Toshiba C660 voltage rail problem

[lord]

Hi all,
I have this problem, i am missing a 1.5V rail. It is a LA-6842P rev.1.0 board (page 39 of the attached schematic).
The MOSFET-s are OK, VTTP_EN is 5V, i have 5V at Low Driver Gate, but nothing on the DH (pin 13).

Could it be the chip?
Is there a posibility that anything else in the circuit could be wrong?

Regards,
Darko

[whaldsz]

Re: Toshiba C660 voltage rail problem

What do you get at pin6 PGOOD pin?

[lord]

Re: Toshiba C660 voltage rail problem

It was the chip, i replaced the stock G5603RU1U with TPS51117 and it works. Now when i have the 1.5V and all power supplys to clock generator, i don't have frequency on the crystal. :|
Suspect the clock generator now.

[lord]

Re: Toshiba C660 voltage rail problem

What do you get at pin6 PGOOD pin?

Nothing, logical low voltage.

[whaldsz]

Re: Toshiba C660 voltage rail problem

Nothing, logical low voltage.

And you get a voltage at PL802? If so, then there's something wrong with this circuit. PGOOD pin should be high. Is the +5VS and PR811 ok?

[rtstorm]

Re: Toshiba C660 voltage rail problem

what is the symptoms of this fail? (LED, fan, display)

[whaldsz]

Re: Toshiba C660 voltage rail problem

I don't exactly understand what you mean, could you clarify more about the issue you are having.

[Francisco.s]

Re: Toshiba C660 voltage rail problem

Nothing, logical low voltage.

Recheck voltages.
Could be new replaced chip is damaged.

[lord]

Re: Toshiba C660 voltage rail problem

I repaired the 1.5V rail with replaceing the IC controller, now i miss +CPU_CORE from PU13, which i replaced already.
Here are the readings from PU13:
PGOOD at pin 1 is low
CLK_EN# at pin 40 is 3.3V
VR_ON at pin 38 is 3.3V (What does this pin do?)

I also noticed that i don't have any frequency readings from clock generator on Y1. All input voltages to clock generator and CK_PWRGD/PD# is low (i think this is supposed to be low because Q37 connects this pin with ground after CLK_ENABLE# goes hi).
I tried to replace the crystal, and i have one more used RTM890, so i tried with that but lo luck. I also tried with this used RTM890 but also no luck.

Does anyboy knows which one has to work first: the +COU_CORE rail or the clock generator?