Service manual

• Memory Circuit Block
AO ~ ____ A13
~
Data selector
RAM block
WR
D7
DO
Chip select
circuit
ROM
AO~A11
Driver
Block Diagram of Parts around Memory Circuit
Problem
Ch&ek Point
1.
Reproduced pictur shows
Check for the following:
"panic".
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
RAM
misoperation is caused
as a resu It of program
execution.
3.
Cursol disappears.
IC46,IC1
4. Returns to "MONITOR
RAM
SP-1 002."
5.
Error is caused after
RAM
a long operation.
-9-
A15
\
A12
A4
\
A2
MZ-80K