mv1fz white screen

hello
i have another board with some problems
it is a mv1fz,the first time i resolve a click of death with garbage screen.it is a bad 74hc259,so replace it and now i have a white screen only.i replace with new 74hc32 ,new nec d4990 ,new 68k but the same thing
i check level state of 74hc32,i found with probe sonde

1 H 14vcc
2 L 13H
3 H 12H
4 H 11 H
5 H 10H
6 H 9H
7 GND 8H

there is activity on sp1 eprom, rams ,i will check another day with oscilloscope

so do you have an idea about this problem?
thanks for your help

check the crystals.
BB

hello big bear
i change with new crystals but same thing,problem not resolve
always white screen

I encountered a white screen today when working on a 4 slot board. I had turned it on while the upper (slow) VRAM chip was removed. Perhaps verify the OE pin on your VRAMs are pulsing.

next week,i will check all rams
thanks

hello
i check all RAMS to this board,there are all right
anybody have a way to solve it