B&W CRT Monitor from a Karaoke Machine part3

I finally got around to do a ruff build of the setup. I had no idea the Raspberry Pi Zero W has a CVBS output, kinda wish I knew that before buying a HDMI2RCA Adapter.

With a fresh SD card with Raspberry Pi OS Lite written to it I created the ssh file and the wpa_supplicant.conf file for my WiFi connection. I then had to ssh into the Pi and edit the config.txt file and made these changes.


These settings made the CVBS or Composite Video work with the B&W Display. Since I am in North America I have a NTSC video format. I made sure it uses the 4:3 Aspect ration and turned off Color Burst since after all it’s Black and White. I also disabled the Rainbow Splash screen and for good measure I made sure the HDMI force hotplug was hashed out. Saved the file and rebooted to a scrambled Output so I had to fiddle with the Pots to lock the signal an adjust the height and width.

I made a little board that breaks out the Micro USB to a standard USB2.0 Port and added the Filtering for the Audio. Since the Raspberry Pi doesn’t have a true Audio DAC you can still get Audio from using a couple of PWM pins. Since there have been major changes in Raspian since some one figured out how to do this on a Pi Zero this is what is needed now in the config.txt file.


After rebooting you should be able to run Alsamixer and control the Volume. If anything leave the Volume low and use a external Amplifier.

RS-232 was easy. By default the Pi uses /dev/serial1 as the TTL RX/TX. Just use a TTL to Serial Adapter that works with 3.3V such as the Max3232 and it’s good to go. From there its just setting up Minicom to use /dev/serial1 or just define it when using Screen.

I’ve been running this all day and it seems sound. Next weekend I’ll work on the case for it and do a photoshoot.

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