Faulty Key Switch; Abnormal Printing Operation - Star Micronics LS-5 SERIES Technical Manual

2-12-4. Faulty Key Switch

Step
1 Check parts with different specifications for problems with
usage, defective installation, breakage, and deformation.
• Main parts to be checked:
(1) MCU PCB, (2) Console assy, (3) LVPS assy
2 (Check key switch on console assy)
Is the key switch functioning normally?
3 (Check voltage of key switch on console assy) *1
Is 5 VDC being supplied between P/J200-A1PIN
A12PIN?
4 (check key switch ON signal) *1
Are the following voltages being supplied when the key
switches are turned on?
• KEY (1) ON → 0 VDC between P/J200-B8PIN ↔ P/J200-A12PIN
• KEY (2) ON → 0 VDC between P/J200-A7PIN ↔ P/J200-A12PIN
• KEY (3) ON → 0 VDC between P/J200-B7PIN ↔ P/J200-A12PIN
• KEY (4) ON → 0 VDC between P/J200-A6PIN ↔ P/J200-A12PIN
• KEY (5) ON → 0 VDC between P/J200-B6PIN ↔ P/J200-A12PIN
• KEY (6) ON → 0 VDC between P/J200-A5PIN ↔ P/J200-A12PIN
• KEY (7) ON → 0 VDC between P/J200-B5PIN ↔ P/J200-A12PIN
• KEY (8) ON → 0 VDC between P/J200-A11PIN ↔ P/J200-A12PIN
*1: Check with the connector (P/J111) disconnected from the HVPS.

2-12-5. Abnormal Printing Operation

Step
1 Check parts with different specifications for problems with
usage, defective installation, breakage, and deformation.
• Main parts to be checked:
(1) MCU PCB
2 Is there no printing operation at all?
3 Is printing carried out normally in the Test Print mode?
4 Is the CPU reset during a printing operation?
5 (Check MCU PCB)
Does the problem occur after the MCU PCB has been replaced
with a normal one?
Check
↔
P/J200-
Check
– 97 –
TROUBLESHOOTING
Measure
YES
To step 2 Replace or
reinstall.
Replace MCU To step 3
PCB.
To step 4 To section 3-1
Replace MCU Replace console
PCB. assy.
Measure
YES
To step 2 Replace or
reinstall.
To step 3 To step 4
To step 5 Replace MCU
PCB.
To section 2-22 To step 5
Check main logic Processing
board. completed.
NO
NO