Texas Instruments UM1381 User manual

Texas Instruments
Home Computer
Accessory
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Model UM138
OPERATING GUIDE
The UM1381 unit is a combination video
modulator and isolation switch designed
for use with the Texas Instruments Home
Computer. With the Video Modulator,
your own television set (color or' black &
white) can be used as a computer
display, eliminating the need for a
monitor for your Home Computer.
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Copyright © 1981 Texas Instruments Incorporated

The UM 1381 Video Modulator is designed to be used
with a standard television set having 300-ohm. flat.
twin-lead antenna connections. If you have a coaxial
antenna system that connects directly to your
television set with a round screw-on connection, you
have a low-impedance antenna system (typically 75
ohms). To comply with Federal Communications
Commission guidelines, you will need to purchase a
“Balun matching transformer” from a local television
or electronics shop to permit connection of the
antenna cable to the Video Modulator. If your
television has a low impedance antenna system and
receives UHF stations (Channel 13 and up). be sure to
obtain a Balun matching transformer with both VHF
and UHF output leads to the television set. Connect
the transformer and check your television for normal
reception of all channels before connecting the
UM 1381 Video Modulator.
INSTALLATION
The Video Modulator includes the following parts:
I The modulator/switch unit
I An attached 6-inch television interconnect
cable (connects to your television set)
I An attached computer interface cable
(connects to the computer console)

6" TELEVISION
INTERCONNECT
CABLE (See Step 2)
TV AN TENNA/
VHF ANTENNA /
TERMINALS
(See Step 3)
\ CHANNEL
SELECT SWITCH
COMPUTER INTERFACE CABLE
WITH 5-PIN JACK (See Step 4)
No special tools are required to connect the compact,
easy-to-install Video Modulator to your television set.
A screwdriver is the only tool you‘ll need. Two self-
gripping strips (on the back of the unit) allow you to
mount the Video Modulator directly on your
television set.
Follow these steps to install the unit.
Step 1. Turn the television OFF. Then, loosen the
screws on the VHF antenna terminals on
your television set. and remove the antenna
cable.
Step 2. Connect the Video Modulator television
interconnect cable. marked TO TV RECEIVER
VHF TERMINAL, to the VHF antenna terminals
on the television set. Then retighten the screws.

Step 3. Connect the television VHF antenna cable to
the Video Modulator antenna terminals,
marked ANTENNA, and tighten the screws.
Step 4. Plug the computer interface cable's 5-pin
jack into the 5-pin socket on the right side
of the back of the main console (when
console is viewed from rear). Be sure the
pins are properly aligned with the socket to
avoid bending pr breaking them. Connect
the plug firmly, but do not force it into
position.
Step 5. Use the attached self-gripping strips to
mount the Video Modulator on the
television set. Peel off the paper backing
and press the unit against a flat surface on
your television set. (The strips will support
' the modulator's weight and relieve strain
on the cable connections.)
A NOTE ABOUT FCC RESTRICTIONS
In order to prevent possible interference with other
television sets in your area, please observe the
following Federal Communications Commission
restrictions:
1. DO NOT add any extra lead-in wire to the
television interconnect cable when attaching the
UM 1381 Video Modulator to your television set.
2. DO NOT connect the UM 1381 Video Modulator to
more than one television set at a time.
3. DO NOT attach the television interconnect cable
on the UM 1381 Video Modulator to any television
antenna lead-in wire or cable television outlet.
4. DO NOT connect any wires. other than the UM1381
Video Modulator cables, to your television set
and/or antenna when you are using the computer
system.

OPERATION
There are two switches on the Video Modulator. At
one end is a channel select switch. marked
CHANNEL SELECT 4 3. Set the switch to either
Channel 3 or 4. If there is a television station
operating on one of these channels in your area,
select the other channel on the modulator. Then. set
your television to the same channel.
CHANNEL SELECT
SWITCH
On the top of the Video Modulator you’ll see a switch
(the isolation switch) marked TV ANTENNA at one
end and MODULATOR at the other. Set this switch to
MODULATOR.
TV/MODULA TOR
S WITCH

That's all there is to it. Turn on your television set
and computer. and you're ready to start. Adjust the
controls (including “fine tuning") of the television set
for optimal picture clarity and most pleasing colors,
just as you would for normal television reception.
You can leave the Video Modulator attached
to your television set all the time. Whenever you
want to watch your favorite television programs. just
slide the TV ANTENNA/MODULATOR switch back to
the TV position.
PROTECTION INDICATOR
The protection indicator light should be off under
normal operating conditions. If for some reason the
light is on, turn the computer off. wait several
seconds, and turn it on again. The indicator light
should then be off.
IN CASE OF DIFFICULTY
The picture that you get on the screen when using
your television as a computer display will only be as
good as the picture you normally get on your
television set. Before attaching your Video
Modulator, make sure that your television set is in
good working order.
If your television/computer system does not seem to
be working properly, check first to be sure that both
the television set and the computer are turned on.
Then follow this checklist to identify and correct the
problem.
Problem Solution Steps
No picture 1. Check all connections to be sure
at all the modulator is correctly
attached to the television and
computer (see INSTALLATION).
Make sure the VHF antenna
cable is connected to the VHF
antenna terminals (not the UHF
antenna terminals, if your TV
has UHF terminals).

Problem
Poor-quality
picture
Solution Steps
Check the wall outlet where the
television set is plugged in. Is it
"live"? (Test it by plugging in a
lamp.)
Be sure the TV ANTENNA/
MODULATOR switch is set to
MODULATOR.
Be sure the Channel Select
switch on the modulator is set to
the same channel as the
television set.
Adjust the fine-tuning control
through its full range.
Be sure the television set
operates without the UM 1381
Video Modulator connected.
Use the fine-tuning control on
your television set to bring in
the best possible picture.
If your television set has a
300/75-ohm antenna terminal
switch, make sure the switch is
set to 300 ohms.
Check to see if any power
appliance or equipment (hair
dryer, mixer, drill, saw, etc.) is
causing interference.
If your television has a
sharpness (or “peaking")
control, adjust it for optimal
character sharpness.
If you continue to have difficulty with the Video
Modulator, consult the service information below or
see the “Maintenance and Service Information"
section in the User's Reference Guide.

SERVICE INFORMATION
If the UM1381 Video Modulator is in warranty. it will
be repaired or replaced under the terms of the
Limited Warranty. Out-of-warranty units in need
of service will be repaired or replaced with
reconditioned units (at TI‘s option), and service rates
in effect at the time of return will be charged.
Because our Service Facility serves the entire United
States, it is not feasible to hold units while providing
service estimates. For advance information
concerning our flat-rate service charges, please call
our toll-free number.
EXCHANGE CENTERS
If your Video Modulator requires service, instead of
returning the unit to a service facility for repair or
replacement, you may elect to exchange the unit for
a factory-reconditioned Video Modulator of the same
model (or equivalent model specified by TI) by going
in person to one of the exchange centers which have
been established across the United States. A
handling fee will be charged by the exchange center
for in-warranty exchanges of the Video Modulator
unit. Out-of-warranty exchanges will be charged at
the rates in effect at the time of the exchange.
To determine if there is an exchange center in your
area, look for Texas Instruments Exchange Center in
the white pages of your telephone directory, or look
under the Calculator and Adding Machine heading in
the yellow pages. Please call the exchange center for
availability and exchange fee information. Write the
Consumer Relations Department for further details
and the location of the nearest exchange center.

FOR GENERAL INFORMATION
If you have questions concerning Video Modulator
repair, please call our Customer Relations
Department at 800-858-4565 (toll free within the
contiguous United States except Texas] or
800-692-4279 within Texas. The operators at these
numbers cannot provide technical assistance.
For technical questions, you can call 806-741-2663.
Please note that this is not a toll-free number, and we
cannot accept collect calls.
As an alternative, you can write to:
Consumer Relations Department
Texas Instruments Incorporated
P.O. Box 53
Lubbock, Texas 79408

THREE-MONTH LIMITED WARRANTY
FOR UM1381 VIDEO MODULATOR
THIS TEXAS INSTRUMENTS VIDEO MODULATOR
WARRANTY EXTENDS ONLY TO THE ORIGINAL
CONSUMER PURCHASER OF THE VIDEO
MODULATOR.
WARRANTY DURATION
This Texas Instruments Video Modulator is
warranted for a period of three (3) months from the
date of original purchase by the consumer.
WARRANTY COVERAGE
This Texas Instruments Video Modulator is
warranted against defective materials or
workmanship. THIS WARRANTY IS VOID IF THE
VIDEO MODULATOR HAS BEEN DAMAGED BY
ACCIDENT. UNREASONABLE USE, NEGLECT.
IMPROPER SERVICE OR OTHER CAUSES NOT
ARISING OUT OF DEFECTS IN MATERIALS OR
WORKMANSHIP.
WARRANTY PERFORMANCE
During the above three-month warranty period, your
Video Modulator will be repaired or replaced with a
new or reconditioned unit of the same or equivalent
model (at TI's option) when the unit is returned by
prepaid shipment to a Texas Instruments Service
Facility listed below. The repaired or replacement
unit will be warranted for three months from date of
repair or replacement. Other than the postage
requirement. no charge will be made for the repair or
replacement of in-warranty units.
Texas Instruments strongly recommends that you
insure the unit for value. prior to shipment.

THREE-MONTH LIMITED WARRANTY, continued
WARRANTY DISCLAIMERS
ANY IMPLIED WARRANTIES ARISING OUT OF THIS
SALE, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE, ARE
LIMITED IN DURATION TO THE ABOVE THREE-
MONTH PERIOD. TEXAS INSTRUMENTS SHALL NOT
BE LIABLE FOR LOSS OF USE OF THE PRODUCT OR
OTHER INCIDENTAL OR CONSEQUENTIAL COSTS.
EXPENSES, OR DAMAGES INCURRED BY THE
CONSUMER OR ANY OTHER USER.
Some states do not allow the exclusion or limitation
of implied warranties or consequential damages, so
the above limitations or exclusions may not apply to
you in those states.
LEGAL REMEDIES
This warranty gives you specific legal rights. and you
may also have other rights that vary from state to
state.

THREE-MONTH LIMITED WARRANTY, continued
TEXAS INSTRUMENTS CONSUMER SERVICE
FACILITIES
U.S. Residents
Texas Instruments Service Facility
2303 North University
Lubbock, Texas 79415
Canadian Residents
Geophysical Services Incorporated
41 Shelley Road
Richmond Hill, Ontario, Canada L4C5G4
Consumers in California and Oregon may contact the
following Texas Instruments offices for additional
assistance or information.
Texas Instruments Consumer Service
831 South Douglas Street
El Segundo, CA 90245
[phone]
Texas Instruments Consumer Service
6700 Southwest 105th
Kristin Square, Suite 110
Beaverton, Oregon 97005
[phone]
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TEXAS INSTRUMENTS
INCORPORATED
DALLAS, TEXAS
Printed in USA. 1048641-3