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Texas Instruments PC-800 Printer (EVT)

Date of introduction:  Never
 (Announced: May 1982)
Display technology:  
New price:  MSRP: $185.00 Display size:  
Size:  6.5" x 10.0" x 2.7"
 165 x 254 x 68 mm3
Printer technology:   Thermal
Weight:  50.8 ounces, 1,442 grams Serial No:  
Batteries:   Date of manufacture:  wk 14 year 1982
AC-Adapter:  120 V or 240 V or DC Origin of manufacture:  USA (ATA)
Precision:   Integrated circuits:  CD8000B, CD8020A, SN77203,
 LM393P, 3xULN2002A
Memories:      
Program steps:   Courtesy of:  Joerg Woerner

The PC-800 Printer is a dot-matrix thermal printer designed for use with the TI-88 Programmable. It connects to the TI-88 through a 2-pin Peripheral I/O connector. A second Peripheral I/O connector on the back of the PC-800 allows to connect another device like the CA-800 Cassette Interface to the TI-88.

Please notice that this PC-800 EVT (Engineering Validation Test) still uses a prototype housing with unfinished surfaces and a different color schema for the buttons and switches.

Printer Control of TI-88 Programmable:

Print the contents of the display at any time
Print alphanumeric prompts, operating instructions, and messages
Print program input and output
Print the contents of program or data memory
Print all labels used in a program
Print OP code and flag definitions, calculator settings, nd alpha entry positions
Print tracings of keyboard calculations and program execution showing each function executed with its result

The PC-800 printer operates by moving an electronic print-head across a special heat-sensitive paper. Characters are formed on the paper from small dots produced by heated elements on the print-head.

Dismantling this PC-800 from an early EVT (Engineering Validation Test) manufactured by Texas Instruments around April 1982 in their Abilene, Texas facility, reveals a design with a complexity similar to the PC-100C and PC-200 printers utilizing two microcontrollers CD8000 and CD8020, a SN77203 Voltage Controller chip and three ULN2002A arrays with seven NPN Darlington transistors, each.

The two microcontrollers with Custom Design Software CD8000 Revision A and CD 8020 Revision A are not yet discovered, but we noticed that both components still use prototype chip packages. The SN77203 is known from the TI-88 Schematics Diagram, it converts a single-cell battery (1.2 Volts - 1.5 Volts) to two independent power supplies, one adjustable for the LC-Display through a Serial I/O pin and one fixed for the main electronics.

Please notice the missing diodes with this PC-800 Printer compared to a PC-800 PVT (Production Validation Test) manufactured a few month later in August 1982. Learn more about similar modifications discovered with the TI-88 PVT 2 (Production Validation Test 2).

The PC-800 Printer can be operated by either an integrated AC adapter with 120/240 Volts (fixe-mounted power cord) or an external DC adapter (connector on the rear next to the two Peripheral I/O connectors.


Printer paper:

The thermal paper used with this printer (Kanzaki Paper KPB-53Z-48 1.97" wide and 85 Feet length) was discontinued long time ago.

 

Don't connect a CA-800 Cassette Interface or a PC-800 Printer to TI-88 calculators without the Diode-Modification!


 

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If you have additions to the above article please email: joerg@datamath.org.

Joerg Woerner, October 14, 2019. No reprints without written permission.