Toshiba satellite A200

[bluestone]

Hi fellas,
A customer brought a faulty laptop to my shop last week, it was toshiba saltellite A200 and it wont power on nor charge battery no led indicators when you press power button but after some few troubleshooting i realize there was a short on the mobo. i later on found a MOSFET 4800B which was the problem so i removed it and replaced it with a similar one and everything start working fine, led indicators were on, battery was charging well but i found another problem i cant get a clue to, "when i press the power button there is no display and the the power keeps on restarting after every 10secs and will go off automatically on the third restart, some few months ago i had the same problem with Toshiba satellite M200 after changing a bad cap. can someone help me on this?

[Francisco.s]

Re: Toshiba satellite A200

Hi, have you checked if the MOSFET 4800B goes abnormal temperature?

[bluestone]

Re: Toshiba satellite A200

Not really but i have changed it for about 3 times over and over and i get the same results, i will check the temperature and get back to you, anyone again got any ideas? i'm ready to listen.........

[ben7]

Re: Toshiba satellite A200

Not really but i have changed it for about 3 times over and over and i get the same results, i will check the temperature and get back to you, anyone again got any ideas? i'm ready to listen.........

Ever heard of the 'NEC-TOKIN' capacitor issue? It is a filter capacitor on the CPU's VRM circuit. THe issue could also be a bad solder joint, or shorted CPU/GPU, etc..

[bluestone]

Re: Toshiba satellite A200

Yes ben7 i know about that, in fact i was part of the first people who posted that problem on this forum, and i don't think it is the issue, i have also checked for bad solder joints and replaced the CPU several times but not GPU, how ever thanks i will try all u said over again

[Francisco.s]

Re: Toshiba satellite A200

Not really but i have changed it for about 3 times over and over and i get the same results, i will check the temperature and get back to you, anyone again got any ideas? i'm ready to listen.........

It will help if you post wich motherboard is mounted. I have 3 diferents schematic motherboard for satellite A200 with many 4800B mosfets in diferent circuits.

[bluestone]

Re: Toshiba satellite A200

My mobo is toshiba satellite Pro A200, model number is PSAF4A-003007

[Francisco.s]

Re: Toshiba satellite A200

My mobo is toshiba satellite Pro A200, model number is PSAF4A-003007

Hi bluestone, this model number is not mention in any of the esquematics I have. could you see in the motherboard something like IAKAA M/B LA-3401P, or LA-3481P, or Milwaukee 10 WS2 BUILD?

[bluestone]

Re: Toshiba satellite A200

Yes francisco, i see Milwaukee 10, please help

[Francisco.s]

Re: Toshiba satellite A200

Hi bluestone, here you have the esquematic of the motherboard Milwaukee 10 WS2.
Check if it is what you need.

[bluestone]

Re: Toshiba satellite A200

Francisco Thanks a lot for the schematic diagram, but on your diagram, the 4800B mosfet has been replaced with FDS6690As but i think they are all the same but that doesn't still solve my problem. the mobo keeps on restarting when power button is pressed.

[bluestone]

Re: Toshiba satellite A200

Francisco can you please help me on how to get laptop schematic diagrams i will really appreciate it

[Francisco.s]

Re: Toshiba satellite A200

Francisco can you please help me on how to get laptop schematic diagrams i will really appreciate it

I have seen some threads in the forum about getting schematic diagrams, but I can`t remember now.
Which is the position in the schematic diagram of the mosfet?

[bluestone]

Re: Toshiba satellite A200

It is on page 8 after the U3 ic

[Francisco.s]

Re: Toshiba satellite A200

The mosfet FDS6690AS, (Q6) work in the +V1.8 circuit, and is controled by the I.C. TPS51117 (U3). Do you know if U3 is OK?.
Sometimes mosfets overload and destroy the I.C. (U3 in this case)
Please check and comment.

[bluestone]

Re: Toshiba satellite A200

I have not really checked the U3, but think I will replace it and get back to you, thanks a lot

[spidey]

Re: Toshiba satellite A200

what about the cmos battery, and also check the +3, +5, +19 etc..