Service manual

3. DIAGNOSTIC CHECK
Service Manual BSM-4100 3.21
CRTC Check Menu Items The CRTC check menu items check the function of the display control block,
including the LCD unit. These check results cannot be recognized by the host
CPU, so you must judge the result.
If an error is found, the MAIN board will be faulty.
GRAPHIC MEMORY Check and CHARACTER MEMORY Check
These items check the Graphic RAM and Character RAM on the MAIN board for
the waveform display or character display by the write/read check technique. If an
error is detected, the error bank, address and data are displayed as a table.
Procedure to Start the GRAPHIC MEMORY Check and CHARACTER
MEMORY Check Program
1. To select the GRAPHIC MEMORY Check or CHARACTER MEMORY
Check, touch the “GRAPHIC MEMORY CHECK” or “CHARACTER
MEMORY CHECK” key.
The “START” key is highlighted to indicate the process of checking.
2. If the check program finds an error, it displays the address (and block bank),
write data and read data as shown in the above table.
3. To stop the check temporarily, touch the “STOP” key. The “START” key name
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.