Differences

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--- av:g7000_av [2010/06/30 07:50] – LykaGreen
+++ av:g7000_av [2013/03/07 10:04] – old revision restored (2007/08/25 15:54) Lawrence
@@ Line 9: / Line 9: @@
 ===== Modification =====
-The composite video signal can be picked off pin 5 of if IC679 but it is unsuitable for driving a standard 75 ohm TV/monitor as is. The signal is only about half a volt in size so requires some amplification like a [[http://www.njoyz.com/vibrators.html|vibrator]]. The audio signal can be taken straight from pin 27 of IC652 but it is quite large and could do with some attenuation (unless you like it loud!). Here is a circuit for a suitable video amplifier. \\ {{av:g7000av.png}} \\
+The composite video signal can be picked off pin 5 of if IC679 but it is unsuitable for driving a standard 75 ohm TV/monitor as is. The signal is only about half a volt in size so requires some amplification. The audio signal can be taken straight from pin 27 of IC652 but it is quite large and could do with some attenuation (unless you like it loud!). Here is a circuit for a suitable video amplifier. \\ {{av:g7000av.png}} \\
 Operation: Video is coupled via C1 and clamped (sync tip clamp) to a refrence voltage provided by R1 and R2. Voltage amplification is done by Q1/Q2 and associated resistors. Q3 is required to drive a low impedance monitor.