Can't increase contrast on PM4

[Hypoxicdreams]

Hello, the center button on the right doesn't work so i cannot increase the contrast on the monitor. It is a problem because i cannot read anying in the center of the screen, so i assume the contrast is low. Is there a way to control/adjust the menu options from a laptop?

Alternatively have any EE's discovered which component on the board goes bad for the center button malfunction? I dont see any visible burning or swollen caps.

[Carl Watts]

Clean the button contacts on the board with a cotton bud and some IPA or metalated spirits.

Clean up the rubber keypad with soapy water, dry and lightly clean the black carbon on it with a cotton bud and meths.

Look for corrosion on the board in the keypad area, its not a component failure its likely the copper track to the keypad has gone open at the nearby via.

If all the buttons work then there is a LCD contrast setting in the more options menu.

Screen contrast should be even across the LCD so if its not, the LCD could be stuffed as well.

If its a 1st Gen PM4, its pretty much had its day, if it needs too much spent on it get a new PM5.