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gameboybin
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: July 9th, 2026, 19:03 
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Joined: April 17th, 2022, 22:39
Posts: 234
Location: Vietnam
fzabkar wrote:
A Vcore voltage of 1V is OK, as I understand it. The supply voltage seems unaffected by the low resistance. I just don't understand why your two Vcore resistance readings differ.


What can a half bad resistor do?? I mean something is definitelly affecting the Vcore resistance at the resistors
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fzabkar
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 10:14 
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Joined: September 8th, 2009, 18:21
Posts: 17038
Location: Australia
gameboybin wrote:
fzabkar wrote:
A Vcore voltage of 1V is OK, as I understand it. The supply voltage seems unaffected by the low resistance. I just don't understand why your two Vcore resistance readings differ.


What can a half bad resistor do?? I mean something is definitelly affecting the Vcore resistance at the resistors

Measure the resistance between the L2 inductor and your "shorted" capacitors. Is it 0 ohms?

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gameboybin
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 15:15 
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fzabkar wrote:
gameboybin wrote:
fzabkar wrote:
A Vcore voltage of 1V is OK, as I understand it. The supply voltage seems unaffected by the low resistance. I just don't understand why your two Vcore resistance readings differ.


What can a half bad resistor do?? I mean something is definitelly affecting the Vcore resistance at the resistors

Measure the resistance between the L2 inductor and your "shorted" capacitors. Is it 0 ohms?


They have from 190 to 220 ohms

Attachment:
SHORTING POINTS 200.JPG
SHORTING POINTS 200.JPG [ 555.83 KiB | Viewed 173 times ]


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gameboybin
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 15:32 
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Joined: April 17th, 2022, 22:39
Posts: 234
Location: Vietnam
gameboybin wrote:
fzabkar wrote:
gameboybin wrote:
fzabkar wrote:
A Vcore voltage of 1V is OK, as I understand it. The supply voltage seems unaffected by the low resistance. I just don't understand why your two Vcore resistance readings differ.


What can a half bad resistor do?? I mean something is definitelly affecting the Vcore resistance at the resistors

Measure the resistance between the L2 inductor and your "shorted" capacitors. Is it 0 ohms?


They have from 190 to 220 ohms

Attachment:
The attachment SHORTING POINTS 200.JPG is no longer available


I have this Strange resistor. It is not shorted to ground. However when measured between the inductor. It beeps and shows 1 ohm on 1 side and 200 on the other
Attachment:
2 FRONT.jpg
2 FRONT.jpg [ 474.8 KiB | Viewed 165 times ]


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Lardman
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 15:40 
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Joined: November 7th, 2020, 5:31
Posts: 1295
Location: United Kingdom
Can you take a better picture so we can see what the component you mean and the circuit board / traces around it.

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gameboybin
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 15:59 
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Joined: April 17th, 2022, 22:39
Posts: 234
Location: Vietnam
Lardman wrote:
Can you take a better picture so we can see what the component you mean and the circuit board / traces around it.


Here you go

FRONT
Attachment:
BETTER FRONT.jpg
BETTER FRONT.jpg [ 1.06 MiB | Viewed 159 times ]


BACK
Attachment:
BETTER BACK.jpg
BETTER BACK.jpg [ 1.08 MiB | Viewed 159 times ]


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fzabkar
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 17:43 
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Joined: September 8th, 2009, 18:21
Posts: 17038
Location: Australia
I think that the anomaly can be explained by power sequencing.

I believe that U6 is a dual step-down converter, MP5506, by Monolithic Power. Unfortunately I can't find a datasheet.

Q1 and Q2 are N-channel MOSFETs (DMG6968U). They appear to be switching the two outputs of the buck converter (1.0V and 2.9V) on and off under the control of U6. The reason that you measure different resistances is that you are measuring different sides of the MOSFET switch when it is turned off. When then SSD is powered on, the switches are closed (MOSFETs turned on) and the voltages are the same on both sides (Drain and Source). In fact, please measure the voltage at the VCC_NAND-Switched test point.

It would appear that one of those capacitors is leaky, but not shorted. This does not prevent the Vcore supply from coming up.

In short, I believe the low resistance is a distraction and the actual problem is firmware related.


DMG6968U, Diodes Inc, N-ch MOSFET, marking 2N4, SOT23:

https://www.diodes.com/datasheet/download/DMG6968U.pdf


Attachments:
MP5506_switched_outputs.jpg
MP5506_switched_outputs.jpg [ 593.39 KiB | Viewed 125 times ]

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fzabkar
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 18:15 
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This is U5.

MP2136, Monolithic Power, stepdown converter, 2.5V - 6V Input, 2MHz, 1A, marking 6Q, QFN6:

https://www.farnell.com/datasheets/2914869.pdf

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fzabkar
 Post subject: Re: ADATA Premier Pro SP900 shorting everywhere
PostPosted: Yesterday, 18:44 
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Posts: 17038
Location: Australia
Code:
         .--------------------------.
         |                          |
         |                          |
         |            .------.      |         .-----.
         |            |      |      |         |     |
         |           ---    ===     |        ---   ===
   .-----------. L3  ---    GND     ===      ---   GND
   |   on/off  | ___  |             |^| Q2    |
   |           |-UUU--+-------------+|+-------+-------o   VCC_NAND_switched
   |           |    VCC_NAND
   |           |
   |  MP5506   |
   |           |
   |           | ___ Vcore
   |           |-UUU--+-------------+|+-------+-------o   Vcore_switched
   |   on/off  | L2   |             |V|       |
   '-----------'     ---         Q1 ===      ---
         |           ---              |      --- 20 ohms
         |   210 ohms |               |       |
         |            |               |       |
         |           ===              |      ===
         |           GND              |      GND
         |                            |
         '----------------------------'

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