If I use an LM1881 IC to strip the H and V sync off of an EIA RS170 sync on green video signal (NTSC?), could I then apply the RGB video lines and sync signals to a standard LCD or VGA computer monitor?
The RGB video signals are 0.7V analogue, 16kHz Horiz, 720 x 540 dots/lines resolution.
The other problem is finding a source of 12 to 13" Monitors, Google has turned up a few overseas but none in Aus.
Also looking at 15" and 17" monitor specs I notice they have a minimum
30kHz horizontal scan, where as my signal is 15kHz. Any ideas?
I don't think you'll find any multisync monitors made in the last ten years that go down to 15kHz, except those already designed for TV use.
MrT.
Is used gear ok? how about an 80's analog computer monitor (eg commodore 1084). Shouldn't be hard to find one on ebay.
If you don't mind a not-so-perfect image you could simply use a TV as a monitor, just find one with a SCART socket. The only problem I can see here is that TVs with SCART don't usualy come any smaller than
19". Though I've noticed that some small TVs (esp from sharp, samsung and lg) use a signal processing IC designed to accommodate a SCART connector, so modifying the TV for an RGB input is trivial (3 terminating resistors and 3 coupling caps).
TOO SLOW for a standard VGA CRT ! The CRT's expect at least 50Hz vertical and 30kHz horizontal.
So you are hitting it with 16kHz and 30Hz..
Perhaps an LCD can do it - they often have tuner attachements optional.
yeah its hard to find a small CRT.
easy to find small TV's, what are you doing ?? why not convert current signal to Composite ??
Thanks for the replies, I did a bit of Googling and the info on trying to get old video arcade games to connect to TVs and monitors is pretty much what you have covered.
It's a replacement for a few very old process control monitors on a ship. The sensors and processing are ok but the monitors are unserviceable. Apparently replacements were not available.
But I have found a company in the UK that make exactly what I'm after (
If they are too expensive I'll try RGB -> composite conversion using something like the Motorola MC1377 and send it to an LCD or CRT TV monitor and see what the quality is like.
Fred Ferd wrote: ...
Yeah it looks like that's what I'll have to do. See my post above.
yeah, well for a small computer accurate display you can always try australian electronics catalogues like "farnell" for "price".
they'll have small CRT's of some sort.
TV's look a bit unprofesional, with their tuning buttons and speakers..
buy a modern TV, with no buttons other than on/off. Just dont lose the remote control :)
Cheers Terry
the mc1377s are pretty crappy...there was one of them in my old amiga modulator - 80 col text was unreadable
maybe the newer encoder chips are better... if you could live without colour you could just sum the red, green, blue and sync with a fast op-amp to make monochrome composite
Give the TV/SCART modification a try - it's a bit easier that building a CVBS encoder circuit. All the LG tvs have a spot for a SCART socket (I just had a look through my archive of LG circuits and they all have this) on the PCB (under the AV sockets). It's simply a matter of removing the AV socket block, putting in a scart socket, installing the missing termination resistors and a few wire links.
I'm pretty sure the samsung ones are like this too but i've got no circuits for 14" samsung tvs so I can't be certain.
pulling pin 8 of the scart to 12v and pin 16 to 2v will force the TV into RGB mode and act as a monitor. The Sync goes into the video input
- 0.3vp-p/75R.
What about getting a US NTSC lcd display ? Lots of industrial types.
Earthlcd.com carries lot but will rip you big time on shipping (plus java based website) They have 11.3 and 12.1 inch lcds
Will need to get power supplies as well May need to get a mositure proof casing
Going to be pricey unless you can buy second hand.
Alex
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