Tandy Color Computer 3 TRS-80 User manual

TANDY®
Technician Series
Diagnostics Software
TANDY
Color Computer 3
Diagnostics Manual
NATIONIL TECHNICAL SUPPORT AND TRAINING

TECHNICIANSERIES DIAGNOSTICSOFTWARE
------------- TANDY COMPUTER PRODUCTS -------------
IMPORTANTNOTICE:
This diagnostic software and manual are written for TANDY®computer owners who
have a thorough understanding of electronics and computer circuitry. It is not
written at a comprehension level for the beginner.
Radio Shack® will not be liable for any damage caused or alleged to be caused
by the customer or any other person using this diagnostic software or manual to
repair, modify or alter any TANDY®computer in any manner.
,l
Many parts of the computer electronics are very sensitive and can be easily
damaged by improper servicing. We strongly suggest that for proper servicing,
the computer be returned to Radio Shack®.
While this diagnostic software and manual have been carefully prepared, Radio
Shack® will not be responsible for any errors or omissions and will not be
liable for damages resulting therefrom.
Opening the TANDY®computer housing, breaking the housing seal or altering or
modifying the computer will void the warranties given at time of purchase.

TECHNICIANSERIES DIAGNOSITIC SOFTWARE
------------- TANDY CDMPUTER PRDDUCTB -------------
COLORCOMPUTER-3Diagnostics Manual:
Cl987, Tandy Corporation
All Rights Reserved.
MEMC03Diagnostics Software:
Cl987, Tandy Corporation
All Rights Reserved.
IRQTST Diagnostics Software:
01987, Tandy Corporation
All Rights Reserved.
FRQTSTDiagnostics Software:
e1987, Tandy Corporation
All Rights Reserved.
COLORS64Diagnostics Software:
Cl987, Tandy Corporation
All Rights Reserved.
COC03VIDDiagnostics Software:
01987, Tandy Corporation
All Right Reserved.
CPUSPEEDDiagnostics Software:
C}987, Tandy Corporation
All Right Reserved.

TECHNICIANSERIES DIAGNOSITIC SOFTWARE
------------- TANDY COMPUTER PRODUCTS -------------
PSUEDODiagnostics Software:
Cl987, Tandy Corporation
All Rights Reserved.
PALTEST Diagnostics Software:
Cl987, Tandy Corporations
All Rights Reserved.
VPAGEDiagnostics Software:
Cl987, Tandy Corporation
All Rights Reserved.
MEMBANKDiagnostics Software:
Cl987, Tandy Corporations
All Rights Reserved.
VDGMODESDiagnostic Software:
Cl987, Tandy Corporations
All Rights Reserved.
Reproduction or use, without express written permission from Tandy
Corporation, of any portion of this manual is prohibited. While reasonable
efforts have been taken in the preparation of this manual to assure its
accuracy, Tandy Corporation assumes no liability resulting from any errors or
omissions in this manual, or from the use of the information obtained herein.
Please refer to the Software License on the ~ack cover of this manual for
limitations on use and reproduction of this Software package.

TECHNICIANSERIES
TANDY COMPUTER PRODUCTS
COLORCOMPUTER-3DIAGNOSTICS
Table of contents
INTRODUCTION•••.••••••••••...••••
COLORCOMPUTER-3DIAGNOSTICS•••••
MEMC03•••
IRQTST.•• ...............
............. .
FRQTST.•••.•.•••••••
COLORS64•••
COC03VID•••
CPUSPEED.·•••••.•••••
PSUEDO•••
PALTEST••
VPAGE•••
MEMBANK•••..•
VDGMODES.••
DIAGNOSTICSOFTWARE
1
3
4
4
s
6
7
7
8
8
9
9

TECHNICIANSERIES DIAGNOSTICSERIES
------------ TANDY COMPUTER PRODUCTS ------------
- INTRODUCTION-
The Color Computer-3 diagnostics were written with the purpose of helping
the technician diagnose the condition of the Tandy Color Computer-3. These
diagnostics will test features specific to the Color Computer-3. Some tests
may run on the Color Computer-2 or 1, but this is not recommended.
Below is a list of Color Computer-3 diagnostics, which test various items
such as interrupts, memory, and Color Video:
MEMC03/BIN
IRQTST/BIN
FRQTST/BIN
Tests all the memory of the Color Computer-3, up to 512k.
Color Computer Normal Interrupts test.
Color Computer Fast Interrupts test.
COLORS64/BIN - Displays all 64 Colors of the Advanced Color Video Chip.
COC03VID/BIN - Displays Alpha & Graphic modes. Also displays crosshatch.
CPUSPEED/BAS- Diagnostic for testing switching of the CPU clock speed.
PSUEDO/BAS - Tests
PALTEST/BAS - Tests
VPAGE/BAS - Tests
MEMBANK/BAS- Tests
VDGMODES/BAS- Tests
"false" colors (Produced by Artifacting circuitry).
the
the
the
the
Color Computer-3's Color Palette Registers.
Color Computer-3' s Video Paging Register.
Color Computer-3's MMUMemory Banking
VDGmodes of the Color Computer-3.
COLORCOMPUTER-3DIAGNOSTICS
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Register.

TECHNICIANSERIES DIAGNOSTICSERIES
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- MEMCOJ/BIN-
"MEMC03"is a diagnostic program which allows testing all of the RAMof the
Color Computer-3 (128k or 512k). The Memory Management (MMU)section of the
Advanced Color Video Chip (ACVC) allows the 6809 processor to access memory
outside of the normal 64k address range.
To load this memory diagnostic: type LOAD"MEMC03/BIN" and <ENTER).
To execute this diagnostic: type EXEC and press <ENTER>.
This diagnostic begins by showing a menu of selections available:
(1) = PASS MODE(Single/Continuous),
(2) • RAMTEST,
<3> • Exit to Basic.
When entering the menu, the MMUis tested to see
memory outside the normal 64k addressing scheme.
properly, then the menu will display "MMUGood".
properly, the menu will display "MMUBad" (Memory
ACVCchip may be faulty).
whether it will access
If the MMUis operating
If the MMUis not operating
or the MMUsection of the
Press <l> to toggle the pass mode and set it as single or continuous. This
flags the ram test whether it should test all memory once, or continuously.
Press <2> to invoke the memory test. The screen displays the pass number,
the test mode (write or verify), and the memory range being tested, with an
area on the video reserved for any errors that may occur during the memory
test. The memory range being tested, is displayed as two five digit
hexadecimal numbers which represent the beginning and ending addresses of the
memory range currently being tested.
The process of testing an eight kilobyte range (2000H) of memory involves:
Writing a modified address pattern to all segments of this memory range, then
verifying it from the minimum valid segment to segment seven, and displaying
any error messages. The minimum valid segment, is the segment where the
memory begins (128k machines= Segment-7, 512k machines= Segment-0).
Memory is tested in eight kilobyte (2000H) blocks as noted above, until the
end of memory (this is a pass). If the test is in the single pass mode, it
will exit to the menu. If in the continuous mode, the pass number is
incremented by one and all memory is tested again.
COLORCOMPUTER-3DIAGNOSTICS
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TECHNICIANSERIES DIAGNOSTICSERIES
------------- TANDY COMPUTER PRODUCTS -------------
(MEMC03/BIN - memory test, continued)
The<*> key may be pressed in order to freeze the memory test option of
"MEMC03", so that the error in format ion may be observed.
Press the <SPACE-BAR>to continue the memory test.
As the test proceeds, the address range being currently tested is displayed,
preceeded by the current test mode ("writing" or "verifying").
Press (BREAK>to exit the memory test and return to the menu.
At the menu, press <3> to exit to Basic.
- IRQTST/BIN & FRQTST/BIN -
IRQTST and FRQTST are designed to test the interrupts of the Color
Computer-3. Both of these tests are operated the same but IRQTST tests
the normal interrupts, and FRQTST tests the fast interrupts (FRQ).
IRQTST and FRQTST are machine language files, and must be loaded and then
executed. The proper loading and executing of the programs is shown below.
If testing normal interrupts, load IRQTST by typing:
type LOADM"IRQTST/BIN" and press <ENTER>.
If testing fast interrupts, load FRQTSTby typing:
type LOADM"FRQTST/BIN" and presf <ENTER).
To execute either test: type EXEC and press (ENTER>.
Both tests begin the process by displaying the interrupt to be tested then
waiting for the interrupt to occur. If the interrupt was received, the
program will display "Interrupt Received" followed by "Press Any Key To
·continue". If the interrupt didn't occur, then these last two messages will
not be displayed, but any key may still be pressed to continue and test the
next interrupt. If an interrupt is not received, then there may be a fault
in the ACVCor interrupt circuitry.
The interrupts tested include Timer, Horizontal Border, Vertical Border,
Serial, Keyboard, and Cartridge.
COLORCOMPUTER-3DIAGNOSTICS
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TECHNICIANSERIES DIAGNOSTICSERIES
------------- TANDY COMPUTER PRODUCTS -------------
- COLORS64/BIN-
COLORS64is a menu driven program, which allows the technician to ensure
that all 64 colors of the Advanced Color Video Chip (ACVC) are displayed.
To load COLORS64:
To execute it: type type LOAD"COLORS64/BIN" and press (ENTER). EXECand then press (ENTER>.
The program will then display the menu of tests available:
<l> = RBGmonitor test,
<2> = CMPmonitor test,
<3> = Exit to Basic.
This program uses interrupts, so run the interrupt tests (IRQTST and
FRQTST) to ensure that the interrupts are functioning properly.
A joystick must be plugged into the right joystick port for this test.
Pressing <1) invokes the RGBtest, which programs the color palette
registers for an RGBvideo monitor, then displays all 64 colors on the
screen in a grid pattern. Use the joystick to move the cursor over one of
the blocks in the grid. The background color of the screen will change to
the color of the block under the joystick cursor. Press the fire button of
the joystick to change the border color of the screen to the same as is
under the joystick cursor. Since this test loads the palettes with RGB
values, it is incompatible with composite video monitors.
Press <BREAK>to exit to the menu.
Pressing <2> invokes the CMPtest, which programs the color palette
registers for a composite video monitor, then displays all 64 colors on the
screen. These colors are displayed in rows. Using the joystick, move the
joystick cursor over one of these color blocks, and press the fire button of
the joystick to change the border color of the screen. Since this test
loads the palettes with composite values, it is incompatible with RGBvideo
monitors.
Press <BREAK)to exit to the menu.
At the menu press (3) exit to Basic.
COLORCOMPUTER-3DIAGNOSTICS
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TECHNICIANSERIES DIAGNOSTICSERIES
------------ TANDY COMPUTER PRODUCTS ------------
- COC03VID/B1N-
COC03VIDis designed to test the alpha and graphic modes of the Advanced
Color Video Chip (ACVC). Another feature of this test displays a cross
hatch pattern, which may be used to align monitors.
To load this diagnostic: type
To execute the test: type LOAD"COC03VID/B1N" and press
EXEC and press (ENTER).
The test begins with a menu of tests, as shown below:
(1) = ALPHATEST,
(2) = GRAPHICSTEST,
(3) = CROSSHATCH,
(4) • EXIT to Basic.
(ENTER>.
Pressing (1) invokes the Alpha Test to test the alpha modes of the Advanced
Color Video Chip (ACVC). This test fills the screen with different
characters that have different attributes to check all of the alpha modes
(Attributes affect the foreground and background colors of a character, and
can cause blinking and underline). The test will then cycle through all the
alpha modes (32, 40, 64, 80 characters/line) until the <BREAK>key is hit, at
which time it will exit the test and go back to the menu.
Pressing <2> invokes the Graphics mode test of the ACVCchip. This draws
color bars on the screen and then cycles through the different color graphics
modes. This test runs continuously, so press <BREAK>to return to the
menu.
Pressing <3> invokes the Crosshatch feature, which may be used for aligning
an RGBor composite monitor. Pressing the <SPACE-BAR>will toggle the
display between a crosshatch display (vertical & horizontal lines) and a dot
pattern display. Pressing <BREAK>will exit the test and return to the
menu.
At the menu press <4> exit to Basic.
COLORCOMPUTER-3DIAGNOSTICS
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TECHNICIANSERIES DIAGNOSTICSERIES
------------- TANDY COMPUTER PRODUCTS -------------
- CPUSPEED/BAS-
CPUSPEEDis a Basic program which allows the technician to see if the cpu
clock is changing speed properly.
To execute this diagnostic: type RUN"CPUSPEED/BAS"and press <ENTER>.
The test should then appear on the screen.
The test should begin by filling the screen with characters, followed by the
message "Press Any Key To Change Speed". The CPU speed (SLOW/FAST) is
display.ed at the top of the screen. By pressing a key to toggle between the
two speeds, there should be an observable difference in speed.
Press <Q> to exit this test.
- PSUEDO/BAS-
PSUEDOis a Basic program which allows checking of the artifacting circuitry
of the color computer. This circuity produces "false" colors when under
the highest color computer-2 graphics mode. Normally, this graphics mode
would produce only two colors (white and black or green and black), but
by drawing the pixels close together, the artifacting circuitry will send out
a color burst signal to simulate colors ("false" colors). Using this test
allows the technican to determine whether or not the artifacting circuitry
is working. This test is only valid on composite monitors, since "false"
colors are not produced on the RGBmonitors.
To execute this diagnostic: type RUN"PSUEDO/BAS" and press <ENTER>.
The test should then appear on the screen.
Press any key to begin the test. Four rectangles will be drawn on the
screen. The first (top) rectangle appears with a black center while the
fourth (bottom) rectangle appears all white. The second and third rectangles
will appear to have color on a composite monitor.
Press the <Q> key to exit this test and exit to Basic.
COLORCOMPUTER-3DIAGNOSTICS
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TECHNICIANSERIES DIAGNOSTICSERIES
------------- TANDY COMPUTER PRODUCTS -------------
- PALTEST/BAS-
PALTEST is a Basic program which tests the color palette registers of the
ACVCchip of the color computer-3.
To execute this diagnostic: type RUN"CPUSPEED/BAS"and press <ENTER).
The test should then appear on the screen.
Observe the 16 circles on the screen. Each of these represents a palette
register. The color inside of the circle is the current color of that pallet
register. These will change as each palette register is being tested.
The test terminates if an error occurs or when it .is completed. If an error
occured, it will report the palette# of the error, the data written, and the
data read. If no error occ ured, the test will display, "All Pallets OK!".
- VPAGE/BAS -
VPAGEis a Basic program which tests the Video Paging Register of the
Advanced Color Video Chip (ACVC). The program uses a machine language
routine to fill memory with a graphics pattern, then the basic program
initializes the video paging register for the test.
To execute this diagnostic: type RUN"VPAGE/BAS" and press (ENTER).
The test should then appear on the screen.
A pattern should appear on the screen when the test begins. As the program
tests the video paging register, it is repointed making the screen appear to
move left, up, and diagonally to the upper left corner. The pattern on the
screen should appear to move these three directions, if it doesn't then check
the ACVC. It's section that positions the video in memory may be faulty.
Since VPAGEis a continous test, press the <Q>key to exit to Basic.
COLORCOMPUTER-3DIAGNOSTICS
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TECHNICIANSERIES DIAGNOSTICSERIES
------------- TANDY COMPUTER PRODUCTS -------------
- MEMBANK/BAS-
MEMBANKis a Basic program which tests the MMUMemory Banking Register.
To execute this diagnostic: type RUN"MEMBANK/BAS"and press <ENTER>.
The test should then appear on the screen.
As this diagnostic begins, it should ask for the memory size of the computer
(Selection: <1>=128k, <2>=512k). The test will go through each segment
of memory writing a pattern (the Ascii value of the current segment).
The "physic a 1 address" displayed at the top of the screen, is the start of
the current screen displayed. The "physical address" contains five digits.
The first is the segment number, and the last four are a normal 64k address
represented in hexadecimal. The test will cycle through the segments, from
the minimum valid segment to segment seven. The minimum valid segment for a
128k machine will be segment-six, while it will be segment-zero for a 512k
machine (according to the memory size entered). If the memory segments are
not switching, then check the Advanced Video Color Chip. The MMUbanking
section of the "ACVC"may be faulty.
This test is continuous, so press <Q> to exit it.
- VDGMODES/BAS-
VDMODESis a Basic program which tests the VDGmodes of the Advanced Color
Chip (ACVC) in the Tandy Color Computer-3. These modes include Alpha,
Graphics, GM2, Inverse, and Upper/Lower Case.
To execute this diagnostic: type RUN"VDGMODES/BAS"and press <ENTER>.
The test should then appear on the screen.
This test test should automaticaly cylce through all the video modes shown
below. Below is a description of these modes.
Alpha • Alphanumeric text mode.
Graphics • Bit Plane (Graphics) mode.
GM2 = Will turn on Color Computer-3 Border, unless "INV" is set.
Inverse • Exchanges foreground and background colors of all characters.
Uppercase• Lowercase characters are displayed in reverse video.
Lowercase• Lowercase characters are displayed in true lower case.
Press <Q> To exit this test and return to Basic.
COLORCOMPUTER-3DIAGNOSTICS
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