Repair By Parts Replacement; Does Not Operate At All With Power On - Star Micronics NX-1020 Technical Manual

4.

Repair by Parts Replacement

4-1. Does not Operate at All with Power on

START
+25V, +5V
are
supplied? *1
YES
RESET
signal becomes
HIGH? *2
YES
Crystal
waveform is
normal? *3
YES
ROM OE
signals become
LOW?
YES
Carriage motor abnormal.
Check operation.
END
NO
DC Power abnormal.
NO
Check RESET circuit;
replace parts.
NO
Check crystal circuit;
replace parts.
NO
1) Replace CPU or ROM.
2) Check relevant circuit.
*2 See (2) waveform in item 10 of Chapter 7.
*3 See (1) waveform in item 10 of Chapter 7.
*1 +25V Line
+5V Line
See 4-2. Power Supply
Circuit Abnormal.
+25V ± 5%
Between Pin 1 and Pin 2 of CN1
+5V ± 2.5%
Between Pin 4 and Pin 3 of CN1
– 65 –
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