Conference hydra::amiga_v1

4062.0. "MITSUBISHI & A2000, HELP!." by HAMER::DRAGOMIRESCU () Wed Aug 29 1990 13:21

  Could someone check my problem and help with the right advice or
suggestion?
  I try to att. a Mitsubishi multisync monitor to my A2000 with a
home made cable, and I have these strange results:

  With the cable connected to the monitor when I power up the A2000
I get first the gray and dark green and next no picture, looks dead !
I reset (AA,contr), no help, no picture.
 If I power up with no cable connected to monitor wait few sec. and
next I connect the cable to monitor input port I get the right picture
and I am back in business.
 Now  if reset (with cable connected),. I lose the picture but if I
reset without the video cable connected and plug it back few sec.late
I get the right picture back !
The cable connection is the follow:

    A2000 pin                Mitsubishi pin
    3 ana red----------------2 ana red
    4  ,  green--------------4  ,  green
    5  ,  blue--------------14  ,  blue
   11 hsync  ---------------16 hsync
   12 vsync  ---------------17 vsyn
   16-20 gnd.---------------3,5,15,1 gnd.

 Is anything that I am missing in the cable connect? Is my monitor not
sending or receiving the right signal.?
I am using the same monitor with an IBM VGA on the RGB TTL port with no
problem, is the RGB Analog port faulty?
 I will appreciate any suggestion, I looked throw notes and I did not see
any info. for this problem.

 Thank you.


  
      

The problem you are seeing is related to the diamondscan loading of the 
synch lines. This makes the Amiga "think" there is a genlock attached and
supplying clock/synch... 

Redmond cables makes a cable that uses a buffer chip to prevent this. 

Another approach I have heard, but not tried, is to use composite synch.
I do not know the details of this off the top of my head.  Perhaps another
noter has the DB23 pinouts handy.

The diamondscan is a great monitor - very versatile - for the amiga. The 
numerous input formats make it ideal for multimedia use.

	-SES

    I sorry that I don't have the time to properly answer this question
    now.  But, when I made my cable for a NEC Multi-sync 2, I think that I
    used the composite sync pin and NOT the separate H and V sync(s).
    
    		Good Luck.
    

    I made my cable up a little over a year ago so I can't remember exact
    details but I'm sure I used the composite sync signal.
    
    Shaun.