Help! msx2 8245 weird Problems....Drive controller not work

Hi, I hope someone can help me to fix this weird acting 8245...
The msx sometime hang at startup with blue screen but with audio ok....When start good disk drive (is good) answer disk off line at files request...If i try to format always answer bad parameter error.... I tried with a pc floppy with a working adaptor and is the same....The previous owner socketed VDP Z80 ROM RAMS and Disk controller... I resoldered custom chips but the weird problems remain....The Disk drive IC controller is new...Rams are news....Could be some problems related to VDP connections??