Atari 2600 Field Service Manual page 111

2600A Gray
Bar Troubleshooting Procedure
(Rev isions 1
-1 3)
signal on t h e A20 1
side of R214, R215,
and R216?
I
f s there 3-5v P-P
signal on the A20 1
pin corresponding to
t h e resistor that had
I
no signal?
Yes
-
Check pullup resistor
R218, R219, or R220
on that line to insure
resistor is good and
one
side
is connected
to +5v.
Check
R214,
R15,
and
R216 with meter for
correct value.
Replace any defective
yes
{
Open between A2I 1
Repair
and that resistor.
L
I
P
Resistor
Replace
Defective?
Yes
Pg.
6-2
2600/2600A Domestic VCS