Agilent 54622a PulseWidth and ModeCoupling buttons not working

[BC7333]

Hi all!
have this used osci, self-tests and self calibration worked fine, battery ok and replaced carbon rubber conductors on several keypads, all work fine now except for PulseWidth trig and ModeCoupling.  When powering on the LED for PulseWidth flashes so led is ok.  Reset to default works fine. Also tried direct contacts with graphite leads on the circuit board without the rubber buttons all work fine except these two.  Did some continuity checking and tested transistors and other components, all seems fine.  Unfortunately can't find a schematic anywhere.  Anyone know if a schematic is available somewhere or has one?  If not, anyone have an idea where to continue looking for the problem?  Any good vintage parts sources y'all know of? Would like to try another keypad board to see if that resolves the issue. 

Kind thanks for any assist!
Brian

[BC7333]

Here are some pics

Pulse Width trig S35/S36  Mode Coupling S15/S16