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8.5.1 TCI-2A Cartridge Interface
The TCI-2A Cartridge Interface (PR&E #99-165) was specifically designed for use with PR&E
TOMCAT and Micromax cart machines. Each TCI-2A can accommodate up to three reproducers or
recorder/reproducers. For a schematic of this interface, as well as a diagram of the console to interface cable
(PR&E #99-38), see Section 8.6.
NOTE: If you already have TCI-2 interfaces for TOMCAT, they may be modified slightly to work with
both TOMCAT and Micromax cart machines, as follows:
1.
Replace resistors R1, R3, R5, R7 and R9 with 750 ohm, 1/2 watt resistors (PR&E #3-751).
2.
On the component side of the PC board, cut the trace going to J4 pin 4.
3.
Add an insulated jumper wire between J4 pin 1 and the trace that previously went to J4 pin 4
(which was cut in step 2).
4.
Verify that resistor R14 is a 10M ohm, 1/4 watt resistor (PR&E #2-106).
CIRCUITRY
The TCI-2A uses opto-isolators to eliminate potential audio/logic ground loops. The LED inputs of opto-
isolators U1 thru U5 are connected to the cart machine tally outputs through current limiting resistors R1,
R3, R5, R7 and R9. The collector of opto-isolator U1 is connected to the AUDIO RESET line on console
connector J1. When the FWD LIGHT tally is present at cart connector J4, current flows through U1's LED,
turning on its output transistor, and pulling the AUDIO RESET line to console LOGIC COMMON. When
the STOP LIGHT tally is present at cart connector J4, U2 will operate in the same manner, pulling the
READY line to console LOGIC COMMON. Capacitor C2 will pulse the AUDIO RESET line low at the
"rising edge" of the STOP LIGHT tally, thus providing a console AUDIO RESET when the cart machine
stops.
Opto-isolators U3, U4 and U5 provide open collector outputs referenced to an isolated COMMON on
connector J3. These opto-isolators function in the manner described above, in conjunction with the
remaining cart tallies: PLAY LIGHT, SEC LIGHT and TER LIGHT.
NOTE: These outputs can be used to provide automatic "cart sequencing" by connecting the appropriate
cart cue line on connector J3 to the console ON input on J2 of the "next" cart machine interface. The isolated
COM on connector J3 needs to connect to LOGIC COMMON as well. If needed, a switch can be installed
in series with the connection to disable the cart sequence. The J3 outputs from several cart machines may
also be paralleled together to form an "end of message" warning bus. This bus can then be buffered, as
needed, to drive external warning lights. Contact PR&E for more information.
Opto-isolators U6 and U7 are connected through current limiting resistors R11 and R13 to the console
START and STOP pulses on J1, respectively. The open collector outputs of U6 and U7 are connected to
PACIFIC RESEARCH & ENGINEERING
209
BMX SERIES III CONSOLE
REVISION B
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