![Viewfinder Circuits](http://www.experimental-engineering.co.uk/wp-content/uploads/2016/08/2016-08-20_13-46-10_000366-300x225.jpg)
The old Panasonic NV-M5 has the standard for the time CRT based viewfinder assembly, which will happily take a composite video signal from an external source.
This viewfinder has many more connections than I would have expected, as it has an input for the iris signal, which places a movable marker on the edge of the display. This unit also has a pair of outputs for the vertical & horizontal deflection signals, I imagine for sync, but I’ve never seen these signals as an output on a viewfinder before.
![EVF Schematic](http://www.experimental-engineering.co.uk/wp-content/uploads/2016/11/EVF_Schematics-300x144.png)
Luckily I managed to get a service manual for the camera with a full schematic.
This unit takes a 5v input, as opposed to the 8-12v inputs on previous cameras, so watch out for this! There’s also no reverse polarity protection either.
![Pins](http://www.experimental-engineering.co.uk/wp-content/uploads/2016/11/2016-11-22_16-15-16_000771-300x225.jpg)
Making the iris marker vanish from the screen is easy, just put a solder bridge between pins 15 & 16 of the drive IC. The important pins on the interface connector are as follows:
Pin 3: GND
Pin 4: Video Input
Pin 5: Video GND
Pins 6: +5v Supply