Sharp ER-A440 Service Manual page 28

[12] Standard ROM test
1) Key operation
CA/AT
130
2) Functional description
Sum check of the standard ROM (C00000H - C7FFFFH) is per-
formed. If the lower two digits of SUM is 10H, it is normal.
7-SEGMENT DISPLAY:
3) Check the following items:
Check the printout after the test.
4) Test termination
The test automatically terminates with termination message.
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 a 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] Printer dot pulse width adjustment
1) Key operation
CA/AT
150
1 3 0
ROM1 27020
E – – – –
ROM1 27020
2) Functional description
Adujustment width of TPW at the test point TP1.
The pulse width of TPWW canw bwe adjusted using the 200K pot
VR1.
130
130
TPW=370±3(µs)
3) Check items
a) The pulse width of TPW must be adjusted to that at the above test
point TP1.
4) Test termination
Do the program reset.
[14] Option RAM test
1) Key operation
200
JOB
#NO.
200
2) Content
The following check are performed for the optional RAM.
The following process is performed for memory addresses to be
checked.
PASS1: memory data save
PASS2: Data "0000H" write
PASS3: Data "0000H" read and comparison, data "5555H" write
PASS4: Data "5555H" read and comparison, data "AAAAH" write
PASS5: Data "AAAAH" read and comparison
PASS6: Memory data restore
5 – 5
TP
VR1
CA/AT
Memory to be
RAM NO.
checked
Option RAM ER-03RA
GND
MAIN PWB
Address area to be
checked
200000H 27FFFFH