What to do? 520 STfm vs. 1040 STF

[cbmeeks]

OK, so I have an Atari 520 STfm that I *think* works.

 

I also have a couple of 1040 STF motherboards. So I thought it would be a brilliant idea to take the 520 motherboard out of its case and put the 1040 motherboard in.

 

I quickly Googled the power requirements and it looks like the built in PSU should provide enough.

 

Plus, everything physically fits perfectly.

 

Then, like a dummy, I realized that the 1040 STF does not have an RF modulator (the "m" in the 520STFM).

 

I don't have an Atari monitor. Only a few composite TV's.

 

I don't know enough about ST's to know how easy/hard it would be to make a cable for the monitor port and (perhaps?) convert the video signal to S-Video or composite.

 

Should I just try and find an expensive Atari ST monitor on eBay? Don't really like that option seeing how even composite monitors are getting harder to find.

 

Or, should I just put the 520 motherboard back in and try to get it to work?

 

I can post pics if needed.

Thanks!