Operating instructions

2.4.2 NR Remote Connector
When using Noise Reduction equipment, it can be automatically or remotely
switched by means of a 50-pin Amp. connector on the MTR-90III (mates with
AMPHENOL 57 series 50p plug or equivalent). See Table 2-5 for pin
assignment of this logic connector. Relay contacts only are provided. No
positive, negative or ground logic conditions are connected to these relay
contacts. One pair of relay contacts per channel is provided, and they close
(make contact) when the channel is in Input mode. The contacts are rated at
24 volts DC, 50 milliamperes.
Table 2-5
NR Remote Connector Pin Assignments
CHANNEL PIN NUMBERS CHANNEL PIN NUMBERS
1 1&26 13 13&38
2 2 & 27 14 14 & 39
3 3 & 28 15 15 & 40
4 4 & 29 16 16 & 41
5 5 & 30 17 17 & 42
6 6 & 31 18 18 & 43
7 7 & 32 19 19 & 44
8 8 & 33 20 20 & 45
9 9 & 34 21 21 & 46
10 10 & 35 22 22 & 47
11 11 & 36 23 23 & 48
12 12 & 37 24 24 & 49
NC 25 & 50
2.4.3 EXT CLOCK Connector
When the MTR-90III SPEED MODE switch is set to EXT position, the capstan
motor speed is capable of being controlled by an external reference signal.
The signal is applied via the External Clock connector on the rear of the
machine. Specifically, the external clock reference frequency is 9,600 Hz
(nominal value for the set 15 ips or 30 ips speed selected). The reference
signal should be at TTL level with a 50% duty cycle (i.e., a square wave that
is 0 volts when off, +5 volts when on). Refer to §4.2.11 for further details.
❑ Jumper Switches on the EXT CONNECTION PCB Assembly
The Jumper Switches on the EXT CONNECTION PCB Assembly must be set
before use. To access the EXT CONNECTION PCB Assembly:
1. Remove the rear connector panel by removing the four securing screws.
2. Remove the bracket with the EXT CONNECTION PCB Assembly (on the
left side of the case) by loosening the four M4 screws.
Table 2-6
Jumper Switch Settings on EXT CONNECTION PCA
Jumper Position Description
J1 (5V Current) 1-2 (=150 mA) * The 5V supply current from Pin 20 of the EXT CLOCK connector is output at
150 mA for use with the Otari Standard Parallel I/O Connector.
2-3 (>150 mA) For use with Custom Controllers requiring a signal greater than 150 mA.
J2 (Tape Speed Tally) 1-2 (30/15 ips) * Selects tape speed tallies on the Parallel I/O Connector (high speed version)
2-3 (15/7.5 ips) Selects tape speed tallies on the Parallel I/O Connector (low speed version)
J3–J5 (Fast Speed Ref) J3-J4 (EXT CLOCK) The EXT CLOCK becomes the source for the capstan control clock.
1
J4-J5 (Parallel I/O) * The Parallel I/O becomes the source for the capstan control clock.
1
* Factory default settings
1
Use either the EXT CLOCK connector or the Parallel I/O connector as the source for the capstan control clock. Do not attempt
to enter signals from both the EXT CLOCK and Parallel I/O connectors at the same time.
MTR-90III Operation and Maintenance Manual
October 1990
Section 2 Installation
2 - 11