Atari 800XL Technical Service Data

SCHEMATIC NOTES
-w— Circuitry not used in some versions
-Circuitry used in some versions
e See parts list
+ Ground
Waveforms and voltages taken from ground, unless noted
otherwise.
Voltages, Waveforms and Logic probe readings taken with
computer turned On, no keys pressed, unless otherwise
noted.
Waveforms taken with triggered scope and Sweep/Time
switch in Calibrate position, scope input set for DC
coupling on 0 reference voltage waveforms. Switch to AC
input to view waveforms after DC reference is measured
when necessary. Each waveform Is 7 cm. width with DC
reference voltage given at the bottom line of each wave¬
form.
Time in /xsec. per cm, given with p-p reading at the end of
each waveform.
Item numbers in rectangles appear in the aiignment/ad-
justment instructions.
Supply voltages maintained as shown at input.
Voltages measured with digital meter, no signal.
Controls adjusted for normal operation.
Terminal identification may not be found on unit.
Capacitors are 50 volts or less, 5% unless noted.
Electrolytic capacitors are 50 volts or less, 20% unless
noted.
Resistors are ViW or less, 5% unless noted.
Value in ( ) used in some versions.
Measurements with switching as shown, unless noted.
Logic Probe Display
L= Low
H = High
P = Pulse
* = Open (No light On)

Atari 800XL Specifications

General

Manufacturer	Atari
Type	Home computer
Release year	1983
CPU	MOS Technology 6502C
RAM	64 KB
ROM	24 KB
Operating System	Atari OS
CPU Speed	1.79 MHz (NTSC) / 1.77 MHz (PAL)
Graphics	ANTIC and GTIA chips
Display resolution	160×192 to 320×192 pixels
Sound	POKEY chip
Storage	Cassette tape, floppy disk
Ports	Serial, parallel, monitor, joystick ports