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-
- Alternative To ATARI SC1224 Color Monitor
- For The 520ST
-
- by Dave Young and Henry Katzmarek
-
-
- An alternative to using the Atari SC1224 color monitor is now
- available. A Sony Trinitron TV/ monitor model KV-1311CR has been
- adapted for use as a 520ST monitor by the authors.
- The Sony TV has the advantage of use as a TV, an ATARI800
- monitor, a 520ST monitor and as a VCR monitor. The ATARI800 and
- the 520ST can both be connected to the Sony TV at the same time.
- The TV has an internal switch which can be used to switch between
- either computer or the TV at will. Performance of the Sony TV is
- equal to or better than the Atari monitor. Sound on the TV is
- considerably better. By using the Sony TV one unit becomes a
- video center.
- A composite cable is needed for the ATARI800. The 520ST
- requires addition of a 5 volt regulator to the Sony TV and
- construction of an interface with circuitry to adapt the computer
- to the Sony TV analog RGB input. All of the parts can be readily
- purchased except for the connector for the 520ST monitor input.
- The authors used the Atari SM124 monochrome monitor
- connector. The connector was removed from the SM124 and replaced
- with a standard DBxx-subminiature connector. A switch and
- connector were added to the interface so that both the Atari SM124
- and Sony TV could be connected to the 520ST. The switch allows
- either the SM124 or the Sony TV to be connected to the 520ST
- without unconnecting one then connecting the other. Changing
- switch position and rebooting the 520ST will make either
- functional.
- Adaption of the Sony TV for 520ST use requires a few simple
- parts and a minor modification to the Sony TV. A 5 volt regulator
- (LM7805CT) is added to the Sony TV to provide 5 volts to the
- interface circuitry. The interface adaptor circuitry consist of an
- Exclusive OR (74LS86) and a Line Driver (74S140). The circuitry
- adapts the 520ST H-sync and V-sync signals to a single Sony TV
- Composite sync input signal.
- The 5 volt regulator is added by removing the Sony TV cover.
- Eight (8) screws indicated by arrows on the TV cover must be
- removed, four(4) are behind the tube face - one on each corner of
- the tube, two (2) at the TV back at the bottom corners and two (2)
- at RGB connector panel - middle sides of the panel. After
- removing the TV cover mount the 5 volt regulator to the silver
- heat sink labeled V OUT. Mount the 5 volt regulator with a small
- nut and bolt to the out side of the heat sink facing the side of
- the TV with the 5 volt regulator tabs facing up. A hole in the
- heat sink on the side of the heat sink can be used. After the 5
- volt regulator is secured to the heat sink, bend the middle,
- ground, tab over and solder to the top edge of the heat sink. Then
- solder a wire to each of the other two tabs.
- Now connect the other end of the wires from the 5 volt
- regulator tabs to the side panel printed circuit card assembly.
- Solder the IN tab, the right tab as facing the mounted 5 volt
- regulator, wire to the +12 volt pin 1, is marked as +12 V, of
- three (3) pin connector contact B-9 or the six (6) pin connector
- contact B-6. Next solder the OUT tab, the left tab as facing the
- mounted 5 volt regulator, wire to an unused pin on the Sony TV
- analog, thirty-four (34) pin connector contact, the authors have
- used both pins 1 and 28 for the +5 volts.
- Assemble the Sony TV and you are ready to connect the
- adaptor.
- The adaptor and cable build takes the most time. Solder the
- two integrated circuits on a printed circuit card or use sockets
- for easy replacement , Radio Shack's experimenter's IC perfboard
- works. Connect pins 14 of both IC's together and pins 7 of both
- IC's together. Connect pin 3 of IC 74LS86 to pins 1,2,4 and 5 of
- IC 74S140.
- Assemble the connector removed from the Atari SM124
- Monochrome monitor to a cable of ten (10) conductors or more. Be
- sure to label the ends of the SM124 cable, wires, as to the pin
- numbers they were attached for reference when attaching a new
- connector.
- Assemble a flat cable to connect the adaptor to the Sony TV
- RGB analog contact. A standard thirty-four (34) connector flat
- cable and cable connectors available at Radio Shack can be used.
- Rebuild the SM124 Monochrome monitor cable with a new
- connector. Use the same pin numbers as were identified when the
- original connector was removed. Make sure that a mating connector
- for the new one used is available for the the adaptor assembly. A
- standard DBxx-subminiture, 25 contact connectors were used by the
- authors.
- Assemble the adaptor. Start with a box to mount the adaptor
- parts in. Radio Shack has a number of usable boxes. Mount the
- mating connectors for the Sony TV analog RGB flat cable and the
- Atari SM124 Monochrome monitor cable as desired. Mount a
- subminiture double pole, double throw (DPDT) switch with center
- OFF position, also available at Radio Shack, so it is readily
- accessible. Mounting a 5 volt LED unit to indicate Sony TV
- connection and adaptor power are available is a nice addition.
- Mount the IC printed circuit card assembly in the box.
- The internal wiring for the adaptor assembly is described in
- stages. Starting with the Atari 520ST pin connections:
-
- 520ST Adaptor
- Monitor Connection Monochrome Connector
- Pin Description Pin Description
- ___ _____________ ___ _______________
- 1 Audio out 1 Audio in
- 8 Ground 8 Ground
- 11 Monochrome 11 Monochrome
- 13 Ground 13 Ground
-
- 520ST Adaptor
- Monitor Connection Sony TV Flat Cable Connector
- Pin Description Pin Description
- ___ ____________ ___ _______________________
- 1 Audio out 24 Audio input
- 6 Green 26 Green input
- 7 Red 25 Red input
- 8 Ground 4 Ground
- 10 Blue 27 Blue input
- 13 Ground 6-16 Ground
-
- 520ST Adaptor
- Monitor Connection IC 74LS86, EXCLUSIVE-OR
- Pin Description Pin Description
- ___ _____________ ___ __________________
- 9 Horizontal sync 1 Gate 1 input
- 12 Vertical sync 2 Gate 2 input
- 13 Ground 7 Ground
-
- 520ST Adaptor
- Monitor Connection IC 74S140, LINE DRIVER
- Pin Description Pin Description
- ___ _____________ ___ _________________
- 13 Ground 7 Ground
-
- 520ST Adaptor
- Monitor Connection Subminiture DPDT Switch
- Pin Description Pin Description
- ___ ____________ ___ ___________
- 4 Monochrome detect 2 Side one center
-
- 520ST Adaptor
- Monitor Connector LED
- Pin Description Pin Description
- ___ ____________ ___ ___________
- 13 Ground 2 Cathode side
-
- Adaptor Adaptor
- IC 74LS86, EXCLUSIVE-OR IC 74S140 LINE DRIVER
- Pin Description Pin Description
- ___ ___________ ___ ___________
- 3 Gate 1 output 1,2, Gate 1 inputs
- 4&5
-
- Adaptor Adaptor
- IC 74S140 LINE DRIVER Sony TV Flat Cable Connector
- Pin Description Pin Description
- ___ ________________ ___ ___________
- 6 Gate 1 output 30 Composite sync input
-
- Adaptor Adaptor
- LED Sony TV Flat Cable Connector
- Pin Description Pin Description
- ___ __________ ___ ___________
- 1 Anode side 1 +5 volts
-
- Adaptor Adaptor
- Subminiture DPDT Switch Sony TV Flat Cable Connector
- Pin Description Pin Description
- ___ ___________ ___ ___________
- 4 Side two top 1 +5 volts
-
- Adaptor Adaptor
- Sony TV Flat Cable Conn IC 74LS86, EXCLUSIVE-OR
- Pin Description Pin Description
- ___ ___________ ___ ___________
- 1 + 5 volts 14 Vcc
-
- Adaptor Adaptor
- Sony TV Flat Cable Conn IC 74S140, LINE DRIVER
- Pin Description Pin Description
- ___ ___________ ___ __________
- 1 +5 volts 14 Vcc
-
- Adaptor Adaptor
- Subminiture DPDT Switch Sony TV Flat Cable Connector
- Pin Description Pin Description
- ___ ___________ ___ __________
- 5 Side two center 29, Fast blanking input
- 33, RGB/NORMAL mode select
- &34 Audio select
-
- Adaptor Adaptor
- Subminiture DPDT Switch Monochrome Connector
- Pin Description Pin Description
- ___ ___________ ___ ___________
- 3 Side one bottom 4 Monochrome detect
-
- If you are interested in more details, or wish to have a Sony
- TV converted for your Atari 520ST contact the authors. Note that
- installation of the 5 volt regulator may void your Sony TV
- warranties.
-