2 issues - ghost images and vertical collapse

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supertakumar
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2 issues - ghost images and vertical collapse

Post by supertakumar »

Hi i have a couple of problems with two different monitors.

The first one is what appears to be ghost images or outlines.

The second is what might be a vertical collapse (according to a tech chap who saw it). Could anyone confirm?

Any ideas where to start with these guys? I have a couple of technicians coming to help me at the weekend, so any advice would be a big help.
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RMRM
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Re: 2 issues - ghost images and vertical collapse

Post by RMRM »

Regarding the Vertical collapse, you should check the HOT (horizontal output transistor), it might be shorted or if you're lucky it's just a cold joint problem.

Dessolder it and check it out with a multimeter out of the circuit.

Can't help you with the other problem :(
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mastercello
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Re: 2 issues - ghost images and vertical collapse

Post by mastercello »

Second one is a NAC, right?

Is the small remote pcb with the Potentiometers to adjust the picture connected?
I remember someone else had this problem in the past.
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supertakumar
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Re: 2 issues - ghost images and vertical collapse

Post by supertakumar »

Thanks guys.

Yeah it's a NAC.

I'll check the HOT and the pot board tomorrow and let you know what i find.
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Asayuki
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Re: 2 issues - ghost images and vertical collapse

Post by Asayuki »

RMRM wrote:Regarding the Vertical collapse, you should check the HOT (horizontal output transistor), it might be shorted or if you're lucky it's just a cold joint problem.
Never seen the chassis in question, but i have also never seen a vertical defect coming from the horizontal section...
The HOT makes it possible for the LOPT to generate the anodic voltage for the tube. Without it the tube wouldn't light up and he wouldn't see the horizontal line. Horizontal deflection is obviously working there.
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RMRM
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Re: 2 issues - ghost images and vertical collapse

Post by RMRM »

Asayuki wrote:
RMRM wrote:Regarding the Vertical collapse, you should check the HOT (horizontal output transistor), it might be shorted or if you're lucky it's just a cold joint problem.
Never seen the chassis in question, but i have also never seen a vertical defect coming from the horizontal section...
The HOT makes it possible for the LOPT to generate the anodic voltage for the tube. Without it the tube wouldn't light up and he wouldn't see the horizontal line. Horizontal deflection is obviously working there.
I had the exact same problem with a chassis before, and it was a HOT problem. I might be mistaken though, maybe grantspain can clear things up when he sees this thread :awe:
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grantspain
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Re: 2 issues - ghost images and vertical collapse

Post by grantspain »

hot on some monitors causes horizontal collapse but on most will cause chassis into ocp
that is a vertical collapse,caused by a number of things,vertical winding of deflection coil not connected to chassis correctly or open circuit,vertical deflection ic or circuit faulty,vcc to deflection ic missing,broken vertical size pot

depends on monitor model

first picture looks like poor quality vga cable
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supertakumar
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Re: 2 issues - ghost images and vertical collapse

Post by supertakumar »

Thank you for the help, really appreciate it.

I will try and get some more photos of the monitor so it's possible to identify the model and see if there are any immediate visual cues as to what the problem might be.

Thanks again
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