Voltage regulator on WD HDD

[Yuriy Manjilevskiy]

Voltage regulator is the chip on PCB which is responsible for allocation different voltage to some parts(elements) at PCB.
It has 7 pins. You can see this chip in red square:



We have noticed that there are 3 types of voltage regulator manufacture exists:

- IRU1239SC (International Rectifier)
- TLE4417 (Infineon)
- ST3L01 (ST Microelectronics)

Taking PCB off from HDD and giving Power On, we use multimeter we check voltage at each of the pin. We found that IRU1239SC and TLE4417 have same results.
But ST3L01 voltage regulator chip is different from first two.

We have checked voltage at IRU1239SC and TLE4417 and got next results below.
Approx. pin's voltage:

1 - 1.2 V
2 - 3.2 V
3 - 5 V
4 - 0 V
5 - 1.2 V
6 - 12 V
7 - 2.6 V
From this test we could see that pins 3 and 6 are input and rest of them are output.

For ST3L01 voltage regulation chip are the next results:
1 - 0 V
2 - 3.2 V
3 - 5 V
4 - 0 V
5 - 8 V
6 - 12 V
7 - 2.5 V


As a result we can definitely conclude that IRU1239SC and TLE4417 chips could be replaced by each other,
but ST3L01 voltage regulator could be replaced by the same chip only.

[Vadim]

This is PCB from WD HDD on the WD70Cxx chip. For this drives necessaty to launch Caviar Cyl 32 utility and Caviar Cyl 16 bit family.

[dmarques]

And this component may be swapped in what conditions?

[Vadim]

Of course you can replace this component (voltage regulator) on the compatible. For example: IRU1239SC and TLE4417

[dmarques]

Maybe I didn't explain myself well.

What I'm asking is how do you detect that it's damaged and needs replacement?

Thanks.

[Vadim]

OK, I understand
It is necessary to use multimeter for measure of voltage on every pin (1-7) of voltage regulator. Compare that with this diagram (see picture and table below).