The Speaker Company TTP 248M service manual TTP-248M Bar Code Printer Reset Circuit

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TTP-248M Bar Code Printer

Service Manual

3.3 Reset Circuit

VCC

VCCL

 

VCC

 

3

R3

VDD

3. 0K

4

 

5

R2

C77

3. 4K

C78

0. 1uF 0. 1uF

U10

VCC3

/RST

VCC5

GND

VCCA

LTC1 72 8

R130

10 K

1 RESET

2

GND

GND GND

GND

Fig. 3.3 Reset Circuit

This is the reset circuit. The LTC1728IC detects three kinds of DC Voltage (5V, 3V and 1.9V).

VCC3 (VCC, DC3V) input threshold is 3.086 VCC5 (VDD, DC5V) threshold is 4.675.

R2

VCCA ( R1+R3 ×VCCL, DC1V ) is 1.000

RST is reasserted whenever any one of the Vcc inputs drops below its predetermined threshold and remains asserted until 200ms after all of the Vcc inputs are above their thresholds.

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Contents TTP 248M Table of Content TTP-248M Bar Code PrinterTTP-248M Bar Code Printer Foundamentals about the System Printer OverviewTTP-248M Bar Code Printer Pinter Specification SpecificationCommunication Interface Available Bar Codes Text Specification File Head of Font Fixed 32bytes BF3~4 VF3~4 Specification Types of PaperTTP-248M Bar Code Printer Ribbon Specification Circuit Description MCUMCU MCU PIN Description Page Page Page Page Page Page Page Page TTP-248M Bar Code Printer Reset Circuit Reset CircuitTTP-248M Bar Code Printer Memory System Etro N TechDecoder Circuits Memory Address MapUse by CPU Area Internal I/O Sdram TTP-248M Bar Code Printer Firmware Address Map TTP-248M Bar Code Printer Power Down Sensor VCCTTP-248M Bar Code Printer Print Head GNDMotor System Circuit Stepping Motor PatternTTP-248M Bar Code Printer Sensor Circuits Ribbon Near End Sensor10 Black mark/ Gap Sensor Circuit Peel-off Sensor 11 Peel-off Sensor Circuit Case Sensor Serial Port Circuit GND VDDParallel Port Circuit VDDTTP-248M Bar Code Printer Cutter Drive System 17 Cutter Drive CircuitTTP-248M Bar Code Printer PIN Switch Circuits Connector Circuits21 Memory Card Connector 23 Stepping Motor Connector TTP-248M Bar Code Printer Optional Items Circuits Optional Item---BuzzerMachanism Remove the Covers and LCD PanelLoosen the three screws on Top Left Side Cover Screw LCD Panel Lower Front Cover TTP-248M Bar Code Printer Replacing the Mainboard TTP-248M Bar Code Printer Replacing the Power Supply Unit Belt Ring of Label Rewind Spindle Remove the E-ring of pulley. And then, remove the pulley TTP-248M Bar Code Printer TTP-248M Bar Code Printer Replacing Ribbon Supply Spindle TTP-248M Bar Code Printer TTP-248M Bar Code Printer Replacing Label Supply Spindle TTP-248M Bar Code Printer TTP-248M Bar Code Printer Replacing Label Rewind Spindle TTP-248M Bar Code Printer TTP-248M Bar Code Printer Replacing Platen Remove the Platen and Left Shaft Bearing TTP-248M Bar Code Printer Replacing Motor TTP-248M Bar Code Printer TTP-248M Bar Code Printer Replacing Print Head Remove the 2 screws these are on the TPH switch plate Remove A.B.C.D in order Loosen M4 screw, knob E and F TTP-248M Bar Code Printer Replacing Gap/Black Mark Sensor TTP-248M Bar Code Printer Reassemble in the reverse procedures after replacing Curly plastic pipe Screws Troubleshooting TroubleshootingCalibrate Gap/Black Mark Sensor Flash / DramDiagnosis Operation Procedure TTP-248M Bar Code Printer Self-testDram Clear TTP-248M Bar Code Printer Cleaning Print Head Update History No.35, Sec , Ligong 1st Rd., Wujie Township