Mitsubishi Megaview XC-3315C weird lines at top of the screen - how can I fix?

[eastbayarb]

My monitor has these wierd white lines on the top of the screen.

Picture 1 (dreamcast at 31khz via VGA) shows white lines at the top of the screen above the white border.

Picture 2 (dreamcast at 15khz via 3rd party hacked VGA cable) shows even worse white lines at the top of the screen above the white border.


is there any way to fix this? Monitor is otherwise really good.

[northerngames]

mine was the same at first but it was on a nanao running vgabox mod 15K and there was not as many lines as yours but there were 5-6 lines like yours at first.

 I adjusted the V-hold and got it down to one small straight line across the very top border.

[qrz]

looks like vert retrace..
so, very likely a failing "pump up" cap in the vert output .  typically 100uF @35v 

there is usually a diode (cathode side) connected to the pos side of the cap . cap neg to output ic .
anode of diode to "pump up " on vert ic.

note: the diode can also fail ....
  there will be a higher positive voltage on the cathode when the circuit is operating properly.

qrz

[eastbayarb]

looks like vert retrace..
so, very likely a failing "pump up" cap in the vert output .  typically 100uF @35v 

there is usually a diode (cathode side) connected to the pos side of the cap . cap neg to output ic .
anode of diode to "pump up " on vert ic.

note: the diode can also fail ....
  there will be a higher positive voltage on the cathode when the circuit is operating properly.

qrz

[/quote

qrz,

is this information directly related to my particular monitor? If so, perhaps you have some info on how/where to replace the diode(s) ?

[eastbayarb]

mine was the same at first but it was on a nanao running vgabox mod 15K and there was not as many lines as yours but there were 5-6 lines like yours at first.

 I adjusted the V-hold and got it down to one small straight line across the very top border.

pardon my ignorance, but either I am totally blind, or the V-hold adjustment knob (or whatever adjusts it) is just not on the monitor? Is it inside ? If so, where?

thanks

[qrz]

adjusting the vert hold merely changes the vert frequency . a dirty pot  or slight misadjustment can put the operating freq just outside the lock range of the vert osc.....

most vert output stages will have the diode /cap combination , be it a TV or monitor. i have no print , thus unable to provide specific location id....sry.   
the diode can be a gen purpose 1A 100PIV or better. replace cap with same type/rating as in circuit

will search for print and advise........

qrz

[eastbayarb]

Anyone know why when I have my Neo Geo hooked up to this monitor (after adjusting the vertical/horizontal position and size) that it looks fine, but when I put in a different game into the system, the changes I made to the horizontal/vertical position and size are not the same for the previous game cart? It's like the monitor is reverting back to factory settings or something.

[qrz]

possibly reverting to default settings .
but,  would be more inclined to think slight signal differences
between game systems to be more likely .


qrz

[northerngames]

are they all the same res setting for each of the game's that differ?