CG2 genlock board with Iris 4D/240GTX

[Kian-Tat Lim]

	We have been attempting to connect our Iris 4D/240GTX with CG2
genlock board to an NTSC monitor.  At first, we had no success
following the information in "Using the Composite Video/Genlock
Board".  We consulted SGI, who faxed us "Set Up/Integration of the CG2
board", a 25 page document.  We were then able to produce a picture on
the monitor, but only when the SYNC output on the Iris was connected
to the external sync input of the monitor.  The picture contains
numerous spurious horizontal lines, making it unusable for our
application.

	This problem occurs in both NTSC mode [setmonitor(NTSC);] and
CG2 mode [setvideo(DE_R1, DER1_G_170 | DER1_UNBLANK);
setvideo(CG_MODE, CG2_M_MODE2);].  Every graphics-related board in the
machine has been swapped; only the CPU and IO boards have not been
changed out.

	We are still talking to SGI, but I was wondering if anyone
else has any experience with this board or with this particular problem.

-- 
Kian-Tat Lim (ktl at wagvax.caltech.edu, KTL @ CITCHEM.BITNET, GEnie: K.LIM1)