Sharp ER-A450T Service Manual page 35

2) Functional description
Perform the following check for the standard RAM 256 KByte SRAM.
The memory contents should not be changed before and after the
check.
Perform the following processes for memory address to be checked
(1C0000H~1FFFFFH).
PASS1: Save memory data.
PASS2: Write data "0000H."
PASS3: Read and compare data "0000H," write data "5555H."
PASS4: Read and compare data "5555H," write data "AAAAH."
PASS5: Read and compare data "AAAAH."
PASS6: Restore the memory data.
If a compare error occurs in the check sequence PASS1-PASS6, an
error print is made. If no error occurs through all addresses, the check
ends normally.
The following address check is performed further.
Check point address =
1C0000H, 1C0001H, 1C0002H, 1C0004H
1C0008H, 1C0010H, 1C0020H, 1C0040H
1C0080H, 1C0100H, 1C0200H, 1C0400H
1C0800H, 1C1000H, 1C2000H, 1C4000H
1C8000H, 1D0000H, 1E0000H, 1F0000H
1 2
7-SEGMENT DISPLAY:
3) Check the following items:
Check the termination printout.
4) Test termination
The test terminates after printing the termination printout.
Termination printout:
Normal termination
Abnormal termination
Note: When an error occurs, the error print is performed and the
check is terminated. The error occurrence address is shown in
hexadecimal at positions shown with
[12] Standard ROM test
1) Key operation
130
CA/AT
2) Functional description
The sum check of the standard ROM (C00000H - C7FFFFH) is per-
formed. If the lower two digits of SUM is 10H, it is normal.
1 3
7-SEGMENT DISPLAY:
3) Check the following items:
Check the printout after the test.
0
120
Ex – – – – – 120
X = 1: Data check error
2: Address check error
.
0
4) Test termination
The test automatically terminates with the following termination mes-
sage.
Normal termination print
Error termination print
Note: " " means the ROM version number.
The underlined section (10 bytes) of code table is provided in
the ROM as standard and the table content is always printed.
The table position is the upper 10 digits of the ROM address.
The check sum correction address is the last address -0FH.
[13] A/D conversion test
1) Key operation
151 CA/AT
2) Contents
The digital conversion value of the input signal to the CPU A/D con-
vertor is displayed sequentially. The display channel changes at ap-
prox. 1 sec. intervals by a timer control and is displayed repeatedly.
Thermistor input
7-SEGMENT DISPLAY:
Vrf input: Vrf means the presumed voltage of VRF when VCC is
supposed to be +0.5V.
7-SEGMENT DISPLAY:
+24V input
7-SEGMENT DISPLAY:
Head input
7-SEGMENT DISPLAY:
Note: "XXXXX": The 10 bit data of the A/D convertor displayed in
decimal number.
Therefore, its connect may be 0000
3) Confirmation
Check the display content.
4) Termination
When the mode switch is set to any mode other than SRV mode, the
termination print is made and the test is terminated.
Test termination print
[14] Option RAM test
1) Key operation
200 CA/AT
JOB
RAM NO.
#NO.
200 Option RAM
5 – 5
ROM1 27040
E – – – –
ROM1 27040
1 5 1 1 XXXX
1 5 1 2 XXXX
1 5 1 3 XXXX
1 5 1 4 XXXX
1024.
151
Memory to be Address area to be
checked checked
ER-03RA 200000H 27FFFFH
130
130