Electronics are not immortal as we all know well. Sooner or later, a problem will arise that is not tied to a specific failure but to something as natural as the passage of time. Old CRT televisions are no exception, especially those titans with round tubes like the RCA CTC-16 from the 60s that ended up in the hands of shango066 on YouTube. This television often develops "cataracts", the classic deterioration of the adhesive that holds the safety lens in its ideal position, and the process of removing it requires some care…
A failure we are seeing in the first generations of LCD panels is based on a chemical reaction that produces very unpleasant patterns and textures. Known as "vinegar syndrome", this reaction is autocatalytic, and the damage it causes is irreversible. The only way to correct its effects is to completely replace the polarizer, a complex process, although not impossible.
But what about CRT tubes? Although the "vinegar syndrome" does not affect them, they can develop an equivalent in the form of cataracts. Over the decades, (and the intervention of factors such as contraction, expansion, humidity, and dust), the adhesive that keeps the safety lens fixed to the front of the tube begins to fail. shango066 on YouTube has in his possession a classic RCA CTC-16 television from the 60s that suffers from cataracts, and decided to share the process to eliminate them:
How to remove cataracts from CRT tubes
shango066 is no amateur when it comes to exploring, repairing, and restoring old televisions. In fact, one of the first things he explains is the difference between Zenith and RCA tubes when it comes to removing their cataracts. On Zenith tubes, direct heat is not recommended; instead, you have to separate the lens from the tube with a hotwire, or let it cook in the sun for a good while before using the wire. In contrast, for this RCA tube, shango066 took advantage of one of the hottest days of the year, left the tube in the sun with a black cover, and then continued with a heat gun.
When it reaches the correct temperature, you barely need to pry on the lens, and it should come off without too much headache. Of course, the nature of CRT tubes means that the overall risk is not zero... but removing the old adhesive is very satisfying. From this point, the user has two options: Remove the lens permanently, or reseal it with spacers and silicone. Some enthusiasts argue that the lens is there to prevent impacts from the outside, not to protect the user in case of implosion. Removing the lens also helps improve (a little) the image quality, but its presence in televisions was not a mere whim...
