Kramer Electronics VS-1211 user manual Audio Signal, Problem Remedy

Problem	Remedy
Noise bars are “ rolling” up or down in the output image	Hum bars (ground loop) are caused by a difference in the
or:	ground potential of any two or more devices connected to
	your signal path. This difference is compensated by passing
Low frequency hum in the output signal	that voltage difference through any available
	interconnection, including your video cables.
		WARNING!
		Do not disconnect the
		ground from any piece of
		video 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.

14.3 Audio Signal

Problem	Remedy
No audio at the output device,	1.	Confirm that your sources and output device are powered on and connected
regardless of input selected		properly. Audio signals connected to the input of your switcher should be properly
		wired to the output of your source. Audio signals connected to output of your
		switcher should be properly wired to the input of your switcher or recorder.
	2.	Confirm that any other switchers in the signal path have the proper input and/or
		output selected. Pay special attention to input switchers that may be built into your
		switcher or recording device.
Audio level is too low	1.	Confirm that the connecting cables are of high quality and properly built. Take
		special care in noting the wiring configuration of balanced to unbalanced cables.
	2.	Check level controls located on your source input device or output display or
		recorder.
The switcher switches the	One of the audio cables leading to the main board is disconnected and cannot transfer
video but does not switch the	the switch command to the video.
audio.
The switcher will not switch	The RS-485 control is fed by a flat cable from the upper audio board to a socket on
via the RS-485 control	the main board. One of its connectors may be disconnected.
	Turn OFF the mains switch, remove the power cord from the mains socket and
	carefully remove the cover of the switcher. Verify that all the flat cables from the
	main board to the control board, from the audio board to the main board and from the
	switchboard to the main board are undamaged and properly connected.
		NOTE
		Sometimes connectors work loose and have to be reinserted.
		(Perform this firmly but with care).

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