 
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