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 Post subject: WD My Book PCB for 4061-705094-001 rev.AA not spin up.
PostPosted: May 16th, 2020, 22:18 
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Joined: May 15th, 2020, 19:42
Posts: 3
Location: Japan
It's the HDD (My book essential) I used, but it's hard to turn on the power, and finally I can't turn on the power.
According to the investigation, it seems that 5V, 2.6V and 1.0V power is not supplied before U3 (IC).
The LED flashes if the power is not turned on for a while, but the power is not required.
Do you have any good advice?

Thanks for reading.

I hope it will give advice to other people in need.

Q2 (0v, 2.7v, 0v)
R90 (5.17V, 5.17V)



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 Post subject: Re: WD My Book PCB for 4061-705094-001 rev.AA not spin up.
PostPosted: May 16th, 2020, 23:30 
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Joined: September 8th, 2009, 18:21
Posts: 12748
Location: Australia
See …

http://www.hddoracle.com/viewtopic.php?f=112&t=1032

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 Post subject: Re: WD My Book PCB for 4061-705094-001 rev.AA not spin up.
PostPosted: May 17th, 2020, 19:37 
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Joined: May 15th, 2020, 19:42
Posts: 3
Location: Japan
Thank you for the advice.
Looking at the U3 (RT8060) data sheet, I feel that the resistance value from LX to FB is low.
LX-FB: 76KΩ (Good: 81k)
LX-GND: 26KΩ (Good: 34.4k)
I'll investigate a little more.


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 Post subject: Re: WD My Book PCB for 4061-705094-001 rev.AA not spin up.
PostPosted: May 17th, 2020, 19:56 
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Joined: September 8th, 2009, 18:21
Posts: 12748
Location: Australia
The 5V supply is OK. This supply then powers up the Vio regulator which generates the Vio supply for the bridge IC. The bridge IC has an internal PWM controller which then generates the Vcore supply from Vio.

So measure the voltages at the two smaller inductors. They will correspond to Vio and Vcore.

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