May 31st, 2018, 20:12
May 31st, 2018, 21:25
May 31st, 2018, 22:20
June 1st, 2018, 12:29
June 2nd, 2018, 18:56
fzabkar wrote:Zero-ohm resistors R100 and R101 appear to be connecting PCB ground to the metalwork of the USB connector. I can't see how they could possibly affect the circuit. Instead I'd be checking the two 1R0 resistors (R1 & R3, 1 ohm) for continuity.
I'd also confirm that the crystal oscillator (U6) is oscillating.
U4 appears to be a switchmode regulator IC. I expect that the junction of L1 and C17 would the Vcore supply for the flash controller.
HaQue wrote:Is C8 sldered ok? hard to tell, may just be shadow on the bottom.
Minho wrote:I would also try removing/re-soldering the micro-controller. If the drive took physical damages (broken connector), it's possible that some of the pads beneath the IC legs have cracked. Removing the controller will allow you to see if the pads are in good condition. Any damaged pads can be repaired.
June 2nd, 2018, 19:38
June 3rd, 2018, 18:23
AgreedHaQue wrote:Sometimes BGA balls get lifed if drive was bent or stressed.
June 4th, 2018, 10:11
Minho wrote:I would also try removing/re-soldering the micro-controller. If the drive took physical damages (broken connector), it's possible that some of the pads beneath the IC legs have cracked. Removing the controller will allow you to see if the pads are in good condition. Any damaged pads can be repaired.
June 4th, 2018, 12:00
jeremyb wrote:AgreedHaQue wrote:Sometimes BGA balls get lifed if drive was bent or stressed.
June 4th, 2018, 12:23
fzabkar wrote:Can you tell us the markings on U4?
Can you measure the voltages across C23 (V1) and C17 (V2)?
June 4th, 2018, 16:16
June 4th, 2018, 16:44
June 4th, 2018, 17:03
fzabkar wrote:It appears that U4 (RT8010) is not getting an input voltage (Vin, pin 3). We need to find where Vin is coming from. I suspect that the flash controller may be reducing the USB +5V input to +3.3V via an internal LDO regulator. Then this +3.3V supply would be applied to the Vin pin of U4 to generate the controller's Vcore supply.
I would confirm that +5V is present at each end of resistors R1 and R3 (1R0). I would then use the multimeter's continuity function to determine which pin of the controller is connected to the Vin pin of U4, if any. If the controller is receiving +5V but is not outputting +3.3V, then it would be suspect. Alternatively, U4 could be powered from the +5V input, so I would test for that possibility as well.
RT8010GQW, Richtek, 1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter, 2.5V to 5.5V input, marking ET, adjustable:
http://www.richtek.com/assets/product_file/RT8010=RT8010A/DS8010A-10.pdf
June 4th, 2018, 17:26
June 4th, 2018, 17:42
fzabkar wrote:What are the voltages across C104 and C8? What are their resistances?
June 4th, 2018, 17:56
ddrecovery wrote:fzabkar wrote:What are the voltages across C104 and C8? What are their resistances?
Both caps read 0.25v.
Can I measure resistance of a Cap while its on the board?
Diode mode readings of both these caps is 591.
June 4th, 2018, 18:14
fzabkar wrote:I suspect that the flash controller may be reducing the USB +5V input to +3.3V via an internal LDO regulator. Then this +3.3V supply would be applied to the Vin pin of U4 to generate the controller's Vcore supply.
June 4th, 2018, 18:15
June 4th, 2018, 18:19
ddrecovery wrote:4.3v, not sure why its not 5v.
June 4th, 2018, 18:25
ddrecovery wrote:4.3v, not sure why its not 5v. This is also wired to a new connector so we can rule that out.
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