Video AGC level modification to Supercircuits PC23C

During attempts (so far unsuccessful) to modify the video AGC from average detecting to peak detecting, I discovered that if the video level detect output was connected directly to the AGC amplifier (+) input, the circuit seemed to respond to much smaller areas of illumination. While this is not the total cure for planetary imaging, with this modification you can leave the AGC in auto (or not do the AGC auto/manual modification at all) and the camera will boost the video gain when needed but will not cause as much clipping as an un-modified camera.

If you have already done the "AGC auto/manual" modification, this modification will give similar results, but the AGC can be left in AUTO all the time, bringing up the gain in dark areas like star fields.

Unfortunately, due to the board layout (on a version 1 camera, anyway) this modification is not as easy to do since it involves soldering directly to two IC pads. Do not attempt this unless you are comfortable with your micro soldering skills and have a small iron with a very small tip...... as well as a de-soldering tool of some sort if you inadvertantly bridge two adjacent pins!

To make the AGC level modification, merely (yeah, right) connect pin 13 to pin 19. This is best done with some very fine wire such as wire wrap wire. With a magnifying glass and a very small iron tip, it isn't too hard. But make sure you have some form of de-soldering equipment in case you bridge the pads. Also be very careful not to overheat the board, since the foil can be damaged by excessive heat and lift away from the board.

Note that I have shown the component location for the "version 1" camera. However, since the modification involves connecting directly to the IC pads, there should be no reason this modification will not work on a version 2 camera as well.

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