Picasso IV NTSC screenmodes not working

[amiga2000]

My Picasso4 is working fine (as far as I can tell) for all the rtg modes, but the ntsc and pal native amiga modes no longer work - I get a blank black screen. If I have a boot problem (like invalidated partition), it is difficult for me tostart up the computer since I cannot see the screen.
What are the possible causes for this, both hardware and software? I assume it is something involved with the picasso since if I connect a cable to the b/w video out, I can see the ntsc screen.

I was also wondering - if it turns out that the p4 hardware is broken, what are my options for getting the ntsc screenmodes to work, without messing up the p4 rtg setup -- is there some scandoubler/flickerfixer that I could use WITH the picasso4?

Thanks.

[amiga2000]

Hi - thanks for all the suggestions. I have tried pushing any chips on the P4 firmly back on the card, and the flickerfixer/scandoubler was installed separately into the video slot a while back.

I know that the motherboard graphics are working, because if I plug the b/w video out to a vcr, I can see the ntsc screenmode.

I will try re-seating the flickerfixer/scandoubler and see if that helps. I guess it is either broken, or the video slot is broken... or maybe the cables connecting the main p4 to the ffsd are broken.

In any case - I hardly use the ntsc screenmodes. I forget though - does the PicassoIV *need* that module in order to function with the rtg screenmodes? I do not think I would bother buying one, but could I install the Bio-Con Video Magician and get the NTSC screenmodes to output through that (it installs in the video slot)?

Thanks.