I want a genlock for my Amiga so I can do subtitle overlays on these OVA laserdiscs I keep impulsively buying.
Dragon's Heaven is the most recent acquisition.
On a semi-related note, considering building an NTSC -> RGB decoder.
I can't find a guarantee that any of the ones on ebay aren't actually digital scalers converting to VGA, and I want one that does not change the scan frequency/resolution.
Found what looks to be a complete schematic to do it, but it depends on so many parts that are no longer being made that it's going to be somewhat expensive to build. Some of the parts don't even seem to be obtainable (like the 400ns delay line coil), so I'll be having to make one with a different (and also no longer available, but at least obtainable on ebay) IC that uses an internal AD->DA conversion to implement the delay and hope it's good enough for video frequencies.
This is all because I have a nice RGB monitor, but Commodore in its infinite
wisdom cheapness decided that unlike the earlier 1080 monitor, there was no reason that the 1942 should be able to handle NTSC video.
The decoder schematic seems to be for composite only, but I bet it'd be possible to tweak it to get S-video working. Based on the TDA3330P chip.
Most of these chips were designed to drive CRT RGB neckboards (the ones that connect directly to the pins on the back of the cathode ray tube itself) directly rather than a line-level RGB signal, which also complicates matters. Even more annoyingly, it also requires both 12VDC and 5VDC power supplies.
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postimg.cc]
(IMG:[i.postimg.cc] https://i.postimg.cc/bz1Wffrv/ntsc-to-rgb.png)
Anyone know where I can get a 400ns purely analogue delay line besides out of an old broken TV set? Haven't got any of those to spare right now.
I know some genlocks have circuitry to do this built in, but those would be troublesome to adapt to use with other non-Amiga hardware.
Edit: found a nice writeup of the genlock circuitry for an Amiga 1000 genlock (A1300). [
wiki.preterhuman.net]
https://wiki.preterhuman.net/Genlock_circui...ion_descriptionThis post has been edited by dragontamer8740: Mar 8 2023, 13:37