[Coco] S-video Prospects...

Roger Merchberger zmerch at 30below.com
Sat Dec 17 14:15:36 EST 2005

So, according to my CoCo3 Service manual, the PAL CoCo3 motherboard does 
seem to be different than the NTSC CoCo3... but if one were to acquire a 
PAL board & change the crystals, (a la Sockmaster) one could  generate S-Video.

Also, according to the manual, the GIME chip in the NTSC & PAL CoCo3s are 
the exact same chip; so saying that chroma & luma are generated totally 
internally on the NTSC CoCo3, whilst true, seems to be also true of the PAL 
CoCo3 as well...

So if the PAL board is generating chroma & luma from RGB, and if one could 
find a source of PAL boards but with NTSC crystals, anyone in the US could 
have S-Video on their CoCo3, right?

That said, my service manual has the complete parts lists (right down to 
the capacitors & resistors) and a PCB layout of both sides of the PAL 
daughterboard. If all of the 3 chips are commercially available, other than 
the actual building of the board, one _might_ be able to come up with a 
source of PAL boards without having to destroy PAL CoCo3's in the 
process... ;-)

How much trouble would a person be in if he or she were able to... 
"replicate" the PAL board? [[ Admittedly, it's not like said person would 
be costing Tandy any lost profits... ]]

Just some random thoughts for a non-random Saturday...

Roger "Merch" Merchberger

Roger "Merch" Merchberger   | "Profile, don't speculate."
SysAdmin, Iceberg Computers |     Daniel J. Bernstein
zmerch at 30below.com          |

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