August 7th, 2016, 16:03
I suspect that the MSP430V952 microcontroller may control the power sequencing for the PCB. It would be interesting to see whether it is getting hot and whether it is powered from the OAH LDO regulator.
Edit #2: Measure the resistance between the 0.9V point and ground.
August 7th, 2016, 16:21
August 7th, 2016, 16:49
Their Vin is at 5.0V but EN is low at 0V. For the ODH, enable is 0V as well and PVIN/AVIN are ~0.3V.The QY device is a 2.5V regulator. Its input voltage is 0V. Can you check whether the RAU, ODH, and MP5505 parts are also missing their input voltages?
Good call, seems we're good. Only V1 measures about 50Ohms to ground, the others are much higher.One other thing to do would be to measure the resistance between ground and the outputs of each of the regulators. This will tell us if the flash controller or any of the NANDs are shorted. If any of these ICs are damaged, then there would be no point in continuing.
Can you measure resistances Rx and Ry, and voltage Vy, in the MSP430 image?
Between Vy and +5V on SATA connector I measure about 1.5M Ohm. Between +5V on SATA connector and PMOS drains is 25.0 Ohm.I suspect that Vy should be +5V. If so, then could you test the resistance between this point and the SATA +5V pins and the Drain pins (output side) of the power MOSFET?
It appears that pin #23 may be the MCU's supply pin, or could it be pins 27, 29 or 30? Are any of these pins shorted to ground?
Is the adjacent component also a 10 ohm resistor?
August 7th, 2016, 17:17
August 7th, 2016, 17:48
fzabkar wrote:The OAH regulator's input voltage of 4.45V must be coming from the +5V supply via an additional component. Perhaps the mysterious Schottky diode is in series with this supply?
I've done a quick test and found that at least two of the RAU regulators have their EN pin directly connected to one of the MCU pins. Since MCU and regulators are on different sides of the PCB it's somewhat hard to probe but I'm sufficiently confident to say the MSP430 needs replacement! I'll see if I can source it and report back once I've replaced it.In short, ISTM that the MSP430 is the power sequencer/controller for the PCB. I expect that each of the regulator EN pins will connect to the MCU's I/O pins. This would be the proof that the MCU is the heart of it all.
August 7th, 2016, 18:00
zzattack wrote:Edit: actually, I may need some help replacing. Since this isn't a passive component, I probably need the firmware in the microcontroller don't I?
August 7th, 2016, 18:07
August 7th, 2016, 18:16
zzattack wrote:About device selection, it seems the difference between MSP430x11x2 and MSP430x12x2 is SPI/UART availability in the latter and the difference between 1x22 and 1x32 is flash memory size. I'm guessing the 1232 is the most compatible one and should always work. Does that make sense or would I need the exact replacement?
Can I go wrong with picking the 'largest' device from the device family, i.e.
August 7th, 2016, 18:20
zzattack wrote:Replacing the MOSFET shouldn't be a problem at all.
According to the datasheet the MSP430 has 'code protection'. The flash memory can be programmed via the JTAG port, the bootstrap loader, or in-system by the CPU. Now I wonder if the code protection applies to both JTAG and the bootstrap loader.. I'm starting to fear we're out of luck.
August 7th, 2016, 18:31
August 7th, 2016, 18:33
August 7th, 2016, 18:35
BTW, if you have a CCD scanner (not CIS), this produces much better images than a typical camera.
August 7th, 2016, 18:42
August 7th, 2016, 18:48
August 7th, 2016, 18:52
My bad, I should clarify: the 4 enable pins all trace back to different pins on the MSP430.fzabkar wrote:If all chips use a common enable pin, then that makes it a lot easier. Perhaps we don't need to worry about power sequencing. Would it be OK to add a 1K (?) pullup resistor between the EN pins and the 3.3V supply?
I agree, the 5505 seems only for power storage/backup functionality, so I doubt it's important for normal operation.The MP5505 has its own enable pins. Do you think it would matter if this chip were switched off? AIUI, its function is to provide a voltage for the backup capacitors and to keep the SSD alive in the event of a sudden power failure.
August 7th, 2016, 18:58
August 7th, 2016, 19:00
August 7th, 2016, 19:13
August 7th, 2016, 19:25
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