I got a Viewsonic Optiquest Q71 (date on the back suggests it's from around 2003), and when I fired it up for testing I was pleased to find out that it has a very sharp image with vibrant colors, so it seems what the original owner said about it having very little use is true.

However, when trying to adjust the image via the OSD I encountered some issues. The button bar is very similar to other Viewsonics from that time:

[1] [DOWN] [UP] [2] - [LED] [ON/OFF]

The problem is that the buttons exhibit a strange behavior. In particular the [UP] button sometimes works as if it was [1] and goes back to the previous menu instead of moving up through the menu or increasing brightness/contrast for example. But this is not consistent, as sometimes it works as expected: I press [UP] a few times to increase brightness, it works on the first two presses but on the third it exits the menu.

The other buttons in general do what they're supposed to do, but sometimes I have to press them twice two get them to work, for example to turn on/off the monitor, and in a couple of instances the [1] button made a "VOLUME" bar pop up instead of the regular OSD (weird, as this monitor does not have integrated speakers).

The buttons are on a small PCB, to get access to it I had to pretty much disassemble the whole monitor, so I took the opportunity to thoroughly clean it as it was very dirty and smelly (came from a smoker's home - ugh). I could not find any visible issues with the buttons, and I also replaced the capacitors and reflowed dodgy looking joints on both the main and neck board PCBs.

Upon reassembling it, the same behavior persists so I'm kind of stumped, and it's a shame given the good condition of the tube. I'm open to suggestions, also I've been unable to determine how to access the service menu on this thing (if it's even possible). I dread having to open the monitor again, but can do so if someone has a clue or needs a specific picture to troubleshoot.