screen flickers

[blaze3927]

hi
basically my screen flickers on my portable ps1 prototype. the screen flickers whenever i try to run a cd/ the cd spindle is running . Y? i have no idea. one other interesting thing tho is. sometimes the screen goes really white as if there is a faint signal, this problem is fixed when i jiggle one of the aa batteries in the 8.4v battery pack tho. I am using a 2.5" rear car view monitor i got on ebay.
heres how my scph 9002 ps1 is wired.

8.4v power + goes to screen directly and another wire gose to a switch witch goes to the ps1 board

8.4v power - goes to ps1 board

the screen gets its - from the v ground on the ps1 mainboard

any help would be much appreciated

edit: stuff it i'll just buy the newer/easier psone