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 Post subject: fzabkars - Western digital PCB Research Questions .
PostPosted: May 22nd, 2015, 14:54 
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Posts: 2690
Location: CDRLabs @ Chandigarh [ India ]
Well Frank ,
I read that article with great interest -> http://www.hddoracle.com/viewtopic.php? ... 119&p=5033 .And i found out that you were assuming the arrangements of the 12 Volts Sections Like This

Code:
                             .---------.
    +12V  o-----------+------|         |
                      |      |  motor  |----> spindle motor
                   D4 -      | control |
                      ^      |         |
               ___    |      |         |----> VCM
    Gnd   o---|___|---+------|         |
                             ----------'
               R64


But in Turn It was Like This

Code:
                    .--------.
    +12V  o----+------|        |
             |      |        |
             -  D   |        |
             ^      |        |
             |      |        |
            .-.     |  HDD   |
            | |     |        |
            | | R   |        |
            '-'     |        |
             |      |        |
    Gnd o----+------|        |
                    '--------'


I would like to add a point that the resistance that you actually assumed to be on the left side towards ground should actually be on the right towards the motor control if you want the TVS to be very effective and not have any affect to hdd circuit .If the TVS shorts and the hdd pcb is subjected to more energy by a powerful smps the resistance will open if it actually is made by a good company and adheres to quality and specs .I have and share the same observation for 5 volts .I will definately read more of yours and spildits research and pour some of mine time to time

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Amarbir S Dhillon , Chandigarh Data Recovery Labs
Logical,Semi Physical And Physical Data Recovery
Website-> http://www.chandigarhdatarecovery.com


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 Post subject: Re: fzabkars - Western digital PCB Research Questions .
PostPosted: May 29th, 2015, 3:09 
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Joined: October 3rd, 2005, 0:40
Posts: 2683
Location: Hungary
Hello,

I thought i already addressed this situation in around 2010 but can't find those posts... Basically over voltage protection on WD boards is useless, they seem to have no idea what a TVS is for...

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 Post subject: Re: fzabkars - Western digital PCB Research Questions .
PostPosted: May 29th, 2015, 7:59 
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Joined: August 15th, 2006, 3:01
Posts: 2690
Location: CDRLabs @ Chandigarh [ India ]
pepe wrote:
Hello,

I thought i already addressed this situation in around 2010 but can't find those posts... Basically over voltage protection on WD boards is useless, they seem to have no idea what a TVS is for...


And Pepe Sir ,
I Miss You More Then Anyone Else On The Forums .If You People Will Not Pass It On To Us Slowly How Will We Gather The Experience Etc From You Senior People .I Do See You Off And On On Acelab Forums Though .

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Amarbir S Dhillon , Chandigarh Data Recovery Labs
Logical,Semi Physical And Physical Data Recovery
Website-> http://www.chandigarhdatarecovery.com


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