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Sony KPR-4150 -- RGB Multi Input Connector



Jan 1, 1970
June 2004,
Jonathan Moore Liles

This connector is Multi because it can be switched between three
modes: Digital 1, Digital 2, and Analog.

Diagram (Female):

|1 5|
| |
|2 6|
|3 7|
|4 8|


[ Digital 1 ]

Pin Function
1 Intensity (TTL)
2 Red (TTL)
3 Green (TTL)
4 Blue (TTL)
5 Ground
6 Ground
7 Horizontal Sync (TTL)
8 Vertical Sync (TTL)

[ Digital 2 ]

Pin Function
1 n/c
2 Red (TTL)
3 Green (TTL)
4 Blue (TTL)
5 Ground
6 Ground
7 Horizontal Sync (TTL)
8 Vertical Sync (TTL)

[ Analog ]

1 n/c
2 Red (analog)
3 Green (analog)
4 Blue (analog)
5 Ground
6 Ground
7 Composite Sync (analog)
8 n/c


Each of the three modes accepts only 15.75kHz horizontal and
60Hz vertical timings. Digital 1 is suitable for CGA
sources, Digital for 2 EGA sources, and analog for VGA
sources (with appropriate sync correction).

TTL == 0-5Vp-p
Analog == 0.7Vp-p (negative)

The analog mode was apparently designed by Sony to support
the minimum required by their SMC-70 microcomputer.

Analog mode accepts only composite sync of negative polarity
and at analog voltage levels. Normal VGA cards output TTL
level sync, and only a few are capable of generating a
composite signal. Most ATI cards are equipped with this
capability, as well as having low enough minimum dotclock
settings to be able to output the necessary 15kHz signals.
The same may also be true of some older SiS cards, but I
have a collection of video cards numbering in the hundreds
and the only group that seems to work is ATI.

In order to use the signal from an ordinary VGA card one
must build an appropriate circuit to combine, invert, and
drop the voltage of the sync signal as is necessary. If your
card can output composite negative sync (as do some ATI
cards) then your job will be easy. Otherwise you may employ
some simple and widely available ICs such as the 7404 hex
inverter, the 7402 quad NOR gate, and the 7432 quad OR gate.
The circuit should consist of a power-supply (4 AA
batteries), a voltage regulator (7805), one of the ICs
listed above, and two resistors to drop the voltage from
5Vp-p to 0.7Vp-p--and of course some capacitors if you plan
to use some other DC supply instead of the batteries. The
voltage drop resistors should comprise 330 ohms between the
IC output and the output of the circuit and 100 ohms between
the output of the circuit and ground. Since video drivers
often quietly ignore your settings an oscilloscope will
probably be required to determine input sync range and

[ separate positive TTL sync -> composite negative analog sync ]

/------------| |- 5V Vcc ---------\
| +hsync -| IC | \ ------\
| +vsync -| | *------- 7805 |
| | 7 | _______ / ------/
| | 4 | ___ /
| | 0 | _ |
| *----| 2 | |
| _______ \----/ \---[+|-]
| ___ 6-20V dc
| _
| 330R
-csync ----/\/\/\----*--------- MI Pin 7
5Vp-p | 0.6Vp-p
\ 100R

More complicated circuits can be built to accept any
standard configuration of input and combine/invert as
necessary, but this seems excessive since the number of
video cards capable of generating such low horizontal
frequencies is severely limited.

For those interested, the Atari ST computer outputs TTL
level negative composite sync on pin 2 of its Monitor
connector, requiring only the voltage adaptation to be
suitable for use on the KPR-4150. The picture is simply
amazing, even more so when compared to my Commodore 1084S
12" monitor.

In fact, the quality in general of the RGB input is quite
good as used for viewing DVD/DivX material and playing
arcade games through emulation. And certainly vastly
superior to composite TV-out solutions.

I am still experimenting with video modes. I haven't had
much fortune with low-resolution progressive modes like
320x240, but the following mode is acceptable for DVD

Modeline "ntsc_720x480" 13.72 720 744 808 872 480 488 494 525
composite interlace # H 15734 [Hz], V 59.939 [Hz]

If you have anything to add, such as corrections or the
applicability of this information to other Sony models,
please do so.