SMOOTH combo on SABRE

[areus]

Hy!

I have a Maxtor Sabre drive (6B200M0 - Diamond Max 10), what had a burnt Smooth combo IC (L7250E 1.2, the PCB is T3GBA).
I changed the combo, but the drive wont spin up. I checked the diodes, changed the Voltage reg. (Q500 - 2DPS20V) the FET too, but still nothing...
On the PCB i found a -5V pad....i measured them, but only +0.2V (RMS).

My question is: which components can be wrong? I must check the SMD resistors too?

[quasimodo]

sounds like motor controller. Are you sure that the Smooth IC is soldered corrctly and did not overheat during solder process?

[rameez]

sometimes resistance in the 5v line gets devalued check them to .

[shaun]

Or the head amp (which actually needs those -5V) is shorted and thereby overloading the -5V reg.

[pepe]

Hi,

Or the main processor is gone, or there's no 3.3V alimentation or.... anything. U need an oscilloscope and check everything systematicaly.

pepe

[areus]

Thank you for all the quick reply...

My bigest problem is: there is no sound:( When i connect it to the bridged IDE (SATA->IDE), only the BUSY flag is active.

On the back of the SMOOTH IC is a big area (maybe some GND connection...)...how can i solder-desolder them correctly ? Every pins are ok. I got the new IC from a donor PCB (it has only a cpu crash). The PCB was heating whit a small aluminium plate on the back side at the combo. At 210°C (i measured this temp...) i toke the IC quickly from the board. This solution was needed for the desoldering on Smooth's back side connection. (i saw this solution by changeing big BGA ic, like motherboards northbridge....works ok, and very quick ). The re-soldering was similar. The whole procedure needs only 5-6 min only.