CRT monitor gurus- 32 kHz vertical possible ??

Milacron · May 24, 2008

Looking at replacing a (1993 vintage) 14 inch color monitor on a CNC lathe with LCD if possible. As per usual with these sorts of things the R,B,G and H,V connector is not standard DB15 (in this case DB9), but according to my Hz meter horizontal seems to be 30.5 kHz but vertical is only 32 kHz ! Is this possible it could be that low ? (normal vertical is 60 kHz)

The other curiosity is, if I reverse negative and positive meter wires, so that positive is on the ground pin and negative on the vertical pin, the vertical reads 52 kHz !

If you're wondering if the meter is no good, it's always read spot on in the past when pin outputs compared with known kHz values.

Tempting to think there is something wrong with the video board rather than the monitor, but the current CRT monitor works fine for about 15 minutes but then the slightest vibration (near the monitor, not the board...board is on the backside of the machine) will shut it down....or light tap on the flyback....so almost certainly the problem is with the monitor, not the board.

Anyhoo, if it really is only 32 kHz vertical, then I'm SOL on the LCD conversion...but just hard to believe anyone made one with that low a vertical kHz as late as 1993.

Perry Harrington · May 24, 2008

The vertical refresh is 60Hz, the horizontal scan frequency is 31.5Khz. The website converters.tv sells LCD industrial panels with a 15.768Khz/31.5Khz scan frequency. Your monitor is a standard frequency, so a VGA monitor should work. The VGA standard was 31.5KHz horizontal scan, 60Hz vertical. You may be reading 30Hz because of the interlacing. The Horizontal and Vertical drives are separate pins.

You should be able to connect any vga LCD to this and get a picture.

HelicalCut · May 24, 2008

I second perry's comments with one addition that the low 30hz reading might be due to a triggering error, the vertical waveform might be a bit wonky over 2 cycles and your meter is actually triggering on every second transition giving half the usual reading.

Just to check, if you have an old 14" or similar VGA monitor lying around try it on that before forking out for a new LCD unit.

Milacron · May 24, 2008

HelicalCut said:
Just to check, if you have an old 14" or similar VGA monitor lying around try it on that before forking out for a new LCD unit.

Yep... didn't have small enough aligator clips or enough pin connectors for trial tests.... will get a female DB15 at the Shack and try again in the next few days.

Evan · May 25, 2008

Since it has a DB9 connector it's a CGA monitor. It won't work with a VGA directly.

See here:

http://pinouts.ru/Video/CGA_pinout.shtml

You need one of these:

http://www.pc-extras.com/prods/adcgav.html

HelicalCut · May 25, 2008

It would be strange to find a CGA or EGA on a 1993 machine both have TTL inputs for the RGB rather than the analogue of VGA. The horizontal scan frequency of 30.5Khz is nothing like any CGA scan frequency.

The CGA picture was so bad for displaying text I bought a monochrome monitor and adapter card at the time. EGA and CGA have very few colours (64 max)

Evan · May 25, 2008

Machine tool manufacturers are slow to make changes from designs that work. CGA is 16 colors plus 2 intensity levels for a total of 32 shades. Remember that 1993 was still Windows 3.1 time frame and 256 color VGA was normal. The scan frequencies aren't unusual as many machines using CGA would use a Hercules monochrome adapter to obtain higher resolution.

EPAIII · May 25, 2008

First, it is obvious that your vertical is 32 Hertz )Hz), not 32 Kilo Hertz (KHz). 32 KHz for a vertical scan would be questionably fast, not slow.

Second, it could actually be 32 Hz. This would likely be a progressive scan instead of the interlaced 60 Hz commonly used for NTSC TV systems.

If you are getting a replacement monitor, it would be important to know the actual scan rates and weather it is progressive or interlaced so that the replacement can be selected to match. Of course, many monitors are capable of auto detection of scan rates and adjusting to whatever is sent to them - within limits.

The TTL vs analog inputs thing is another variable, but any monitor that can accept analog inputs will work with TTLs with the proper cable/adapter. If your display is just text then this is not a great concern as shades or gray or different colors are not needed and a TTL style monitor would also work even if the original was analog.

Milacron · May 26, 2008

Sucess..... note the actual kHz and Hz figures displayed in second photo. Nice to have confirmation that pretty much any LCD monitor will work in this case....unlike my 1989 Deckel mill which had less than 28 kHz horizontal and only one LCD on the planet works with it ! (only one that is the right physical size anyway)

Note my frequency meter was only one tenth off on horizontal....or maybe the monitor is one tenth off !

HelicalCut · May 26, 2008

Nice sharp text, it looks the part it is alays satisfying to replace some oddball proprietry component with a standard one. The frequencies are standard VGA, now comes the fun of mounting it.

Milacron · May 26, 2008

HelicalCut said:
Nice sharp text, it looks the part it is alays satisfying to replace some oddball proprietry component with a standard one.

Yes, esp when the text and background are more clear and bright than the CRT was even when brand new probably....plus I can probably find a used 12 inch LCD on eBay for 50 bucks....which is a bit cheaper than outrageous prices some makes want for direct CRT replacments on CNC machines. Mazak, for example, charges something like $3,500 for a replacement monitor !

Mark McGrath · May 26, 2008

Don says.
"Mazak, for example, charges something like $3,500 for a replacement monitor !"
In the UK they are asking $9000 !

With the amount of knowledge you`ve gathered on this subject,you really need to edit it all in to a thread to save the rest of us trawling through all the posts to find it.It took me a long time to read through all the Deckel posts on the subject.
Mark.

Milacron · May 26, 2008

Mark McGrath said:
Don says.
"Mazak, for example, charges something like $3,500 for a replacement monitor !"
In the UK they are asking $9000 !

That is flat out nuts...I wonder if anyone on Earth actually buys one from them, ever ? :rolleyes5:

With the amount of knowledge you`ve gathered on this subject,you really need to edit it all in to a thread to save the rest of us trawling through all the posts to find it.It took me a long time to read through all the Deckel posts on the subject.

True...that's sort of what I had in mind with regards to personal blogs. But I suppose even better would be to categorize different subjects with links to appropriate posts..or create new posts that provide a summary of the accumulate knowledge on that subject.

mouldcugir · May 22, 2009

Maho 600C / Philips 432

Anybody knows what video standard is used and the pinouts on DB9 connector from main module or the pinouts for DB15 connector on display side

The CNC is Philips 432 with 14" color CRT

Can i use an old CGA monitor instead ?

bakerjw1 · May 22, 2009

Takes me back to the days when I did component level repair. We'd get operator heads in for Fanuc 11's where the CRTs were burned in so badly that they needed to be replaced. Replacing a color tube isn't too tough but even if they came with a yoke, we needed to used the original yoke and go about adjusting purity and setting convergence. That turned out to be quite an art form but one which I mastered.

I miss those days.

Great work Milacron!

cnctoolcat · May 22, 2009

This is a CGA monitor. Seems like it would replace the low horizontal scan cnc monitors of yesteryear, maybe??

http://cgi.ebay.com/13-CGA-Shelf-Mo...1QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

Milacron · May 22, 2009

cnctoolcat said:
This is a CGA monitor. Seems like it would replace the low horizontal scan cnc monitors of yesteryear, maybe??
http://cgi.ebay.com/13-CGA-Shelf-Mo...1QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

Most likely it would work, but the only way to know absolutely pre purchase is to measure your CNC machine's horizontal frequency signal output with a meter, and then find out the horiz freq. specs on that monitor to see how low a horiz number it will display.

Bottom line...it's all about horizontal frequency...for CNC monitor retrofit applications, size and horiz freq. are head and shoulders above all other concerns.

mouldcugir · Apr 28, 2010

Converter CGA-VGA : ACV-011

Is working beatiful also on CRT

In picture you have Maho 600 C with Philips 432 CNC connected to a 15" NEC TFT

CNC DB9 signals :

1 GND
2 Green
3
4 Vert Sync
5
6 Horiz Sync
7 Red
8
9 Blue

Also you can use the +12V line from DB9 in order to assure Power Supply for the converter (no aditional 12V 1A supply needed)

The +12V line i think it was on PIN 5 of DB9

Pictures of Philips 432 control with the adapter and TFT monitor conected :

Milacron · Apr 28, 2010

mouldcugir said:
Converter CGA-VGA : ACV-011

Is working beatiful also on CRT

In picture you have Maho 600 C with Philips 432 CNC connected to a 15" NEC TFT

For those of you that might be contemplating an LCD conversion on a control other than a Maho, I caution you that if the ACV-011 is a scan doubler, then it might not work for your application. Reason being you have to have really low horizontal frequency output for the scan doubler to work (which the Maho/Phillips does) as other wise when your horz rate is doubled you have too much horizontal frequency, which is just as bad as not enough....blank screen.

mould, looks good....but please edit your location in profile as "USA" is not good enough.

Milacron · Apr 29, 2010

Milacron said:
mould, looks good....but please edit your location in profile as "USA" is not good enough.

What the hell is "RO, Alba" ? Since the last post you've moved from the USA to Romania ?? Actually Romania would be pretty cool, but best to spell out the whole name

CRT monitor gurus- 32 kHz vertical possible ??

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