Service manual
Table Of Contents
- Revision Table
- Introduction
- Chapter 1
- Features and General Specifications
- Chapter 2
- Mechanism Configuration and Operating Principles
- Printer Mechanism Operating Principles
- Print mechanism unit
- Print head unit movement
- Wire movement when a single dot is printed
- Printing a character (9x9 font)
- Paper Feed Mechanism Unit
- Paper loading (semi-automatic loading)
- Paper feeding
- Ribbon Feed Mechanism Unit
- Ribbon feeding
- Detection Mechanism Unit
- Home position detection mechanism
- Paper detection mechanism
- Paper roll near-end detection mechanism (optional)
- Auto-cutter mechanism
- Ribbon Switch Mechanism Unit
- Electrical Circuitry Operating Principles
- Principles of Operation
- Printer Mechanism Driver Circuits
- Printer Mechanism Operating Principles
- Chapter 3
- Handling and Maintenance
- Chapter 4
- Troubleshooting
- Chapter 5
- Disassembly, Assembly, and Adjustment
- Small Part Specifications
- Disassembly
- Sub-assembly A
- Main Assembly 1
- Main Assembly 2
- Main Assembly 3
- Main Assembly 4
- Main Assembly 5
- Main Assembly 6
- Main Assembly 7
- Main Assembly 8
- Main Assembly 9
- Main Assembly 10
- Main Assembly 11
- Main Assembly 12
- Main Assembly 13
- Main assembly 14
- Main Assembly 15
- Main Assembly 16
- Main Assembly 17
- Main Assembly 1 (Case Unit)
- Main Assembly 2 (Case Unit)
- Main Assembly 3 (Case Unit)
- Main Assembly 4 (Case Unit)
- Main Assembly 5 (Case Unit)
- Main Assembly 6 (Case Unit)
- Main Assembly 7 (Case Unit)
- Main Assembly 8 (Case Unit)
- Main Assembly 9 (Case Unit)
- Main Assembly 10 (Case Unit)
- Main Assembly 11 (Case Unit)
- Main Assembly 12 (Case Unit)
- Adjustment
- Appendix
- Appendix
- Addendum 1
- Main Circuit Board Types and Maintenance
- Addendum 2
- Lower Plate Change and ROM Spacer Abolition
- Addendum 3
- Auto-Cutter Release Tab Change

Rev. B Mechanism Configuration and Operating Principles 2-21
TM-U200 Series (Type B) Service Manual
Confidential
RAM (CPU internal 2K bit)
RAM is used as temporary storage for the following:
❏
Data received from the interface (receive buffer)
❏
Pattern data to be printed by the print head (printer buffer)
❏
Data used by the CPU (U5) during processing (flags, pointers, etc.).
Operation panel
The operation panel is located on the main circuit board and has 3 LEDs (
POWER
,
ERROR
, and
PAPER OUT
) and 1 switch (
FEED
). The
POWER
LED is driven at the same time as +5 V is
supplied by the power supply circuit. The
ERROR
and
PAPER OUT
LEDs are driven by U5.
Switch detection is also executed by the U5.
Various detector circuits
When the printer detects paper, the paper detector at the paper inlet turns the input signal to the
CPU (U5) LOW. This detector also functions as the semi-automatic loading detector.
A home position sensor is provided to detect the print head position. The input signal to the
CPU (U5) becomes LOW when home position is detected.
Figure 2-21 Operation panel circuit
P82
C17
R55
Q35 Q36
R56
R41
R54
R15
SW2
1 1 1
222
(PAPER)
D12
(ERROR)
D11
(POWER)
D13
+5V
U5
32 PF SW
1 ELED/DSW9
80 PLED/DSW0
P57/T03
P56/INT3/TI2
GND