Problem MTC9300 20" wierd lines on top - Vertical linerity issue??
- Thread starter Georgian2
- Start date
Retroman839
Senior Member
I’m no expert on the issue but
Does the middle wave look like the waveform for a bad leaky diode ?
The Diode might read ok out of circuit,
but in circuit Under a higher voltage load than your diode it’s failing.( leaking )
Top vid - component shorting to ground ?
Does the middle wave look like the waveform for a bad leaky diode ?
The Diode might read ok out of circuit,
but in circuit Under a higher voltage load than your diode it’s failing.( leaking )
Top vid - component shorting to ground ?
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I changed the folowing parts with no difference at all
D132,128,129,130,131
C142
L105
TH103 (HR7389 the closest spare flyback I have).
5V adjust potentiometer out and pads shorted for maximum (5.5V)
Some other capacitors.
(red and blue are swapped because is an old mtc9000 cable thats why the funny colors))
Second image is without video signal and flyback turned up.
I doubt that this chassis has ever worked, could be some customer return, a production error, f*** knows.
D132,128,129,130,131
C142
L105
TH103 (HR7389 the closest spare flyback I have).
5V adjust potentiometer out and pads shorted for maximum (5.5V)
Some other capacitors.
(red and blue are swapped because is an old mtc9000 cable thats why the funny colors))
Second image is without video signal and flyback turned up.
I doubt that this chassis has ever worked, could be some customer return, a production error, f*** knows.
Last edited:
Retroman839
Senior Member
And the tube is fine with other chassis you say ?
It really looked to be in the retrace lines
In the other video ..
ripple from bad caps or power supply ?
Turn brightness right up so retrace lines are very visable just so you can see they are positioned ok in case they have moved ?
Because of the symmetry of those lines it seems to be electro magnetic
Interference causing the wave like shapes .
. Something Out in the deflection circuit ?
Is the hot on it’s way out ? Just slowly collapsing
It really looked to be in the retrace lines
In the other video ..
ripple from bad caps or power supply ?
Turn brightness right up so retrace lines are very visable just so you can see they are positioned ok in case they have moved ?
Because of the symmetry of those lines it seems to be electro magnetic
Interference causing the wave like shapes .
. Something Out in the deflection circuit ?
Is the hot on it’s way out ? Just slowly collapsing
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As one can see in my last post second image, the screen is all they way up. the retrace lines are not in place, somehow all of them are dim and on the upper side. Lifting R38 on the neck board (disable the G1) brings all the retrace lines in place and with the right distace between them.
