S*T J
July 1981
12
ATARI
ASTERDIDS 11
11
TROUBLESHOOTING TIPS
Y (vertlcaQ output missing pieces
~
'-v'7
Place game in Self-Test On the display the lines
running left to right are good, but the lines
running from top to bottom are broken up. The
problem is in your Y-output circuit. Could be a
bad 0-to-A converter 811 or Y-position counters
J9, H9, F9.
X (horizontal) output missing pieces
Asteroids:
one side brighter than the other
Q
Problem in Scale 0-3 circuit Could be bad Latch
K7 or wrong resistor value in your Scale 0-3
resistor network. Correct values are R35 1.2K,
R36 2.2K, R37 4.7K, R38 1 OK; or 07, 09 bad.
Letters and asteroids
shaky or shadowed
,\d\,
In Self-Test, the lines running left to right are
broken up, but the lines running top to bottom
are good. The problem is in your X-output circuit.
Could be a bad D11 (AD561) or bad X-position
counters E9, 09, C9.
Test mode ok,
but won't go Into game play.
Problem could be in the NMI circuit to the
Processor Pin 6. In Self-Test Pin 6 of MPU
should be high. In game play, should be high
with low pulses. If game won't go into play
mode, problem probably is C5 counter or L 1 0
input multiplexer.
Bad graphics
(alphanumerics, ships, rocks)
,@
Place game into Self-Test Look at lines. If lines
running top to bottom are bad, look at your Y-
output circuit and position counters 811, H9,
J9, F9. If lines r.unning left to right are bad, you
have an X-output or position-counter problem
011, E9, 09, C9.
" -
Problem could be bad Op-Amp C12 or A 12. If
either Op-Amps are N94 7s, replace with TL082.
Problem could also be bad or missing inductors
L 14, L 15 (90 uH).
Bad ship fire sound
Check power supplies + 12, +5 for ripple. If
power supplies okay, could be bad M10 or 01,
05.
Oversized characters
letters too big
AA
Problem in your timer circuit could be bad
M7, M6, E7.
leset problem
where game won't go Into game
play but goes Into Self-Test
Bad graphics in Self-Test
If pin 40 of MPU is pulsing, then put the game
into Self-Test If it stops pulsing and the
graphics are bad, problem probably is in state
machine PROM CB.