Memotech Limited MTX 500, Service Manual

Page: 3 / 78

CONTENTS
Page
Overall Description ...................................1
Internal Expansions compatibility .....................4
Z80 CPU ...............................................6
Z80 Pin Description .................................7
Z80 CTC ..............................................10
Z80 CTC Pin Description ............................11
Z80 DART .............................................13
Z80 DART Pin Description ...........................14
TMS 9929 VDP .........................................17
PAL VDP Horizontal Timing ..........................18
9929 Signal Waveforms ..............................19
MTX Series System Bus ................................20
System Block Diagram ...............................21
MTX Disassembly Instructions .........................22
Trouble Shooting Guide ...............................25
Symptom 1
No Display/Black and white display............26
Symptom 2
Blank screen/no humming/power on..............28
Symptom 3
Corrupt Video Display or characters...........30
Symptom 4
Bad hum bars..................................31
Symptom 5
Green screen and hum..........................32
Symptom 6
Load and save problems........................35
Symptom 7
Sound problems................................37
Symptom 8
Keyboard......................................38
Symptom 9
Memory Exps, ROM Exps, RS232, Printer.........40
UM1286 Modulator .....................................42
Testing and Setting up ........................43
Mother board Links and PAL Colour coding .............44
PROM Codes for memory expansion boards ...............45
MTX Service Manual