Kurzweil K2600 Series, Service Manual

Page: 22 / 172

2-4
Diagnostics
Description of Tests
Description of Tests
LCD
This test writes a group of characters to the LCD and veri fi es that the same characters can be
read back again. The LCD Test includes four test phases that run automatically. The four steps
include the following:
1. Data test phase for the LCD character display memory
2. Address test phase for the LCD character display memory
3. Data test phase for the LCD graphics display memory
4. Address test phase for the LCD graphics display memory
The data test phase repeatedly writes the following 17-byte data pattern to the LCD:
0x00, 0xFF, 0x00, 0x0F, 0xF0, 0xCC, 0x33, 0xAA, 0x55, 0x11, 0xEE, 0x22, 0xDD, 0x44, 0xB,
0x88, 0x77
After the pattern is written, it is read back. If a difference is detected, the test fails.
The address test phase writes consecutive values to consecutive locations in the LCD. Then
these values are read back. If a difference is detected, the test fails.
A failure of this test indicates a problem with the LCD, Engine Board, connections between the
two boards or related circuitry.
Engine Blk (Engine Block)
This test computes an observed 32-bit check value of the setup area of the Flash ROMs (U4 and
U5) on the Engine Board. This value is then compared to the expected value, which is stored in
the
fl ash itself. If the values differ, an error is reported.
If this test fails, install the latest Operating System and run the test again.
A failure of this test indicates a problem with the microcontroller, Flash ROMs, or related
circuitry on the Engine Board.
Object Blk (Object Block)
This test computes an observed 32-bit check value of the setup area of the Flash ROMs (U4 and
U5) on the Engine Board. The value is then compared to the expected value, stored in the Flash
ROMs. If the values differ, the test fails.
If this test fails, install the latest Operating System and Objects and run the test again.
A failure of this test indicates a problem with the Flash ROMs or related circuitry on the Engine
Board.