exxos's Atari, Amiga & retro forum

This is a question probably for Exxos but could be anyone who has a large amount of ST motherboards.

Is the form factor for the TV modulator same on all ST motherboards? (260ST, 520ST, 520STf, 520STfm etc.)

I can see that on later boards some of the modulator circuitry was added to the mainboard with a smaller tuner but the shape/space for the original modulator is still there (including the modulator input connector)

https://temlib.org/AtariForumWiki/index ... _revisions

What about the plastic case? Is the TV modulator output hole present on computers sold with no modulator?

Also are there any ST motherboard layouts available? e.g. either to scale 2D images or CAD design files that have the modulator footprint in?

Maybe the TV modulator board was a 3rd party design and not unique to Atari ST? Maybe a standardised footprint used in VCRs etc that I can get a datasheet on?

P.S. I know STe/MegaSTe is different.

P.P.S. I'm not looking to do anything with modulators, just to make something that goes in that space.

I'd suggest a look round here: Motherboard Revisions

I just had a quick look at it and there are definitely variations, though the area for the modulator does seem consistent, and to answer your other question, I think the modulatorless machines do have that hole filled in.