Shimadzu SPD-20A User Manual

228-90095F
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8.3 Problems with electrical circuits and points to check
Points to check on the SPD20-MAIN and SPD20-PWR (power supply) circuit
boards are summarized in the tables below. Please use them when experiencing
problems with printed circuit boards.
8.3.1 SPD20-MAIN circuit board
8.3.1.1 Reference voltages
Item Allowable range Points to check
±A5V
+5V: +5 ±0.5V across P2-P40
-5V: -5 ±0.5V across P2-P41
M10, M11, J19
±12V
→ ±5V
D5V
+5 ±0.5V across P2-M1
M7, L1, C12, C21
3.3V +3.3V ±0.3V across P2-P4 M5, C9, C17
24V +26V ±5.0V across P2-P3 M2, M4, M6, M7, M8, J19
18V +18V ±2V across P2-C3 J19
8.3.1.2 Firmware read circuits
Item Points to check
Failed to read
J14, J15, J16, M14, M19. M21,
M32, X1
M21
(CPLD)
writing
8.3.1.3 Instrument startup circuits
Item Points to check
Instrument won’t start M18, M19, M25, M29, X1
Reset, NMI, CPU,
RAM
Messages not displayed in VFD display area. Key
input not possible. LED display malfunctioning.
M12, M17, M21, J9, F4 --
F13
Key display
interface
8.3.1.4 PWR PCB interface circuit
Item Points to check
D2 or W lamp does not turn on/off M12, M13, M19, J19
D2 or W lamp current values are abnormal
J19, M19, R32, R33, R39, D5 --
D8
Hg lamp does not turn on/off M1, J1, Q1, C3
J2 connector output voltage for PWR PCB not
changing
J19, M12, M19

Shimadzu SPD-20A Specifications

General

Brand	Shimadzu
Model	SPD-20A
Category	Security Sensors
Language	English