Thanks for this Glen..
Camera is being put together
BTW, error99 was probably caused by short circuit - one of the pins (VCC? it was one of longer ones, in the middle of connector) from CF connector was pushed out of plastic frame and was wandering around inside the camera for some time.. It fell on the table when I removed the main board. I managed to repair this (I have stereo microscope and steady hand).
Now I hope that nothing was fried inside (i have a feeling the power supply circuit is below this shield.
Interestingly, there was no problem with memory card... at least not when I was playing with it.