RAM
TEST
.
Purpose:
To test the 16K
RAM
chips for proper functioning.
Format: This
test
takes approximately 10 seconds during which the screen
is solid
black.
At the end of this time period, if the
test
has failed,
a
Failure Code number appears on the screen to signify which chip is
defective.
Swap out the chip corresponding to the Diagnostic Error Code
(Table 3-1).
If
this does not solve the problem,
swapout the chips U15,
U16,
U17, and U28 for
PCB
KA018087. For PCB KA020108, swapout
Al4, A15, A16 and A17.'
No Diagnostic Flowchart Entry Point
VERIFY
OS
ROM
0
Purpose: To
test
the
05
ROM
(U8)
for proper functioning.
0
Format:
If
error code 30 appears on the Error Summary (Figure 3-5) the
OS
ROM chip is defective. Replace the defective chip and restart the
test.
No Diagnostic Flowchart Entry Point
PORT
TEST
0
Purpose: This
test
checks the functions of the POKEY,
GTIA
and
associated PORT circuitry.
Format:
The test is done internally with failures appearing on the Error
Summary (Figure
3-5).
Diagnostic Flowchart Entry Point: (Refer
to
Table 3-1, Diagnostic Error codes).
TONE
TEST
0
Purpose:
To
check the audio generation section of the
POKEY
(U7).
0
Format:
The screen prints
at
the bottom which register is being tested
(Register 4,3,2,1).
A
series of eight tones will sound on each register. The
first two tones may be inaudible but you can hear the speaker click.
Diagnostic Flowchart Entry Point: Pg.
4-27.
CX5200 Field Service Manual 3-10
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