Figure 2-28 Disassembly of CRT screen filter
1.4.8Disassembly of the keyboard, trackball and buzzer
1.  Remove   the   two   keyboard   silicone   rubber   caps,   and   then   remove   2   M3×6 
screws fixing the keyboard upper cover; 
Figure 2-29 Remove the silicone rubber caps 
DP-3300/DP-3200 Service Manual(V1.1) 2-21