Service manual

3. DIAGNOSTIC CHECK
3.42 Service Manual BSM-4100
DPU COM RAM Check
This item checks the dual port RAM for communication between the host CPU on
the MAIN board and CPU on the DPU board. The check method is the same as the
system RAM check. The check program indicates the address, write data and read
data if an error is detected.
This RAM is located on the DPU board. Therefore if the error is detected, the DPU
board will be faulty.
Procedure to Start, Stop, and Exit the DPU COM RAM Check Program
1. To select COM RAM Check, touch the “COM RAM CHECK” key at the DPU
CHECK column. The check program automatically starts.
The “START” key is highlighted to indicate that checking is being done.
2. If the check program finds an error, it displays the DPU part, address, write data
and read data as shown in the above table.
3. To stop the check temporarily, touch the “STOP” key. The highlighted
“START” key changes to normal and the “STOP” key is highlighted.
To continue the check, touch the “START” key again.
4. To return to the MANUAL CHECK MENU screen, touch the “RETURN” key.