Knut wrote:
"Ed Eastman" <noone@nowhere.net> wrote in message news:dfpv83$3sd$1@unlnews.unl.edu...Well, you can't just attach the sync signal to the green, it has to be incorporated digitally.Use an 1881 to get your sync signals back...LM1881 'Video Sync Separator' seems to be a very useful ic there if I really need it.After thinking a bit more about the mitsubishi monitor from my own post:I then made a quick adapter for the mitsubishi monitor without the resistors to display "8 colors". It wasn't a success either. The picture was stable but the screen was garbeled. It seemed to me that horizotal sync wasn't working, that the lines were too long or too short. making each scanline not in sync with the next. Either there is a problem with the levels or the monitor might be broken (I will open it and see if there is anything to adjust.and rereading the Marco Orlandi's document I probably need to change the level of the sync signal. He cuts a resistor, I probably need to do that.As is I have no real documentation for the RGB card, couldn't find anything on the net either. There is the little dipswitch with two switches and a jumper. I notice that the dispswitches are differently set than Marco Orlandi have them. The jumper is open/empty. Does anyone know what these do?
Well, I'll answer that myself, what they do. The dipswitches set the color of the text (text mode characters)
off off = white off on = red on off = blue on on = green the jumper if closed set DB15 pin 15 to 5V otherwise pin 15 is unconnected.And regardless I have problems with sync. I did get hold of an LM1881 and set it up to make the vertical sync.
I tried both to supply the 1881 with 5V and 12V with no signifficant difference. I also tried the horizontal sync through the 1881, not much difference there either.
There were a slight improvement with the LM1881 generated vertical sync, now I could get the CGA monitor to sync if I put the vertical size to maximum (loosing a third of the picture). I could not get the mitsubishi to really sync at all even when I opened it and found some more controls, like vertical and horizontal hold adjustment.
Knut