Thanks "Thinkpad User", who sent me T42 planar schematic by e-mail and RealBlackStuff posted picture (seen before in this tread)! I will try to resolve this problem :>

Thanks for Your answer! More powerful in this case means more current (A) resistant. But yes, You may be are right:) Could You suggest, where to find as possible detatailed T42 charging circuit schema for easiest way to find short?

When I removed chip at all, power was 16V and laptop starts. Any ideas, where to dig? Can You confirm, that original chip is FDS6990?

I changed FDS6990 with alternative (more powerful) F7832 and now it is impossible to start laptop at all. http://content22-foto.inbox.lv/albums183455246/piepz/viskas/F7832.jpg When power from 16V adapter is supplied, oscillator shows short (small part of second) and regular (cycle is about 1 sec) po...

I got T42 with problem, described in subj. Here is the picture after taking a look on mainboard: http://content6-foto.inbox.lv/albums183244041/piepz/viskas/t42.jpg Can You help me with information, what is written on chip (marked as Q4), I will try to change it myself. And how do You think, will it ...