Sharp MZ-80B - Page 15

• Memory/Reset Circuit Block
AO - A13
Data selector
RAM block
Problem
Picture "panic" when
power is on.
Abnormal action
immediately after end
of program due to
BOOT program
Error when program
is in RAM
AO-- A10
ROM block
Memory/Reset Circuit
Memory control
circuit
07
DO
,Check Point
CPU
control bus
A15
1
Al2
Does pin 26 of I C3 go from High to Low when the BOOT
reset SW is pushed?
No: Check IC33
Yes: Proceed the following.
Is pin 15 of IC2 High?
No: Check IC34
Yes: Check address line AO - A15 (ICB, IC10)
Data line DO - 07 (ICll)
Control line (lC7)
IC2, ICS, IC14, IC1B
Is pin 15 of IC2 at Low Level?
Yes: Check
IC34
No: Check IC2
Check RAM
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