Is the JVC TM-13U any good?

[dubc]

For testing, the 240p test suite is the most common tool via gaming consoles.
http://junkerhq.net/xrgb/index.php/240p_test_suite

Calibration is a different beast based on the set and issues that need to be resolved. Search online for the service manual for your model number.

I’d also recommend reading through RetroRGB.com. It’s a great resource with a lot of useful information.
https://www.retrorgb.com/

A lot of good info in the original post of the retro AV thread as well

Retro AV |OT| RGB, CRTs, Upscalers, and more

Welcome to the Retro AV thread, here to help you get the best picture quality out of your retro consoles. Using a CRT? A framemeister to a modern LCD? Or maybe an OSSC? We’ll do our best to help you get the best image quality out of how ever you play your classic systems. Quick note I will be updating this OT in the coming days but I wanted to get something up quickly. I figured it would be good to start with a crash course on Analog video Signals. I plan on adding sections for Upscalers (fra…