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.
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.
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
While I’m waiting for the fan controllers to arrive for the new cooling fans, I figured I’d get them fitted into the cases of the supplies & just have them run at minimum speed for now.
After removing the original small fan, I cut a larger square hole in the panel to fit the 60mm version. These fans only fit with some minor adjustment to the top & bottom mouldings, but the look isn’t too bad once the covers are back on. The wiring is routed through a small hole next to the fan itself.
I’ve also upgraded on the fans again – these are PFC0612DE, with a higher airflow of ~70CFM at 12,000RPM.
To get the fans to run at minimum speed, the PWM control wire is connected directly to GND.
My other monitors are a different model, and have a slightly different main PCB inside, but the process is mostly the same for converting these to 12v supply.
In this monitor type, there is only a single board, with all the PSU & logic, instead of separate boards for each function.
This monitor is slightly different in it’s power supply layout. The mains supply provides only a single 12v rail, which is then stepped down by a switching converter to 5v, then by smaller linear regulators to 3.3v & 1.8v for the logic. This makes my life easier since I don’t have to worry about any power conversion at all.
Here’s the backside of the PCB, the mains PSU section is in the centre.
Here’s the pair of 12v supply wires soldered onto the main board, onto the common GND connection on the left, and the main +12v rail on the right. I’ve not bothered with colour coding the wiring here, just used whatever I had to hand that was heavy enough to cope with a couple amps.
A small mod later with a cone drill & the 12v input socket is mounted in the LCD frame.
Some light removal of plastic & the back cover fits back on. Current draw at 13.8v is ~2A.