Quote:
Originally Posted by jr_tech
Has anybody here figured out a way to modify an older set to take component video? I imagine that it would be much more difficult to accomplish, but even better picture quality might be obtained. 
How about an isolated input circuit for use on "hot chassis" sets?
jr |
Well, if you find the "right" DVD player it actually isn't hard at all, for B&W sets.
By "right" I mean one that doesn't bother turning off the YBR ports when its in "composite out" mode. (Older is better, usually.) Essentially the Y (Green) outputs a standard 525 line luminance signal which on modern component inputs results in "no signal" or something not all unlike a B&W set with the horiz oscillator running at 2x normal freq. Easiest way to see if you have this type of DVD player is just whack a scope on the green jack while confirming a normal picture is coming out of the yellow or S-video connection on a normal TV set.
Just shove that signal into the appropriate point on the chassis. (You may need to rig up a phase inverter, depending on if the tuner in your chassis is positive or negative sync. YMMV.)
Edit for related ramblings:
If you're going to add a baseband input to anything B&W you should always try and feed it from an S-video jack, using only the Luma signal pin (and ground,
obviously.) Unfortunately a lot of things that have "S-video out" don't actually supply
both discrete Luma and Chroma signals, the really cheap crap just mixes them together or duplicates the composite signal on both pins. Same can be said for the really cheap stuff with an "S-video input" on it. Usually a resistor and cap combining the signals near the jack and feeding the result to the same point as the Composite jack goes. (I do miss TVs that had properly designed/engineered comb filters.) Poke an S-video jack with a 2 channel scope sometime to see what goes on. Ideally you're supposed to have pure 525 line Luma available, which is great for pre-color sets! As above you may need to add a sync inverter depending on your chassis. (Possibly bypass a built in sync inverter, as long as its before the vertical drive pickoff, otherwise you'll not get sync.)