Z110BT Home and Mode Buttons don't work

[Clash1980]

Hi,  I just got a used 110.  My first AVIC.  

The unit seems to work fine except the MODE and HOME buttons don't do anything?

I got the service manual and followed the schematic to test the actual keyboard and find that mode, home, and voice buttons all output on KEY0 of the keyboard connector.  I tested those buttons with an ohm meter and they register the correct values out to the touch screen board with the ribbon connected, so I know the buttons and the ribbon are okay (mode=0, voice=1.2k, home=3.6k).  So now I wonder why they don't work?  I haven't fully tested the voice button since I don't have a microphone (yet).  When I press it, there is no change on the screen.

If anyone has any suggestions of what to try next, it would be really appreciated.  Maybe the keyboard really is bad?  The part tested is CWN3988.

Thanks for this site, it's great!

 

[Clash1980]

I got this fixed with the help of the service manual.  The schematic showed there should be a connection on the monitor pcb.  That connection was open.  Basically, the pcb had a bad trace on it.  There was a corroded via so soldering a jumper wire between the open fixed it.

Unfortunately I already ordered a replacement ribbon cable as I thought that might have been the issue.  If anyone needs a replacement ribbon cable (the one that goes between the main unit and the tilting screen, let me know!