Bad key pad... or is it? (Acer AL2416W)

binba9

Honorable
Aug 10, 2013
4
0
10,510
Hi,
I've had this Acer AL2416W 24" LCD for years. Recently it wouldn't power off... and eventually it wouldn't power on.
The power-off part was odd, but I thought, the unit is 100% dead, gotta be the power supply. I was lucky to find an entire replacement PSU board for it from a nearby eBay seller, so I went for it. Another hint something unusual was going on was that once opening the unit, I couldn't find a single bad capacitor. Everything looked a-ok.

Since I already had the replacement PSU I went for it... and the monitor was still completely dead. I found the service manual online, which is more of a spec book than a troubleshooting tool, but it turns out that holding down the power button while connecting power resets the monitor's EPROM. Lo and behold - the unit is back online, crisp and sharp. I probably shouldn't have replacement the PSU at all...

However I'm back to square 1 - none of the buttons work (menu, auto adjust.), I can't even power the unit off. I'm therefore thoroughly confused - if the only thing that got the unit working was holding the power button, how come the power button doesn't work?

From a component replacement perspective, all that's left is the main (video) board, the key pad board, or the cable that connects them. Of course all of this might not matter much, since I can't find replacement parts for any of those 3 components anywhere (except one extremely shady Chinese web store).