Hi! I'm trying the most help I can, I'm a newbie to HDD recovery and one of the first cases I have is this Caviar WDAAJS (Main controller is 88i8845C-BHG2) showing up on FLIR camera as shorted.

Needless to say, HDD does not even appear in file explorer, BIOS, etc. It does not even spin!

What can I do in this situation? What are my chances? If the controller shows a short and I resolder the IC to another PCB board most likely it will be the same scenario, right?

An ideas, welcome

Measure the resistances between ground and each of Q1, L2 and L1. If there are no shorts, then measure the voltages at those same components.

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A backup a day keeps DR away.

This. And also test D3 and D4.

more precisely? what component is getting hot?
the bad news with these drives is that the OV protection is crap, the fuses protect the TVS diodes, not the circuit, so an OV can easily run down to the preamp and kill it. THis is a dangerous thing and can seriously damage the data if not noticed.

pepe

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Adatmentés - Data recovery

Hello again



These are the readings:
L1:42kOhms
L2: 44kOhms
Q1:6MOhms at Base 10Khms at Emitter



These are the readings:

D4: 1.76v
D3: OL both sides

The chip getting hot is the 88i8845C-BHG2, the main controller

It doesn't appear that there are any shorts.

There should be +3.3V at the emitter of Q1. The voltages at L1 and L2 should be +1.2V and +2.5V, IIRC.

The anode of D2 should be -5V. This voltage may be present briefly at power-on and then drop to 0V.

I don't understand why D3 is OL in both directions. R64 and R67 should measure 0.0 ohms. If R67 is open, then this would suggest that there was an overvoltage at the 5V input. However, this is very often accompanied by visible damage to the SMOOTH chip.

Also, the resistance at the Vcore supply (L1 or L2) is normally ~100 ohms on the 200 ohms range.

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A backup a day keeps DR away.

Take off D3 diode and test does it spin up after this.