Memotech Limited MTX 500, Service Manual

Page: 45 / 78

41
4 Check links 6 and 7 on MTX.
5 Look closely at the 273 (5A) on mother board
and associated circuitry.
c)
Cause of Trouble
RS232
Check Points
As above.
Repair Methods
As above ->
1 If intermittent fire up modify timing chain ->
see page 46.
d)
Cause of Trouble
Printer
Check Point
J6 Printer o/p
Repair Method
1 Be sure that the fault is not the printer
itself or the interface cable.
2 STROBE should be Hi.
3 Check Printer data lines (PRD0-PRD7) on 74LS
374 and on J6.
4 Also check pins 11, 13, 15 and 17 of 1D the
74LS244.
5 Less likely-check the 74LS74 for STROBE.
MTX Service Manual