Connect with us

Toshiba p30 laptop power problem

Discussion in 'Electronic Repair' started by Lee, Dec 3, 2011.

Scroll to continue with content
  1. Lee

    Lee Guest

    Tbh I'm not really expecting any solutions other than "replace the
    mainboard" but I'll ask anyway in case someone has fixed the same problem...

    Short version:

    Toshiba P30-144 laptop.
    Mostly this thing behaves dead with no lights. Very occasionally the AC
    power and charge lights come on and then it will switch on and boot
    normally only to shut down after a few seconds and then play dead again.
    DC socket is fine, both CPU fans work and the heatsink has been cleaned.

    More details:

    From what I can see it seems to be going into some sort of protection
    mode,in this condition the 19v supply is present on the DC jack and up
    to what looks like the main voltage mosfet controller (can't read the
    numbers on it) but no volts on the mosfets themselves. (there are 4 of
    these which together provide 5v - separate from the CPU vcore ones)
    There is what seems to be a 3.3v standby voltage but no other secondary
    supplies function and the charge voltage to the battery is 1.4v.
    What makes me think it's a protection problem is because as the dc
    adapter voltage is removed there is a brief spike on the charge voltage
    up to 15v and the secondary supplies come up very briefly.

    Things I have checked by substitution - another known working CPU,
    memory, backup battery and ac adapter.
    I've also checked all the fuses and simple diodes, as well as the main
    mosfets. The supply caps are those nasty smd cans that give problems
    elsewhere but they check ok and I've tried replacing them anyway more in
    hope over expectation :)

    Given that I can't read the id on the main PWM controller, the age of
    this thing and that any factory level diagnostics is definitely BER any
    other ideas? ;) :)
     
  2. Franc Zabkar

    Franc Zabkar Guest

    I couldn't find your model, but perhaps there are similar ones
    (Toshiba NOTES)?
    http://www.4shared.com/folder/0S3W-zjF/MOBO_SCHEMATICS.html

    - Franc Zabkar
     
  3. Lee

    Lee Guest

    Many thanks for the link, the A80 looks to have some similar circuitry
    and has given me some good ideas for things to check, not least all the
    SI4800DY_SO8 this thing uses a truck load of them...

    Lee
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-