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Substitute a standard VGA monitor for an OEM unit

I'm working on a display monitor which is used in a wheel alignment machine in a garage. The unit is a type of VGA monitor which was manufactured by Kristel Corp. It has problems and I would like to see if I can substitute a standard VGA monitor in its place. It uses a special connector which according to the schematic has the following connections:

1- Red in 2- Red ground 3- Green in 4- Green ground 5- Blue in 6- Blue ground 7- Common ground, (common with video grounds) 8- H-sync in 9- V-sync in 10- NC There is a 75 ohm resistor from each color input to ground. All grounds are common. I found a pinout for a 15 pin VGA connector. It is marked: Standard VGA monitor pinout

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1 Red Video 2 Green Video 3 Blue Video 4 Monitor ID - Bit 2 5 Ground 6 Red Ground 7 Green Ground 8 Blue Ground 9 [KEY] 10 Sync Ground 11 Monitor ID - Bit 1 12 Monitor ID - Bit 0 13 Horizontal Sync 14 Vertical Sync 15 N/C (Reserved)

I would like to try to use a standard VCA monitor for this application. Can I use the substitute monitor by connecting its RGB inputs to the alignment machine electronics RGB connections, then tie all the grounds together, and then connect the h and V sync to their appropriate pins? Do I need to worry about the other connections? The OEM monitor doesn't seem to use any of them The following is what I have in mind:

Standard VGA Oem cable from from alignment machine monitor pinout

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1 Red Video 1- Red out 2 Green Video 3- Green out 3 Blue Video 5- Blue out 4 Monitor ID - Bit 2 - N/C 5 Ground 7- Common ground 6 Red Ground 2- Red ground 7 Green Ground 4- Green ground 8 Blue Ground 6- Blue ground 9 [KEY] - N/C 10 Sync Ground - conn. all gnds together 11 Monitor ID - Bit 1 - N/C 12 Monitor ID - Bit 0 - N/C 13 Horizontal Sync 8- Hor. sync 14 Vertical Sync 9- Vert sync 15 N/C (Reserved) - N/C

I'm not sure about the Hor sweep rate but I think that its compatible. Would an old type multisync monitor. (of the type that I scrapped years ago) have been a better choice for this conversion? I also have an old RGB monitor with separate BNC connectors on the back for RGB and V and H sync. Might that also work? If anyone has some further information on this I would be very grateful. Lenny

Reply to
captainvideo462002
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On Mon, 6 Apr 2009 20:40:25 -0700 (PDT), " snipped-for-privacy@yahoo.com" put finger to keyboard and composed:

... inside the monitor and video card but not in the cable.

Keep the sync ground and RGB grounds separate. Also run separate video grounds for each RGB signal. Use mini-coax for the RGB connections.

You can measure the horizontal frequency of the wheel alignment machine at the VGA connector.

You may find its specs here:

formatting link

This monitor could be one of those fixed frequency types. I'd power it up and aim a CRO probe at the CRT. The radiated flyback pulse will tell you the free running frequency of the horizontal oscillator. One problem with fixed frequency monitors is that they usually expect negative sync whereas a VGA card can produce sync pulses of either polarity depending on the video mode.

- Franc Zabkar

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Reply to
Franc Zabkar

Not sure if this helps, but a modern LCD TV with a VGA input seems to work at pretty well any frequencies that older computers used - the ones that needed a multi-sync type.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

In message , " snipped-for-privacy@yahoo.com" writes

What is the make and model of the wheel alignment machine?

--
Clint Sharp
Reply to
Clint Sharp

working on a display monitor which is used in a wheel alignment

Its a Hunter D111

Reply to
captainvideo462002

I would check that pinout against the one for an EGA monitor !

--
Best Regards:
                     Baron.
Reply to
Baron

It should work fine as long as the horizontal frequency is at least

31.5 kHz. All modern VGA monitors, including LCDs, are "multisync", and will work with any scanning rate, and sync polarity. Fixed frequency VGA monitors haven't been common for about 15 years.

I would build an adapter cable rather than modifying a specific monitor. That way it will be easy to replace the monitor again in the future. Andy Cuffe

snipped-for-privacy@gmail.com

Reply to
Andy Cuffe

That's not my experience. Check the spec. I have an old computer which uses UK TV res for some things and all the VGA I've tried give 'out of range' on this. However, the original multisync works happily with it.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

In message , Baron writes

Or even CGA. Might be worth finding a TV with an RGB input and seeing if it syncs.

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Clint Sharp
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Clint Sharp

On Tue, 7 Apr 2009 13:10:49 -0700 (PDT), snipped-for-privacy@yahoo.com put finger to keyboard and composed:

working on a display monitor which is used in a wheel alignment

Can you upload the circuit diagram(s) for the monitor? Alternatively, do you have the part number for frequency sensitive components such as the flyback transformer, deflection yoke, oscillator chip?

- Franc Zabkar

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Reply to
Franc Zabkar

ainst the one for an EGA monitor !

I do have an old Sony commercial RGB monitor down in the basement. Looks like Columbus may have brought this one over with him. It has 5 BNC inputs, for RGB and V and H sync. I don't know if its multisync or not. Seriously though it must be at least 15 to 20 years old. I considered trying it. Lenny

Reply to
captainvideo462002

I don't know whether they are still available, but you could get a cable with 5 colour coded BNC on one end and a 9 pin cga/vga plug on the other. These monitors are usually fixed frequency, sync on green devices.

--
Best Regards:
                     Baron.
Reply to
Baron

against the one for an EGA monitor !

That is probably a fixed frequency monitor for early desktop CAD systems. I have several, and the special video cards are damn expensive.

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Reply to
Michael A. Terrell

In the UK at least many CRT computer monitors had both VGA and BNC inputs

- selectable. My last Panasonic 17" - replaced by this LCD - did.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

I should have said "any scanning rate within its range". For a normal PC monitor, that 31.5 kHz and up to its maximum (often 100kHz +). Very few VGA capable monitors can sync down to TV resolution (some early CGA/EGA/VGA multisyncs can since CGA uses TV scanning frequencies). As long as it's at least VGA, it should work with any modern monitor. Andy Cuffe

snipped-for-privacy@gmail.com

Reply to
Andy Cuffe

Yup. FWIW I have a TV with VGA input which seems to cope with a wider range than most computer monitors, at the lower end of the range.

My original Multisync used to have a relay that clunked when going from TV frequencies to more usual computer ones.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

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