What to use a 4.5" B&W TV for?

Tony Duell ard at p850ug1.demon.co.uk
Mon Mar 23 14:32:03 CDT 2009


> The issue of VGA to composite output doesn't exist. The television has one IC 
> (AN5151) which does all the IF demodulating and so on. It has a horizontal 

I've not looked at the data on that chip, but I would be suprised if 
there wasn't some hack to feed composite video in somewhere. Maybe into 
the pin where the output of the IF filter connects or something.

Of course you could make an amplitude-modulated oscillator at the IF 
frequency and feed that into the input of the chip (remove the tuner), 
but that seems like too much work :-)

I obulf a little TV a few years ago with the intention of adding a 
composite input and having it on my workbench to test home computers with 
RF output and also displaying composite video. With a 5" or so CRT it's 
limited ot 40 column text but it's still useful for testing.

I didn't do the mod in the end. Mainly becuase I noticed a pair of RCA 
phono sockets on the back, one for composite video in, the other for 
line-level audio in. They're the sort of sockets with internal NC 
switches that disconnect the output of the TV detector whrn you stick a 
plug in. Not ideal, but useable.

-tony




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