One of my precious customers brought me three uknown state ZX spectrums for eventual fixing and maintenance.
This is part of my way to test and troubleshoot them!
I hope this video will help someone, and I hope you enjoy it!
I'm not a professional, so I'll admit that sometimes my repair attempts can make things worse. Please don't attempt to copy anything you see on this channel. If you try to mimic my methods and end up seeing the full invisible spectrum, call NASA, and good luck with that!