Additional Video Rack Notes

The purpose of the time base corrector (TBC) is to clean the video signals coming off the 1/2" VHS decks (due to the playback speed not precisely matching the recording speed). You can also adjust video levels. It's critical to do this when recording 1/2" signal onto the Abekas, and perhaps wise when recording to the other 1/2" deck or the 3/4" decks.

The input of the TBC is decided by the TBC/Scope Switch, and should usually be the 1/2" left VHS deck. On the Editor switch you should select TBC.

Here are some example configurations:

Record VHS (e.g, left VCR) to Abekas:

Select 1/2" Left on the TBC/Scope Switch.
Select TBC on the Editor Switch.
Select NTSC Decoder on the RGB Record Switch.
Select Abekas on the RGB Playback Switch.
Select Video-In on the Abekas remote keypad.
Proceed with recording.
To view the result, deselect Video-In on the Abekas remote keypad and select NTSC Encoder on the Editor Switch, then hit Play on the Abekas remote keypad.

Record TBC'ed VHS (e.g., left VCR) to VHS (e.g., right VCR):

Select 1/2" Left on the TBC/Scope Switch.
Select TBC on the Editor Switch.
Proceed with the recording.
To view the result, select 1/2" Right on the Editor Switch.

Note: When the TBC is not receiving video (as in when it is connected to a VHS VCR that is turned off), it will display nonsensical output, usually fading to bright white. Do not be alarmed. As soon as you give it a signal, it will behave normally.

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Brian L. Curless / Stanford University / May 3, 1994

Major modifications: Fri Dec 22 1995 Tamara Munzner