Thread: Composite video to VGA converters to solve dead monitor problem

Has anyone ever tried a composite video to VGA converter to solve the dead monitor problem?

My theory is you could make use of all those 640x480 obsolete computer screens we all have kicking around if these converters would work on the composite signal being fed to these old CNC monitors. You can get these converters for as little as $65 ( http://www.svideo.com/video2vga.html )

Could be a market for a cheap little gadget if these current ones don't work.

Thanks,
Dale Kramer

Many of the CNC CRT screens were/are not so much composite, but TTL EGA low freq. sysnc. I have used a few of the old TTL monitors this way on Mazaks & Fanuc's etc, if you can still get hold of them.
There were a few models that worked excellently. Unfortunately I did not pick up more of them, when they were going for about $10.00 each.
M.

The signal going to my dead monitor looks composite.

60hz repetiton, about 1.5 volt p-p signals. Definitely not TTL. I can even tell there is something flashing on my screen after I do a reference by looking at the signal on a scope.

Wish I knew what video standard they used and where I could find the info on the timings for it.

Dale

On the offhand chance you never visit the General Forum here at PM, below is the link to the thread I recently started about isolating RGBH&V wires, determining frequency and using a current model color LCD monitor on a 1989 vintage CNC control. Not exactly your situation if composite signal (mine was outputing EGA signal at 25.6 kHz on horizontal) but might be some ideas in there somewhere.

I assume if composite you only have one signal wire and one ground wire, correct ? Monochrome ?

My little "composite" story- I had an antique 1987 vintage HP workstation running a Mitutoyo CMM that output composite. The monitor went bad, and damned if it didn't turn out HP had configured that joker for some wierd frequency such that NO other composite monochrome or color monitors would work with it...I HAD to have another monochrome HP monitor of the vintage. Well, guess what they cost ? $850 to $1,200 !!!!! for a USED 12 inch monochrome monitor !!!! Probably thousands of them thrown in the trash over the years or sold at flea markets for $5, but to my amazement, after following eBay for 5 months looking for one, not a single one ever turned up there.

After much research found out HP did offer a color graphics card for that old workstation when it was new (for something like $3,000 just for the card !!!!) that output standard EGA. I found one of those on eBay or somewhere for 50 bucks, installed it. Still had to find a color monitor with seperate R, B, and G connectors...found a flatscreen like that on eBay, hooked it up and it worked ! The software displays in different colors too. [img]smile.gif[/img]

From what I read about converting a composite without getting another graphics card, it can be done but end results are likely to be "fuzzy" looking on the screen unfortunately. But hell, don't take my word for it...if I took the word of most reponders to that thread I would have given up on the LCD project, as they deemed it "impossible" to do, but it wasn't.

Converting control CRT to LCD

Thanks D. Thomas,

Sounds like you had had a lot more tries at this than I have.

Your thread is interesting, I am following it now.

I have found some specs on the monitor the composite signal goes to (yes signal and ground).

Monochrome (amber)
Scanning: non-interlaced
Horizontal freq is 20-21 khz
Vertical freq is 60hz
Video response: to 22mhz
Resolution: 384x304

If I had a 20mhz capture card I could capture the stream, analyse it and display the image on any computer (which I have a few of). Might only be able to update a few times a second though. Bit expensive though for the card.

I still have to believe there is some sort of converter for me out there.

Dale

Kilo, if you end up deciding you want to just get the original CRT fixed, these guys are good-

http://vdmservice.home.att.net

Having said that, I'm curious what your actual goal is here. Do you just want a working monitor again or are you hoping that if you can figure out a way to convert to small color VGA monitor the text will appear in color instead of that antique looking amber stuff ?

What is the physical size of your monitor CRT ?

1. I just have this aversion to paying so much for another monitor that will crap out again sometime (I know, way in the future).

2. If I do come up with an inexpensive solution, it may help out others too.

3. It is a challenge.

4. Its fun.

Its a 9", and color not a factor, in fact Amber is kinda cool, don't know what I'll get on a conversion.

I can get new 8.4" LCD's with VGA input for about $80 (delivered) on ebay, that would be nice!

Waiting for responses from 2 composite to VGA manufacturers to see if they can convert my signal.

Now, I just found out that the Hurco MHP20 I got for $900 from the same place I got my Tree 325 for $660 may have a Dyna 10 control, with the same monitor. I'm making the trip now to retrieve it. I'll use that monitor for now until I come up with a solution for the Trees monitor.

I also found a lead on getting a flyback transformer which is what I think crapped out.

Now I have options.

Will report back with my findings.

Thanks,
Dale

OK. New flyback might fix it but I replaced a confirmed* bad flyback on a Mazak color monitor once and that still wasn't enough...damn thing had other issues as well. Cost me another 300 bucks to get that one fixed.


* melted !!

Are you looking for a simple 9" crt?
I needed one for my Bosto a few years back..
Dealers wanted from $600 used to $1500 new !!!
I found one from a surplus dealer, new, in the box... for $17
I need to search alt.machines.cnc to find the address. No time right now. You can search, though.

Pete

Pete, I searched for 1/2 hr on alt.machines.cnc with no luck. If its quick and easy for you to find, please do.

Thanks,
Dale

Wow, my Hurco monitor was exactly the same and it works!

Now the time pressure is off a little for the solution to appear as I wasn't going to get the Hurco running for a few months anyway and I will be able to confirm exactly if the flyback is gone now that I have a working monitor.

I can get a flyback for $50 from www.cmbcomponents.com

OK, a little time now...
I did a search with "Bostomatic monitor" and got it. Here is a link for some monitors.
Pete


Timeline Surplus web page

Wow, my Hurco monitor was exactly the same and it works!

Well shoot, I thought you might add to our knowledge base here by trying out one of those composite to VGA converter contraptions !

Not done D.

Just have some time now to really look into this and try out some things I was talking about.

No response yet from Composite to VGA people yet. I will not forget about this.

Dale

Well, I got a reply from the VideoView distributor that said no it would not work, it outputs only VGA.

That told me he did not understand the question.

I then contacted the manufacturer in Taiwan and they said it would work.

So I bought a $58 VideoView.

It does not work. I guess the unit is not smart enough to decode different refresh rates/resolutions automatically.

Oh well

Dale

A while back I spent alot of effort looking into the whole deal of converting not composite video, but low refresh rate monitors such as Fanuc and Mitsubishi(Mazak) etc, to LCD display, these monitors have a 25khz horizontal sweep.
I looked into everything from conversion IC's, PicProcessors to Manufacturers products.
The only thing I came up with ready made was one manufacturer offered to produce one for $1,200.00+.
There were a few that offered VGA to EGA converters but claimed what I wanted would not work with their product.
I started on a conversion design, but had to shelve it due to work load.
If things let up I may resurrect it as there is still quite a few Fanuc 0's 10/11's etc out there.
What I thought would be a simple thing to solve did not turn out that way.
M.

This one is going on the back burner for me too now.

Any comments on making a little signal converter to change the voltage levels to TTL, reading it on a serial or parallel wire, and then displaying it with software conversion. Update rate doesn't have to be 60 hz, couple times a second would work. Would you lose the 60hz trigger or other triggers on TTL conversion? Heck, a 1ghz processor should be able to convert a 22mhz signal. Don't mind using my laptop at the machine every time I use it, its there anyway to transfer my gcode.

Dale

A while back I spent alot of effort looking into the whole deal of converting not composite video, but low refresh rate monitors such as Fanuc and Mitsubishi(Mazak) etc, to LCD display, these monitors have a 25khz horizontal sweep.
I looked into everything from conversion IC's, PicProcessors to Manufacturers products.
The only thing I came up with ready made was one manufacturer offered to produce one for $1,200.00+.

Did you not read my thread about just this very subject ? I did it with 24kHz ViewSonic LCD and it worked fine but the catch is the smallest ViewSonic makes with low horiz frequency is 17 inch. A company in Australia will furnish a 15 inch for $395 plus $80 UPS shipping to USA. I am going to order one to try but haven't got around to it yet. The owner tells me he's working on a 10 to 12 inch next, which would be of interest for Fanucs and such.

Dale, I'm not talking to you, I'm talking to minder. Slow down, smell the roses and read the posts more carefully

My foot in my mouth doesn't taste so good!

Been a long day, sorry.

Dale