Posting this for posterity and the off chance that it might ever be helpful to someone else.
I have a resin 3D printer. Specifically, an Elegoo Mars (the OG, basic Mars). Luckily, I came late enough to the Mars party that mine particular printer was built on the Chitusystems v2 C-variant mainboard. That version-variant is important because it was implemented at the tail end of the original Mars production and is the same board that was used for the Mars 2 products.
The Elegoo Mars printer came from the factory with a RGB LCD installed on its print bed. This was primarily a cost-saving measure, which was great at the time because it made the printers cheap enough to produce for the home-consumer market. There are some big drawbacks, though: RGB LCDs filter out a lot of the ultraviolet light that cures the resin; and they degrade pretty quickly from UV exposure. Those two qualities combine to make the LCD a “consumable component” in the original design of this printer. The low UV-transmission requires longer exposure times to overcome, and the UV-sensitivity of the LCD gives it only ~200 hours of service before replacement is necessary.
Elegoo changed this part entirely for the Mars 2, swapping in a monochrome LCD specially designed for use in 3D printers. The UV-transmission of the mono LCD is greatly improved (lower exposure times), as is the durability (around 2,000 hours), as well a host of other performance improvements around contrast ratio, pixel-boundaries, build area size, and resolution.
With the same mainboard in (some of) the Mars 1 and (all of) the Mars 2 units, it is possible to replace the RGB LCD in the Mars with the mono LCD of the Mars 2, greatly improving the performance characteristics of the Mars printer. Now, that Mars printer is really long in the tooth, and there is no upgrade path to making it even remotely comparable to a newer, more modern printer - but mine has been a decent, reliable little workhorse of a printer with plenty of life left in it. There is no acceptable reason for this printer to become landfill just yet.
Chitusystems, the primary parts vendor for Elegoo, actually sells a 6.08-inch mono LCD upgrade kit for the Mars, and at a reasonable price. Installation is really straightforward: carefully remove the old LCD and the vat clamps, lay in the screen mounting bracket, replace the vat clamps, slot in the new LCD.
This also requires a firmware update so that the mainboard can correctly signal the new LCD how to operate. The Chitusystems product page links to a firmware download, but it turns out that their link is to the firmware of just one particular version of the LCD hardware.
I discovered this problem over the last few days while trying to get the upgraded LCD working. No matter what I tried, every single print resulted in the LCD simply not activating whatsoever, fully exposing the entire bottom surface of the resin vat regardless of the sliced file.
I suspected a firmware issue, but I figured I’d need to contact Chitu support to track down the issue. As someone who often works professionally in software and product support, I started gathering my problem documentation: images of the observed behavior, component model and serial numbers, evidence of installation process, firmware versioning, and demonstration of following the vendor’s upgrade instructions.
On visiting Chitu’s support page, I learned that there are multiple hardware versions of the mono LCD and that each one has its own firmware. This is not a detail exposed on the product page, and it’s not indicated in the upgrade instructions on the product page! Frustrating, yes, but 3D printing is a hobby for problem-solvers, often with very little in the way of official or universal processes - there is plenty of guidance, but we’re largely on our own to figure out what works with our local conditions.
Long story still rather long, once I got the firmware for the particular variant of the mono LCD I have (discernible by a model number stamped on the LCD ribbon cable), my test print lit up with the correct masking on the LCD! So there we go - turns out that the product page had incomplete details about the necessary firmware, but with a little bit of diligence and some sleuthing I was able to track down the needed information and keep my ancient little printer marginally relevant and useful for a little bit longer.