INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Composite to VGA adapter

Composite to VGA adapter

(OP)
I've spent 2 hours looking on the web for a composite to VGA adapter.
There are lots of them. I actually bought a nice one with a resolution button on it.
Unfortunately they all seem to only work with about 640x480 or higher composite signal.

I have a bunch of machine tools that have this same monitor and it's reaching end-of-life and I'd like to switch them to cheap LCD displays.

The existing monitor has these specs:



The issue seems to be the 384 x 304 resolution being pretty dang low. Additionally the monitors are all monochrome and it seems everyone selling adapters is thinking VGA => Color.

Any ideas out there?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Composite to VGA adapter

Perhaps you drilling too far down. The generic frame grabber doesn't much worry about low input resolution. Maybe something like https://www.amazon.com/Elgato-Video-Capture-analog... ?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Composite to VGA adapter

(OP)
Thanks IR. That is one way I was thinking of skinning-the-cat.

That one looks good but:

Quote:

- Video resolution: 640×480 (4:3) or 640×360 (16:9).
makes me hesitate.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Composite to VGA adapter

But, isn't that really on the other end, i.e., you'll be oversampling the composite video at ~2x to generate the VGA, but that shouldn't hurt anything.

Am I understanding that correctly? You've got something that outputs 384x304 that matches the existing monitor. So, you can digitize that same video at 640x480, and you'd wind up possibly with a letterbox display format and some aliasing on the horizontal. If you get a full-blown frame grabber, it could digitize at 384x304 and then upsample to get to VGA by interpolation.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Composite to VGA adapter

As hinted above, rather than referring to the specs for the obsolete monitor, refer to the spec for the video output signal itself. For example, 'RS-170 Monochrome' or whatever it is.

An old video standard (monochrome composite) probably would use 'Lines' of resolution instead of pixels.

Good luck.

RE: Composite to VGA adapter

That's a pretty low res (called CIF+)... my old ZX Spectrum could run at that res (think I paid less than $100 for it, a thermal printer, memory pack, and various other bits). You may find some more info with those keywords and composite video thrown in for good measure.

If you just want a replacement monitor, try here:
http://www.omnivisionusa.com/monitors/replacement-...

If you want to go LCD, you may find some useful info here:
http://www.practicalmachinist.com/vb/cnc-machining...

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Composite to VGA adapter

(OP)
Thanks all. VE1; The RS-170 didn't help much in searching.

Thanks Dan, the CIF+ was a new one to me. Interesting! Seems there's several security oriented Digital Video Recorders that will accept CIF+ video streams and could probably be forced into 'monitoring' mode where they just pass the CIF+ onto the system display screen which would be a modern display of some sort. DVI or VGA.

I've already excavated that Practical Machinist thread. Thanks.

In messing with the monitor I'd proved to myself that the kine flyback supply was dead. Removing the high voltage CRT lead and setting it up with a tiny arc path, it put out nothing at all. I'd scoped the video out of the controller and it looked like classic Composite with the negative blanking pulses and everything. The composite was interesting since this display is strictly one bit there was no continuous variation just a comb-looking field where it was peaked for an ON pixel and zero for an OFF pixel, looking about like you'd expect for a screen covered with text.

So I knew the video was good.

In desperation I tore the single monitor control board out and in the process discovered a classic evaporated solder joint on a male soldered-in pin on the cable going to the flyback. I scraped the solder resist off the trace and scraped the lead shiny on the pin and hit it with good ol Rosin 44. Soldering the pin solidly to about 10 sq mm of trace instead the original minimum solder to just the edge of a corner of the trace.

I fed the monitor 12VDC. I didn't have that whacked-out CIF+ video source at my office but was happy to see amber raster. I took it back to the machine shop and installed it. It worked! It actually looked pretty dang sharp too. The guy was ecstatic and the crisis has receded for the moment.

Keith Cress
kcress - http://www.flaminsystems.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close