Kramer Electronics VP-31 - Manual (Page 21)

Problem Remedy
Noise bars are "rolling"
up or down in the
output video image
or:
Low Frequency Hum in
the output audio signal
Hum bars (ground loop) are caused by a difference in the ground potential of any
two or more devices connected to your signal path. This difference is compensated
by passing that voltage difference through any available interconnection, including
your video cables.
WARNING!
DO NOT DISCONNECT THE GROUND FROM ANY
PIECE OF VIDEO/AUDIO EQUIPMENT IN YOUR
SIGNAL PATH!
Check the following to remove hum bars:
1. Confirm that all interconnected equipment is connected to the same phase of
power, if possible.
2. Remove equipment connected to that phase that may introduce noise, such as
motors, generators, etc.
3. Disconnect all interconnect cables and reconnect them one at a time until
ground loop reappears. Disconnect the affected cable and replace, or insert an
isolation transformer in the signal path.
Control (VP-61RS only)
Problem Remedy
No control of switcher
from VS-2000 control
panel
1. Confirm that the connecting cable is wired for pins 1-9 straight through.
2. Confirm that all DIP switches on the switcher have been set properly. Keep in
mind that if you are controlling only one switcher on a specific port, that
switcher must be assigned the ID of “1”.
3. If controlling more than one switcher on a single port, all switchers must be of
the same type and power to all switchers must be on.
4. Confirm that you have the proper machine number and control port selected on
the VS-2000. For instance, if you are controlling a single machine on port 1,
then both of these should be set to “1”.
5. Confirm that you have the proper switcher type selected on the VS-2000. If
not, go back to Section 9.4.1 of this manual “The VS-2000 System”.
No control of switcher
from the PC software
1. Confirm the wiring of the connecting cable. This pin configuration may be
found in Section 10 “CONNECTING TO A PC”. Cable length should not
exceed 25 feet.
2. Confirm that all DIP switches on the switcher have been set properly. Keep in
mind that if you are only controlling one switcher on a specific port, that
switcher must be assigned the ID of “ 1”.
3. If controlling more than one switcher on a single port, all switchers must be of
the same type and power to all switchers must be on.
4. Confirm that the baud rate of your computer COM port is set to the same as
that of your switcher (e.g 9600-Baud). Confirm that the proper COM port is
selected in the control software.
5. With custom software, do not send multiple commands at the same time. Wait
for the switcher to reply to a command before sending the next command.
6. Confirm that the computer you are using supports true RS-232C protocol.
Computers such as the Apple Macintosh do not!