Service manual

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may pick out the faulty component.
c)
Cause of Trouble
Faulty TMS 9929
Check Point
Check pins 3 to 10 and pins 25 to 32
Repair Method
1 If signal is absent replace TMS 9929 video
processor.
WARNING:When you earth the Video Rams - make sure you
earth them via a 10 OHM - 15 OHM Resistor. Do
not earth them directly as this may damage the
components.
SYMPTOM 4
When power is switched on: Very bad hum bars causing
corruption of display.
a)
Cause of Trouble
Faulty P.S.U.
Check Point
Check input voltage at J9. with Digital Volt
Meter.
Repair Method
1 Voltage should read between 23v and 24.5v - if
not change P.S.U.
MTX Service Manual