Hi @eternalgod
Here are the service manuals for two of the monitors that may help, at least how to open them. I couldn't find one for the Z30i model.
Unfortunately the control buttons aren't shown in the parts list, perhaps if they're on a board there may be a part number on it.
Not sure if HP is still the same but I had a HP monitor a few years back and the actuating pin of the button was broken so that when the button was pushed it didn't make contact with its associated tactile switch to operate it. (example only of what I mean)
What I did was to remove the button and use a small screwdriver to operate the switch to adjust the settings to the desired value and just left it on that setting, without replacing the broken button. Fortunately it only had to be done on two of the buttons as the others worked. Just an idea.
Z43 maintenance and service guide
Z32 maintenance and service guide
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