toshiba U400/M300/ cannot get 3,3 an 5V

[ktmmotocross]

Hello.
Have this one with bad ICH. replace it but cannot get 3,3V and 5V from ISL6237. No short on rails, powers to chip looks good, EN1/EN2 ok, even REF signals is there. but cannot get it to start. I replace ic fron another board but still the same results

Any help for this?

[dj_ricoh]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

find RTCRST# on kbc and post values before and after pressing power bt

and RSMRST

[ktmmotocross]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

find RTCRST# on kbc and post values before and after pressing power bt

and RSMRST

I think u need a sleep for this day

no 3,3V = no power to anything. no power to switch, no power to KBC

[meritosari]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

on pin 11 fb1 voltage?

[dj_ricoh]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

any fets broken?

how many volts you got on rtc battery?

the rtc makes VCCRTC so thats you first pass the it goes to normal after you plug the charger.

it disable the rtc and makes the vcc from adapter so maybe maybe

[meritosari]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

i just read case on SN0608098RHBR losing voltage on vfb1 causing 3.3valw/5valw can't come out, maybe its a culprit.

look like its similiar pin

[ktmmotocross]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

here u have all voltages in ISL6237

[rievax_60]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

You need to check the 3.3v and 5v SMPS rails with a DSO when power is first applied. The rails could be coming up then soon after going down because of some protection trip.
I had something once where the 5v rail was getting up to 6v, then back to 0v because of a leaking high side MOSFET. This all happens in a few milliseconds.

[ktmmotocross]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

Damn mate u have right

All voltages goes up but after 1-2 seconds goes down. I check pl9 that gives 1.05V and have 13ohm instead of 50ohm on the other board.

[Th3_uN1Qu3]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

That shouldn't be a problem. It's something else.

[ktmmotocross]

Re: toshiba U400/M300/ cannot get 3,3 an 5V

yes its that damn ICH. removed it and have stable voltages.
must find some working ic.