Sync on Green RGB video
marco at familie-rauhut.eu
Sun Nov 19 03:32:23 CST 2017
I have the same problem with a cheap 19" LCD VGA Screen. What i made is
to seperate the required sync signal with an LM1881 Video Sync
Seperator. I used the standard application from the TI datasheet.The
only difference is that i used an viariable resistor on pin 6 to adjust
to the Sync Frequency. That is running with my Vax Station 4000 / 60.
Am 19.11.2017 um 04:57 schrieb Douglas Taylor via cctech:
> On 11/18/2017 6:44 PM, william degnan wrote:
>> On Nov 18, 2017 4:09 PM, "Douglas Taylor via cctech"
>> <cctech at classiccmp.org <mailto:cctech at classiccmp.org>> wrote:
>> > I have a couple of vaxes that output 'unique' video, Alpha 3000
>> 300, Alpha 3000 400, Vax 4000 VLC, and Vax Station 3100 M76.
>> > The Alpha and VLC each have a 3W3 type of connector and the 3100
>> has a 15 pin DEC designed connector.
>> > What does it take to connect these to inexpensive, modern VGA light
>> weight monitors?
>> > Doug
>> I have played around with that problem. If you have a converter to
>> get into a VGA port a newer high-end vga display will be able to
>> adjust, but not a cheap one. Because I use my vice vga/digital
>> display for mode stuff, I use a huge SGI color display for all of my
>> 3w3 outputting systems and I just switch the cable around. If you
>> could imagine 5 or 6 systems clustered around the one display.
>> I am sure someone here has a technical explanation, but in a nutshell
>> the 3W3 world signal isn't the same as a standard vga and cheap vga
>> displays can't handle the refresh rate. Someone will prob. refine my
>> answer but that's why you can't just stick an adapter on there.
>> Bill Degnan
>> twitter: billdeg
>> vintagecomputer.net <http://vintagecomputer.net>
> I ran into a similar comment somewhere on the internet somewhere (it's
> a big place) that you had to make sure that the LCD monitor supported
> the H,V rates put out by the DEC video frame buffer.
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