Download Sharp AY-XP12DR-NC Service manual

MZ-80K
• Memory Circuit Block
AO
~ ____
A13
A15
~
\
A12
Chip select
A4
circuit
\
A2
Data selector
WR
Driver
RAM block
D7
ROM
DO
AO~A11
Block Diagram of Parts around Memory Circuit
Problem
1. Reproduced pictur shows
"panic".
Ch&ek Point
Check for the following:
ROM, IC46, CG, IC43
Address bus line; AO to A15 (IC44, IC45)
Data bus line; DO to D7 (IC36, IC37, IC50)
Control line; IC35
RAM (by using RAM checker*),
IC52, IC53, IC56
2. Error display or
misoperation is caused
as a resu It of program
execution.
RAM
3. Cursol disappears.
IC46,IC1
4. Returns to "MONITOR
SP-1 002."
RAM
5. Error is caused after
a long operation.
RAM
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