1/8th" stereo male to dual RCA female adapter for mini-
The PSone screen standardly uses an AV connection cable to connect to the PSone console. Rather than trying to convert this AV connection with an adapter for RCA, you could buy a converter for the mini-jack input. See "Back of the PS One Screen:" pictures at
http://www.vidgame.net/SONY/PSONE.htm to see where the mini-jack input is.
Quote from Amazon.com reviewer "www.marktaw.com" :
You can plug in an external input for any kind of video - TV, VCR, DVD, PS2. Here's how.
Buy a 1/8" stereo male to dual RCA female adapter. (my comment ->) You could try
http://search.ebay.com/rca-to-3-5mm-mini
Plug the yellow video out from the PS2 into the white plug of the adapter.
Plug the white left audio out from the PS2 into the red plug of the adapter.
And you're good to go. The screen should turn itself on whenever the 1/8" plug is in.
Sure you only get a mono/left signal, but if you can switch your material to mono it works. 95% of the time this should be fine. Or you can buy further adapters & combine the left & right signals.