Re: TECH: AppleColor RGB Sync frequencies

[dempson@actrix.gen.nz (David Empson)]

Mark C Spaeth <mspaeth@mit.edu> wrote:

> My //gs and all of its related manuals are a good 600 miles away,
> so I'll have to rely on info from all of you ;)
> 
> What is the standard sync frequency and RGB format that the GS monitor uses?

Now that I've dug out the manual...

Input signals: R/G/B video signals composited with negative going sync
1.0 +/- .5 volts peak to peak, internally terminated with 75 ohm
resistors.  Composite sync negative going 4.0 +/- 1.0 volts peak to
peak, internally terminated with 2000 ohm resistor.

Scanning frequencies for NTSC/60: 15.734 kHz horizontal, 60 Hz vertical.
Scanning frequencies for NTSC/50 or PAL/50: 15.659 kHz horizontal, 50 Hz
vertical.

(The other specs are boring details such as dimensions, bandwidth,
resolution, control positions, power consumption, etc.)

In case you can't decipher the input signal spec, it is Analog RGB.

The relevant pins on the connector are:

1  Red video ground
2  Red composite video
3  Composite sync
5  Green composite video
6  Green video ground
9  Blue composite video
13 Blue video ground

The shell is shield ground.  None of the other pins are used on the
monitor, though the IIgs does output signals on some of them (e.g. some
voltages and audio).

> Can anyone confirm these specs for either the //gs monitor or some of the
> old macintrash displays?  Better yet, has anyone tried this?  (I'd hate
> to blow out my // hardware testing a centipede board ;)

All the old Macintosh external monitors run at 30 kHz or higher.  I have
no idea what the specs are for the internal monitors in the Mac 128
through SE/30 and Classic series.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand