RJM ARTS-201B User manual

RJM & Associates, LLC
175 Joerschke Drive, Suite A
Grass Valley, CA 95945
Phone: [phone] Fax: [phone]
info@rjmandassociates
www.rjmandassociates.com
ARTS-201B
2 x 1 Analog Protection Switch

Statement of Warranty
Statement of WarrantyStatement of Warranty
Statement of Warranty
RJM & Associates, LLC warrants its products for a period of three (3) years from
the date of shipment to e free from defects in materials and workmanship and
meets applica le pu lished specifications. Equipment which has een operated
within its ratings and has not een su jected to mechanical or other a use or
modification y the purchaser, its agents, and/or employees, will, at the option of
RJM, e replaced or repaired if it is returned, freight prepaid, to RJM &
Associates, LLC. Equipment that fails under conditions other than descri ed
herein will e repaired at the price of components and la or in affect at the time
of repair.
This warranty is in lieu of all other warranties, expressed or implied, with respect
to the condition or performance of any RJM product, its merchanta ility or fitness
for a particular purpose. RJM is not lia le for any consequential damages.
FCC Compliance
FCC ComplianceFCC Compliance
FCC Compliance
This equipment has een tested and found to comply with the limits for a Class A
digital device pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasona le protection against harmful interference when the equipment
is operated in a commercial environment. This equipment generates, uses, and
can radiate radio frequency energy and, if not installed and used in accordance
with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to
cause harmful interference in which case the user will e required to correct the
interference at his own expense.
Copyright
CopyrightCopyright
Copyright
© 2014 RJM & Associates, LLC
Contents of this pu lication may not e reproduced in any form without the
written permission of RJM. Reproduction or reverse engineering of copyrighted
software is prohi ited.
July 2014
Part Num er 71
7171
71-
--
-00
0000
0023
2323
23

Table of Contents
Table of ContentsTable of Contents
Table of Contents
Introduction
IntroductionIntroduction
Introduction
Important Safeguards and Notices ............................................................................i
Important Warnings and Cautions ............................................................................ ii
Warnings ............................................................................................................ ii
Cautions ............................................................................................................ iii
North American Power Supply Cords ................................................................ iv
Section I
Section ISection I
Section I
eneral Description ................................................................................................ 2
Section II
Section IISection II
Section II
Specifications .......................................................................................................... 4
Section III
Section IIISection III
Section III
Installation ............................................................................................................... 6
Section IV
Section IVSection IV
Section IV
Circuit Description ................................................................................................... 8
Video Path ......................................................................................................... 8
Audio Path ......................................................................................................... 9
PI Path .......................................................................................................... 10
Control Logic ................................................................................................... 10
Status Output .................................................................................................. 11
Power Supply/Regulators ................................................................................ 12
Section V
Section VSection V
Section V
Calibration procedure ............................................................................................ 13
eneral ........................................................................................................... 13
Power supplies ................................................................................................ 13
Video ............................................................................................................... 14
Audio ............................................................................................................... 15
Section VI
Section VISection VI
Section VI
Diagrams ............................................................................................................... 17
External Control Connector Pin Assignment .................................................... 18
PI A & B Connector Pin Assignment ............................................................. 19

i
Important Safeguards and Notices
Important Safeguards and NoticesImportant Safeguards and Notices
Important Safeguards and Notices
Information on the following pages provides important safety
guidelines for both Operator and Service personnel. Specific
warnings and cautions will be found throughout the manual
where they apply, but may not appear here. Please read and
follow the important safety information, noting especially those
instructions related to risk of fire, electric shock or injury to
persons.
ARNING
ARNINGARNING
ARNING
Any instructions in this manual that require opening the
Any instructions in this manual that require opening the Any instructions in this manual that require opening the
Any instructions in this manual that require opening the
equipment cover or
equipment cover or equipment cover or
equipment cover or enclosure are for use by qualified service
enclosure are for use by qualified service enclosure are for use by qualified service
enclosure are for use by qualified service
personnel only. To reduce the risk of electric shock, do not
personnel only. To reduce the risk of electric shock, do not personnel only. To reduce the risk of electric shock, do not
personnel only. To reduce the risk of electric shock, do not
perform any servicing other than that contained in the operating
perform any servicing other than that contained in the operating perform any servicing other than that contained in the operating
perform any servicing other than that contained in the operating
instructions unless you are qualified to do so
instructions unless you are qualified to do soinstructions unless you are qualified to do so
instructions unless you are qualified to do so.
..
.
Symbols and Their Meaning in This
Symbols and Their Meaning in ThisSymbols and Their Meaning in This
Symbols and Their Meaning in This Manual
ManualManual
Manual
The lightning flash with arrowhead symbol, within an equilateral
triangle, alerts the user to the presence of “dangerous voltage”
within the product’s enclosure that may be of sufficient
magnitude to constitute a risk of electric shock to persons.
The exclamation point within an equilateral triangle alerts the
user to the presence of important operating and maintenance
(servicing) instructions in the literature accompanying the
appliance.
This symbol represents a protective grounding terminal. Such a
terminal must be connected to earth ground prior to making any
other connections to the equipment.
The fuse symbol indicates that the fuse referenced in text must
be replaced with one having the ratings indicated.

ii
Important arnin
Important arninImportant arnin
Important arnings and Cautions
gs and Cautionsgs and Cautions
gs and Cautions
arnings
arningsarnings
arnings
•Heed all warnings on the unit and in the operating instructions.
•Do not use this product in or near water.
•Disconnect ac power before installing any options.
•This product is grounded through the grounding conductor of the
power cord. To avoid electrical shock, plug the power cord into a
properly wired receptacle before connecting the product inputs
or outputs.
•Route power cords and other cables so that they are not likely to
be damaged.
•Disconnect power before cleaning. Do not use liquid or aerosol
cleaners; use only a damp cloth.
•Dangerous voltages exist at several points in this product. To
avoid personal injury, do not touch exposed connections and
components while power is on.
•Do not wear hand jewelry or watches when troubleshooting high
current circuits, such as the power supplies.
•During installation, do not use the door handles or front panels
to lift the equipment as they may open abruptly and injure you.
•To avoid fire hazard, use only the specified correct type, voltage
and current rating as referenced in the appropriate parts list for
this product. Always refer fuse replacements to qualified service
personnel.
•To avoid explosion, do not operate this product in an explosive
atmosphere unless it has been specifically certified for such
operation.
•Have qualified personnel perform safety checks after any
completed service.

iii
arnings (continued)
arnings (continued)arnings (continued)
arnings (continued)
•If equipped with redundant power, this unit has two power cords.
To reduce the risk of electrical shock, disconnect both power
supply cords before servicing.
•This equipment may employ laser(s). If it does, they comply
with the current construction requirements of the code of
Federal regulations, title 21, chapter I, subchapter J, sections
1010.2 and 1010.3 and sections 1040.10 and 1040.11.
•Do not attempt to view light output of the laser transmitter, eye
damage may result. Always use an optical power meter to verify
laser output.
•To prevent injury:
Never install telephone wiring during a lightning storm.
Never install telephone jacks in wet locations unless the jack is
specifically designed for wet locations.
Never touch uninsulated telephone wires or terminals unless the
telephone line has been disconnected at the network interface.
Use caution when installing or modifying telephone lines.
Cautions
CautionsCautions
Cautions
•hen installing this equipment, do not attach power cord to
building surfaces.
•To prevent damage to equipment when replacing fuses, locate
and correct the trouble that caused the fuse to blow before
applying power.
•Verify that all power supply lights are off before removing power
supply or servicing equipment.
•Use only specified replacement parts.
•Follow static precautions at all times when handling this
equipment.

iv
Cautions (continued)
Cautions (continued)Cautions (continued)
Cautions (continued)
•Leave the back of the frame clear for air exhaust cooling and to
allow room for cabling. Slots and openings in the cabinet are
provided for ventilation. Do not block them.
•Front door is part of fire enclosure and should be kept closed
during normal operation.
•This product should be powered on as described in the manual.
To prevent equipment damage select the proper line voltage at
the ac input connector as described in the Installation
documentation.
•To prevent damage to this equipment read the instructions in
this document for proper input voltage range selection.
•To reduce the risk of electric shock, ensure that the two power
supply cords are each plugged into a separate branch circuit.
•Circuit boards in this product are densely populated with surface
mount and ASIC components. Special tools and techniques are
required to safely and effectively troubleshoot and repair
modules that use SMT or ASIC components. For this reason,
service and repair of RJM products incorporating surface mount
technology are supported only on a module exchange basis.
Customers should not attempt to troubleshoot or repair modules
that contain SMT components. RJM assumes no liability for
damage caused by unauthorized repairs. This applies to both in-
and out-of-warranty products.
Nort
NortNort
North American Power Supply Cords
h American Power Supply Cordsh American Power Supply Cords
h American Power Supply Cords
This equipment is supplied with molded grounding plug (NEMA 5-
15P) at one end and molded grounding connector (IEC 320-C13) at
the other end. Conductors are CEE color coded, light blue (neutral),
brown (line) and green/yellow (ground).
Operation of this equipment at voltages exceeding 130 VAC will
require power supply cords which comply with NEMA
configurations.

v
Note:
Note:Note:
Note:
This equipment has been tested and found to comply with the limits
for a class A digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against
harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful
interference, in which case the user will be required to correct the
interference at his own expense.

SECTION 1
SECTION 1SECTION 1
SECTION 1
ARTS
ARTSARTS
ARTS-
--
-201B
201B201B
201B
General description
General descriptionGeneral description
General description
The RJM ARTS-201B unctions as an analog input trans er unit that can switch
between two sets o input signals, A and B, either automatically or manually,
using either a local or remote A/B switch. When operating in the automatic switch
mode, the switch is determined by the presence o video on the in-use video
input. I video goes away on the selected (in-use) input and video is present on
the non-selected input, then a switch to the non-selected input will occur. I no
video is present on the non-selected input then no switch will occur.
There are three types o signal inputs to the ARTS-201B or each o the A and B
inputs; analog video, analog audio and GPI. The video input terminates in 75
ohms and has a di erential input to remove any common mode hum. There are
two 75 ohm BNC connectors or the video switch output. There are our channels
o balanced audio. Each audio input is passively looped to a second connector
or monitoring purposes. All balanced audio inputs are high impedance, greater
than 100K ohms. There is a single connector or each audio channel output.
There are ive GPI lines, plus a dedicated line that indicates the A and B
receiver’s health. This line is sensed by the ARTS-201B and indicated on the
External Control connector.
The output o the ARTS-201B will be either the A or B inputs o video, audio and
GPI. During the trans er rom one input to the other, all channels (video, audio
and GPI) switch together. The video switch is not vertical interval.
Some o the other eatures o the ARTS-201B include:
•When the unit is in the automatic mode, i the signal ails on the A input
the unit switches to the B input. A jumper is provided on the module to
allow the user to de ine whether the unit returns to the A input upon return
o the A signal or that the unit remains on the B input until it is manually
returned to the A input. The return-to-A-signal mode can be delayed by an
adjustment to allow rom 1 to 5 seconds a ter return o A signal be ore the
unit switches back to the A input. De ault mode is remain-on-B.
•Relays are provided or both the video and audio signal inputs that will
allow the A input signal to be re-routed to the #1 output, bypassing the
changeover unction, upon loss o power to the changeover unit.
•Video monitor outputs or A and B inputs. These monitor outputs are post-
gain so that they represent the true video input o the A/B switch.

2
•A jumper is provided on the main module that de ines whether the unit
powers up in the automatic or manual mode. De ault mode is automatic.
The audio connections are made with separate three-pin Weco-type connectors
or each audio channel. The connectors have a removable mate that is wired to
the audio cable with screw down compression terminals. The input and output
audio connections are all the same style connectors.
All GPI connections are 9 pin ‘D’. The input ‘D’ connectors or the GPIs are
emale, while the output o the switch is a 9 pin male ‘D’ connector. The switch
between GPIs is made with relays so that the logic level passes through the
switch unaltered. De ault mode is the A signal passing to the output. See the
table on page 19 or the pin out o the connector.
There is an External Control connector, which is a emale 9 pin ‘D’. The External
Control is used or external trans er control and also unction monitoring o the
ARTS-201B. See the table on page 18 or the pin out o the connector.
The rame has space or two power supplies or redundancy, with the output o
each supply voltage diode OR’d with the same output o the other supply. Each
supply has its own AC line connection. I either supply ails or the AC line ails,
then the other supply will keep the unit running.

3
SECTION II
SECTION IISECTION II
SECTION II
ARTS
ARTSARTS
ARTS-
--
-201B
201B201B
201B
Speci ications
Speci icationsSpeci ications
Speci ications
Video:
Video:Video:
Video:
Inputs:
Number 2 (Input A & Input B)
Input type Di erential, video instrumentation
Impedance >100KΩ, bridging to 75Ω
Common Mode Rejection (CMRR) >70dB
Return Loss >46dB @ 5MHz
Level 1 volt peak-to-peak nominal, 2v max
Maximum level, (di erential) ±2v
Outputs:
Number 2
Return loss >35dB @ 5MHz
Impedance 75Ω 0.1%
Level 1 volt peak-to-peak nominal, 2v max
Horizontal Tilt 0%, DC coupled
Vertical Tilt 0%, DC coupled
Di erential gain <0.2%, 10 to 90% APL @ 3.58MHz
Di erential phase <0.2º, 10 to 90% APL @ 3.58MHz
Chrominance/luminance delay <±5nsec
Hum <1mV
Signal to noise ratio >70dB weighted to 20MHz
Crosstalk >-60dB @ 5MHz
Response, minimum equalization <±0.05dB to 5MHz
<±0.2dB to 10MHz
+0, to -1dB @ 20MHz
Response, maximum equalization <±0.1dB to 5MHz
(assumes 1505A or 8281 coax) <±0.25dB to 10MHz
+0, to -1dB @ 20MHz
Di erential delay <0.5º @ 3.58MHz
DC o set <±50mV

4
ARTS
ARTSARTS
ARTS-
--
-201B Speci ications, (cont.)
201B Speci ications, (cont.)201B Speci ications, (cont.)
201B Speci ications, (cont.)
Audio:
Audio:Audio:
Audio:
Inputs:
Number 8, (4 Channels Input A & 4 Channels
Input B)
Impedance >100KΩ
Input type Balanced, di erential
Common Mode Rejection (CMRR) >70dB, 20Hz to 20KHz
Maximum level +22dBu
Outputs:
Number 4 (1 per channel)
Output type Balanced around ground
Impedance <10Ω
Maximum level +22dBu
Gain Unity, ±6dB by internal adjustment
Total Harmonic Distortion (THD) <0.02% 20Hz to 20KHz @ +24dBu
Intermodulation Distortion (IMD) <0.02% 4:1 SMPTE
Response <±0.1dB, 20Hz to 20KHz
+0, -0.3dB @ 100KHz
Crosstalk >80dB re erenced to 0dBu
Signal to noise ratio >86dB
GPI Inter ace:
GPI Inter ace:GPI Inter ace:
GPI Inter ace:
Connector type 9-pin “D”
Contact closure current 0.5 Amp maximum
Contact closure power 10VA maximum
Power requirements 115/230VAC, 50/60 Hz
36VA maximum
(18VA each power supply)
Size 1.75” x 19” x 10”
Weight ≈7 lbs 3 kg
•Speci ications and design are subject to change without notice.

5
SECTION III
SECTION IIISECTION III
SECTION III
ARTS
ARTSARTS
ARTS-
--
-201B
201B201B
201B
Installation
InstallationInstallation
Installation
The RJM ARTS-201B input trans er unit is designed to be mounted in a standard
19” equipment rack. There are no special cooling requirements though care
should be taken to ensure that extremely hot equipment is not installed directly
beneath. It is also recommended that, i possible, one rack-unit o space be le t
above the unit.
Unless speci ied at the time o order, the ARTS-201B is shipped rom the actory
or nominal 117VAC 60Hz power. The unit is supplied with a 120V type AC plug.
I it is desired to operate at 230VAC 50Hz, then a selector switch must be set on
the power supply. The supply is removed rom the rame, the switch set to
230VAC, and then the supply replaced in the rame.
The two analog video inputs are internally terminated at 75Ω. The second
connector or each input, marked MON, can be used as a monitor o the input.
This connector receives its signal rom an internal post-gain ampli ier, which
allows the operator to con irm and make gain adjustments to the signal that is
being ed to the A/B video switch. I these connectors are not used, they should
be terminated.
Audio input and output cables must be wired to con orm to the silk-screen on the
rear o the rame. All connectors have the same orientation. Shield (or ground) is
the center o the three pins. Use care to maintain the polarity as shown, so that
input phases match the output.
An internal adjustment, labeled VID DELAY (R28
R28R28
R28), allows or a delay o the
automatic changeover rom one input signal to the other. This has the e ect o
delaying the detection o the absence o video or up to one second. I vertical
pulses become present again on the in-use channel be ore the one second time-
out, the video presence will not indicate a loss o video. This keeps the logic rom
switching to the opposite input or very short losses o video. Moving the delay
clockwise will increase the delay.
I the unit is to be switched remotely by a computer or similar device please note
that the ground signal applied to pins #4 or #9 o the External Control connector
must be maintained or a minimum o 20msec in order or the vertical interval
switch pulse to operate the logic. These pins are normally held at +5v on the
module.

6
Two jumpers are provided on the main module to allow or certain user de ined
operations:
J9
J9J9
J9 is utilized to determine whether the ARTS-201B unit is powered up in the
automatic or manual mode. A ter power up, the pushbutton inside the ront cover
can always be used to override the power up selection.
When the unit is in the automatic mode, i the signal ails on the A input the unit
switches to the B input. A jumper (J10
J10J10
J10) is provided on the module to allow the
user to de ine whether the unit automatically returns to the A input upon return o
A signal or whether it remains on the B input until it is manually returned to the A
input. The return-to-A-signal mode can be delayed by an adjustment (R177
R177R177
R177) to
allow rom 1 to 5 seconds a ter return o A signal be ore the unit switches back to
the A input. This is included to allow the A signal to stabilize be ore returning to
the A signal position. The manual changeover pushbutton switch located in the
ront cover, as well as the remote changeover pins in the External Control
connector continue to provide or manual operation o the unit.

7
SECTION IV
SECTION IVSECTION IV
SECTION IV
ARTS
ARTSARTS
ARTS-
--
-201B
201B201B
201B
Circuit description
Circuit descriptionCircuit description
Circuit description
Video Path
Video PathVideo Path
Video Path:
Only one signal path, A, will be described since both A and B paths are the
same. The signal comes rom the input BNC on the motherboard and onto the
main board where it is terminated in 75 ohms. The video is then ed into the
di erential ampli ier U16. This ampli ier is a true di erential amp, and will reject
common mode signals such as AC line hum due to ground loops or AC cabling
running in parallel with the video cable. The input stage’s gain is set with a
variable pot R71 that can be adjusted to compensate or any gain inaccuracies in
the remainder o the path to the output. The next stage has an adjustable
equalization circuit to compensate or cable runs o up to 100 meters o Belden
8281 cable, or equivalent. This essentially operates as a unity gain stage when
the R6 pot is adjusted to the end closest to the ampli ier’s output. As the pot is
adjusted to the opposite end, the equalization network attached to the wiper
connection o R6 begins to have more e ect. The equalization network, by rolling
o the higher requencies, causes the gain o the ampli ier to rise at higher
requencies. Resistor R11 sets the DC gain and low requency gain o the
ampli ier, which compensates or the cable loss at DC rom the cable resistance.
There are three di erent destinations or the video signal a ter the gain stage.
One is to the sync separator U19, which is used to determine video presence. A
second destination is to the monitor ampli ier U18, which has a gain o two to
drive a source terminated output. U18’s input is also shared by the output
ampli ier/mux, U21, which does the actual selection o either the A or B input. A
resistor-capacitor divider network is shared by both the U18 and U21 ampli iers,
which is used to adjust the overall requency response o both the monitor and
main output o the RTU. The output ampli ier drives two video output BNC
connectors through the 75 ohm source resistors R23 and R24.
A dual orm C relay has been inserted into the video path. One section, K4B, is
located at the A Video Input and selects whether the input signal passes to U16,
or whether it bypasses the entire 2x1 switching system. The other section, K4C,
is located a ter the 2x1 switch, U21. During normal operation the relay coil is
energized and K4B passes the input signal through the input ampli ier U16,
equalizer U17 and 2x1 switch U21 to K4C to the output BNC connectors. Should
there be a power ailure within the unit, the relay drops to the relaxed mode, and
the video input signal is routed directly to PGM output #1. When power is
restored, the relay coil is re-energized and the signal is again routed to the 2x1
switch output via U16, U17 and U21. The relay coil is powered rom the -15 volt
regulator U37.

8
The sync separator U19, which is a vertical sync output, is used to trigger a re-
triggerable one shot. The one shot timing is adjusted by the current into C22 rom
the current source comprised o Q1 and U38. The current source is adjustable
with R28 over a range such that timing can be varied rom 100ms to 1 second.
This has the e ect o delaying the absence o video or up to one second. I
vertical pulses become present be ore the one second time-out the video
presence will not indicate a loss o video. This keeps the logic rom switching to
the opposite input or extremely short losses o video.
Audio Path:
Audio Path:Audio Path:
Audio Path:
Only one path will be described since all our inputs and paths are alike. The
input comes into a di erential stage U39A, with high impedance bu ers to keep
the input impedance at or above 100K ohms. U1 provides the actual di erencing
o the balanced inputs. Common mode signals such as AC line hum are rejected
by this stage. This stage has a gain o –6 dB which is made up in the balanced
output stage. The output o U1 eeds the switch o U9 which selects either A
inputs or B inputs. The output o the switch eeds an adjustable gain stage U11,
which compensates or gain inaccuracies o the output stages. The output is a
balanced output which has a gain o +6 dB when measured across the output
positive to negative output pins.
As described above in the video path, orm C relays are included in all our
output channels which provide a path rom module input directly to module
output in the event o power ailure o the ARTS-201B. All our channels o A
audio are also routed to NC contacts on relays K5, K6, K7 and K8. The NO
energized side o these relays comes rom the our output ampli iers, U11, U12,
U13 and U14 and the common pin connects to the audio output connectors.
Should there be a power ailure within the unit, all our relays drop to the relaxed
mode, and the audio input signal is routed directly to PGM output. When power is
restored, the relay coils are re-energized and the output signal is again derived
rom the 2x1 switches U9 and U10. The relay coils are powered rom the -15 volt
regulator U37.

9
GPI Path:
GPI Path:GPI Path:
GPI Path:
The A and B GPI inputs enter on emale 9 pin ‘D’ connectors. The output GPI
connector is a 9 pin ‘D’ male connector. The A and B GPI’s each go to opposite
sides o a orm C relay with the common pin o the relay going to the output GPI
connector. In the relaxed position, the A input is passing through the relay to the
output connector. The relay is controlled by a logic level to the input o U15:H.
The output o U15:H is an open collector output which saturates to ground. When
the collector is turned on, it turns on relays K1 through K3, which will select the B
GPI inputs. One o the GPI lines is dedicated to receiver health, which is
monitored by the logic on board and reported on one o the external control
outputs.
Control Logic:
Control Logic:Control Logic:
Control Logic:
Whether or not A inputs or B inputs are selected is determined by the state o D
lip- lop U27:B outputs. There are two ways to e ect a change on the outputs o
U27:B. One is with the preset and clear inputs, and the other is with the clock
input. The preset and clear lines are a ected by the “Select A” and the “Select B”
inputs that come in through the External Control connector. The clear line is also
a ected by the logic state o the Power on Reset circuitry o C30, D20 and either
R47 or R175 depending on the position o jumper J9. Normally the preset and
clear is always driven by a high state but at power up a low logic level at the
input to U32:D is inverted to a high state which causes XOR gate U31:D to invert
the normally high level rom U29:C to a low logic level. This clears U27:B, putting
a logic high on the Q output, which orces selection o the A inputs at power on.
The Select A or Select B control signals are bu ered by U31:A and :B and their
logic sense can be inverted by opening or closing S4:A and :B. I either Select
input is activated a positive going edge will be produced at the input to the one
shot U28:B. I S4:D is closed, an output pulse orms the one shot, which will gate
a low logic level through U29 to either the preset or clear o U27:B. This causes
the A or B inputs to be selected. I the S4:D is open then the selected input on
Select A or B lines will cascade through U29 gates to always set or clear U27:B
as long as that input is activated, whereas with S4:D open a pulse will set or
clear U27:B when the Select lines are irst activated. Leaving S4:D open causes
an override o the second means to change the state o U27:B, which is through
the clock input to U27:B.
There are two ways to clock U27:B which will cause the output to toggle between
states. First is rom the A/B Select momentary switch S2 on the ront edge o the
board. Pushing S2 triggers one shot U26:A which sends a positive going pulse to
the clock input o U27:B causing it to toggle and select the opposite input. The
second way is caused by the loss o video on the active input. Assume the case
where A is selected with video present and B has video present. Under these

10
conditions, i A video goes away a positive going pulse edge will be created at
the input to U27:B clock and the output will toggle to the B inputs. This can only
occur i the unit is in Auto mode. U32:B locks out edges that could change the
selected inputs due to loss o video on the active channel.
The Manual/Auto unction that controls NAND gate U32:B is activated by either
the Remote Auto/Man input rom the External Control connector or rom the ront
edge momentary switch S1 or by the position o J9 at power on. S1 triggers one
shot U26:A, which toggles U27:A between manual and auto modes. The Remote
Auto/Man input can have its logic polarity changed with S4:C. A ter being
bu ered by U31:C, the remote input triggers one shot U26:B, which in turn
triggers U26:A. This then toggles the state o the Manual/Auto lines. At power on,
i the J9 jumper is positioned to AUTO then the action o C30 charging will preset
the Q output o U27:A high, which sets the system to the AUTO mode.
Alternately, i the J9 jumper is set to MANUAL, U27:A will be cleared at power on
and the system will set to MANUAL mode.
AUTO RETURN TO A INPUT operates only in the AUTO mode. As long as the B
input is selected and A video is not present U49 is held in its reset state. The
action o A video going away sets a high on the Q output o U52:A. This high is
ed to one o the inputs o NAND gate U50:D, which will allow a Force-A signal to
pass through to the output o U51:D. Once a Force-A signal has orced the
system back to the A input, U51:D will clear U52:A and the Force-A signal will
not have an e ect until the A video input is not present again. The A signal must
be present or a time-out period set by R177, rom approximately 1 to 5 seconds.
The 3-input NAND gate, U53:A, insures that no more pulses rom the counter
U49 will be created or the Force-A signal. The delay created by R184 and C132
insures that a 4µsec pulse will be present or the Force-A signal.
Status Outputs:
Status Outputs:Status Outputs:
Status Outputs:
Status is available or di erent unctions on the External Control connector. Each
output is an open collector output with a jumper-selectable pull-up resistor o 1K
ohms to +5 volts. There are ive such outputs. The irst one is A input health and
A video present, which will go to a high state i input health is bad or video is not
present. Second output is the same as the irst but or the B input health and B
video present. The third output indicates the health o the power supplies in the
rame. I either supply goes down then the output goes high. The ourth status
output is or switch selection status. A low on this output indicates the A is
selected and a high indicates B is selected. The inal output indicates the number
o inputs, where a low indicates one input and a high indicates two inputs. This
indication is changed with a slide switch, S3.

11
Power Supply / Regulators:
Power Supply / Regulators:Power Supply / Regulators:
Power Supply / Regulators:
The unregulated voltage to the voltage regulators on the main board comes rom
either o two power supplies that can be removed at the ront o the RTS rame
or service and replacement. Each unregulated supply has an input use and a
115/230VAC selector switch, and contains the circuitry that monitors the positive
and negative outputs, and reports the power supply condition on one pin to the
main board. A dual color LED on the ront o the power supply displays its health.
Green indicates normal operation, or healthy condition. Red indicates a problem
with that supply. The output o the supply is diode OR’d to its respective supply
bus.
There are our regulators on the main board, one or each o the voltages. Three
o the regulators are linear voltage regulators. U36 controls the +15 volts, U37
the -15 volts and U43 controls the -5 volts. The +5 volts is controlled by a
switching regulator U35.

12
SECTI
SECTISECTI
SECTION V
ON VON V
ON V
ARTS
ARTSARTS
ARTS-
--
-201B
201B201B
201B
Calibration procedure
Calibration procedureCalibration procedure
Calibration procedure
Equipment required:
Dual channel oscilloscope, >50MHz.
Video test set.
Sweep generator.
Vectorscope.
Audio generator and analyzer.
Digital voltmeter.
100 meter reel o 8281 or 1505A coaxial cable.
General.
General.General.
General.
In order to satis actorily complete this procedure the ARTS-201B must be
operating correctly. Be ore attempting to calibrate the unit ensure that all audio
and video paths, rom input to output, are present, and that all logic and tally
unctions are correct. Check that all LEDs on the ront panel illuminate correctly
and that the GPI connector unctions are present and correct.
1. Power supplies.
1. Power supplies.1. Power supplies.
1. Power supplies.
The voltages shown on the main board test points are nominal. The circuits
employed in the ARTS-201B are not voltage level sensitive and the voltage
values are not adjustable.
Remove the PS#2 power cord rom the source o AC.
Measure the +15v TP, +14.5v to +15.5v.
Measure the -15v TP, -14.5v to -15.5v.
Measure the +5v TP, +4.8v to +5.2v.
Measure the -5v TP, -4.8v to -5.2v.
Replace the PS#2 power cord and remove the PS#1 power cord rom the source
o AC.
Measure the +15v TP, +14.5v to +15.5v.
Measure the -15v TP, -14.5v to -15.5v.
Measure the +5v TP, +4.8v to +5.2v.
Measure the -5v TP, -4.8v to -5.2v.
Replace the PS#1 power cord.