MVS monitor help needed ***Updated w/ Pics***

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Neo Ash

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I’m having a little trouble with the monitor in my 4-slot ver3 big red. The monitor looks good until all black is displayed on the screen. When a black/dark background is on the screen, I notice a few horizontal lines across the monitor…the lines are on slight angel. It’s not screen burn in. When I make adjustments to the monitor these lines change in location. It doesn’t matter which slot I switch to either. Am I missing another adjustment that is located deeper in the cab or on the back? Could it be the power supply? I know that the power outlet is grounded. I’m pretty sure the fan in the power supply is not working…can’t feel any air coming out. I’m guessing it’s the original power supply.
 
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Lashujin

Lashujin

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Could be master brightness is set off. Check the dial on the flyback tx, but be careful monitor voltages can kill

I had a monitor that would get lines like that if the master brightness was set up too high
 
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Neo Ash

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Lashujin said:
Could be master birghtness is set off. Check the dial on the flyback tx, but be careful monitor voltages can kill
Click to expand...

Would this be behind the back panel? How would this be marked?
 
Lashujin

Lashujin

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I wasn't marked at all on mine.

Follow the red wire coming out of the suction cup on the back of the monitor. It should go into a largish piece on the monitor pcb. There should be two (unmarked on mine) dials on there. These dials are master brightness and Focus.

On my machine the dials were difficult to reach and you couldn't see them because they were on the other side of the thing. I used a mirror.

Watch though, even when off the monitor carries lethal amounts of power.
 
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SuperGunGuru

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It does sound like your monitor's brightness might be set too high. Doesn't the remote adjustment board for the monitor have a brightness pot on it? If not, the adjustment would be made on the flyback transformer. If you look at the suction cup device attahced to the tube and follow it back to where it goes, that's your flyback transformer. There should be 2 knobs on it. One adjust the screen brightness and the other controls focus. Make sure to BE CAREFUL when adjust that stuff. I sometimes use a screwdriver when I have to adjust the controls right on the flyback.
 
ttooddddyy

ttooddddyy

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The screen voltage adjustment is always the bottom pot (below the focus pot) on the flyback transformer.

Turn just a few deg anti clock and the retrace lines should disapear.
 
chris1

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If you want to replace the fan or power supply itself....The fan could be bought at Radio Shack or online sites..(matching it up).

As I don't know what effect a dead fan could have on the power supply..Could a jammed,humming fan cause such an interference.(?)

A direct replacement can be bought at Happs..and or other places as I thing Betsons might have it.

http://www.happcontrols.com/powersupplies/80007200.htm

80007200.gif


Direct Replacement is the one with External On/Off Cable.
 
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Neo Ash

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I just took a picture of the main monitor adjustment board.
DSC00897.jpg


Does anyone have pictures; or could take pictures of what I'd need to adjust on the back of the monitor. I don't want to screw anything up.
 
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Neo Ash

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chris1 said:
If you want to replace the fan or power supply itself....The fan could be bought at Radio Shack or online sites..(matching it up).

As I don't know what effect a dead fan could have on the power supply..Could a jammed,humming fan cause such an interference.(?)

A direct replacement can be bought at Happs..and or other places as I thing Betsons might have it.

http://www.happcontrols.com/powersupplies/80007200.htm

80007200.gif


Direct Replacement is the one with External On/Off Cable.
Click to expand...

Would it be a good idea to replace the power supply anyway?
 
Lashujin

Lashujin

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Neo Ash said:
Does anyone have pictures; or could take pictures of what I'd need to adjust on the back of the monitor. I don't want to screw anything up.[/B]
Click to expand...

That's something else. What you want to look for is the master brightness on the flyback transformer. As said before, follow the (usually Red) wire out of the suction cup on the back of the monitor, the housing it goes into is the transformer, on there will be the brightness dial.
 
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Neo Ash

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Thanks guys.

Should I attempt to make these sorta adjustments while the monitor is on; or would it be safer (for me and the cab) to power it off while making this adjustments?
 
ttooddddyy

ttooddddyy

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The adjustment is the one below the focus pot (the lower pot on the lfbt)

B1000462410.jpg


To be on the safe side switch off the cab then back the screen pot off (anti clockwise) just a whisker, just a few degrees. Then check the picture, if you still see the retrace lines repeat untill they are gone.
 
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Neo Ash

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ttooddddyy said:
Whats wrong with the existing supply ??
Click to expand...
The fan is frozen almost solid. I was thinking the jammed fan could be cause some sort of hum that might cause interference with the monitor.

Is heat an issue???
 
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Neo Ash

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Thanks guys!!! I made an adjustment to the brightness dial; the monitor looks fine now. A few more tweaks on the main adjustment board and it will be perfect. :multi_co:
 
chris1

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ttooddddyy said:
The screen voltage adjustment is always the bottom pot (below the focus pot) on the flyback transformer.

Turn just a few deg anti clock and the retrace lines should disapear.
Click to expand...




Thank YOU!!!

I just used this thread to fix the lines(retrace lines) in my 2 slots monitor..:buttrock:
 
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