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Troubleshooting and roadblock

A project log for CRT Viewfinder NIR Scope

Display near infrared video on a CRT viewfinder

jeffrey-jacquesJeffrey Jacques 01/28/2019 at 03:310 Comments

So all I'm getting are some flashing scan lines during pi booting. Went through the extra wires alternating pulling them 5V / 3V high or low. Got some bright squiggles on CHR high and another pulled high seems to degauss or reset.  Need to work from a known good so crimped a Dupont connector to an RCA video cable to an input on my TV. We got video, so the Pi is working. Hmmm maybe impedance issue? Plug on the TV reads 75 ohms, 3K ohms on the viewfinder video input... tied video in to ground with 68 ohm resistor (closest I had) a little more squiggly on booting. Have to wait for an order of 75 ohm resistors to arrive. If that's not it I may be stumped / something is bad.

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