Casio DR-220TA Service Manual

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4. TROUBLESHOOTING
Trouble
1) Does not work
at all.
2) No display.
3) No print.
4) Poor display.
5) Poor printing
• Motor does
not stop.
• Missing of
digits
Cause
• Defective power transformer
• Defective LSI
• No voltage at VF1, VF2
• No digit signal or no segment
signal
• Defective display tube
• Poor voltage VM
• Defective motor
• Defective LSI
• Short or open circuits
between digit signals and
segment signals.
• Defective display tube
• Timing signal is bad.
• Defective printer magnet
Checkpoint
Secondary voltage of
transformer
Waveforms of each pin
VF1, VF2
Signal D1 ~
S1 ~
Between LSI and
display tube
Note
VDD, VSS, VM, VF1, and
VF2 are OK?
Check the pulse signals
from LSI.
If VF1, VF2, Digit and
Segment signals are OK.
VM=11V (while printing)
Check detector of printer
block and timing signal.
• Refer to the printer service manual published separately.

Casio DR-220TA Specifications

General

Brand	Casio
Model	DR-220TA
Category	Calculator
Language	English