Fixing the menu buttons on the front of a monitor...

General Questions
#1

I have a ViewSonic A57f. On the front of the monitor are 4 buttons:

“1” (or Menu/Page)
“Down”
“Up”
“2” (or Select/Exit)

The 1 and the Up arrow buttons work, but the Down and the 2 buttons do not. This is keeping me from adjusting the screen proportions or position, so I am stuck with a perfectly centered 1280x1024 view with about a half of an inch of nothing on all 4 sides.

It’s especially weird since the working/non-working buttons alternate, as in: Working, Non-Working, Working, Non-Working

Anybody have any experience in fixing these types of buttons, or know what could be causing it? Any suggestions?

Thanks!

#2

There is usually some sort of pressure sensitive contact swich behind the button. If there is no springy “click” or give to the button the switch may be defective.

If the buttons are working and not working per your description a likely possibility is that the buttons will only work as you switch between modes and you are not selecting the appropriate mode for the button to be active.

Are you sure this is not the A75F?

Here is a software calibration tool for your model.

#3

http://www.viewsonic.com/support/calibration.htm

#4

Actually, what I meant by “working/non-working” was that, going left-to-right on the front of the monitor, the 1st button works, the 2nd one doesn’t, the 3rd one does and the 4th one doesn’t.

The buttons should work in all modes. I have tested each mode, including the non-Windows bootup/BIOS modes (plain text).

The 2nd and 4th buttons simply do not work.

I talked to ViewSonic, but I do not want to pay the ~$30 to ship it to them so they can keep it for a month while they work on it (I have had the monitor for almost 2 years)

#5

The 4 buttons seem to be electrically arranged in a matrix like this:


A-1-2
  | |
B-3-4
  | |
  C D

Pressing button 3 connects line B to line C, for instance. The microcontroller alternately puts a voltage on line A and B, and looks if it comes out at C or D. If one output or input is dead, the whole corresponding row or column of buttons doesn’t work.

Most likely it is a defective microcontroller. The small probability of the fault being somewhere else and that you can fix it by yourself isn’t worth taking the trouble to check out.