Dell 1626ht strange vertical wobble.

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I have a 6/7 year old Dell 1626ht 21" sony trinitron tube monitor.
After a recent move up the road it has developed a strange wobble that
occurs normally after a few hours use, stays for a few hours then goes
away sometimes.

It is really hard to describe. It only effects the vertical.
The best I can say is that the inner portion of the screen "pinches"
towards the middle, but only in the vertical.
The top and bottom of the screen remain more or less in the same
position (slight movement) The center of the screen remains in the
same place, but the 25% and 75% position seem to move towards 35% and
65% respectivly. ie. it goes from linear to non-linear.

It has a period of maybe a 1/10th of a second, but is fairly random
maybe 2 or 3 times a second.

I've tried degaussing, checking/swapping cables, using a different PC
to drive it and changing the power cables. Oh and I've thumped it too.

I assume it is a dry joint or crack or similar.
Could it be dust that has moved during the move?
It doesn't make any odd noises or smells.

It's a great monitor that I have enjoyed for many years. Infact I
moved it with me from the UK to Spain 3 years back with no problems.
Any help would be most appreciated.

Thanks

Matt Casey

 

[Wayne]

I have a 6/7 year old Dell 1626ht 21" sony trinitron tube monitor.
After a recent move up the road it has developed a strange wobble that
occurs normally after a few hours use, stays for a few hours then goes
away sometimes.

It is really hard to describe. It only effects the vertical.
The best I can say is that the inner portion of the screen "pinches"
towards the middle, but only in the vertical.
The top and bottom of the screen remain more or less in the same
position (slight movement) The center of the screen remains in the
same place, but the 25% and 75% position seem to move towards 35% and
65% respectivly. ie. it goes from linear to non-linear.

It has a period of maybe a 1/10th of a second, but is fairly random
maybe 2 or 3 times a second.

I've tried degaussing, checking/swapping cables, using a different PC
to drive it and changing the power cables. Oh and I've thumped it too.

I assume it is a dry joint or crack or similar.
Could it be dust that has moved during the move?
It doesn't make any odd noises or smells.

It's a great monitor that I have enjoyed for many years. Infact I
moved it with me from the UK to Spain 3 years back with no problems.
Any help would be most appreciated.

Thanks

Matt Casey

Hi, this is a Sony N3 chassis, and far and away the most common fault
is a failing/failed IC007 CXA2043Q, which results in many
deflection-related problems.

Wayne

 

[Catmacey]

Cheers Wayne,

I think I might have a go at replacing that IC.
Any ideas about where to source the schematics for this chassis?
I'll google for the IC. )

Matt.

 

[Wayne]

Download from Sony section here
http://www.geocities.com/monitorss/schematics.html

Wayne

 

[Catmacey]

Excellent.

FYI I got a CXA2043Q from www.bluestar-online.com $32 which I thought
wasn't too bad. At that price I thought I may as well get one and see
what happens when I swap it out.

Even if it doesn't work I'm still in no worse a position. Well apart
from having spent $32 for now reason.

Thanks!

 

[Yukio]

Sounds like a stray External Electromagnetic Field to me !!!
Reasoning Vertical sweep is usually USUALLY very close to 30 CPS and the
interfering field is due to some device powered from the 60 cycle
powerline. EG. some fan motor usually within a few feet from the Monitor.

I once trouble-shot a MAC that had a jigglely display , Turned out to be a
BlowerMotor in the NEXT room about 6 feet away from the back of the monitor.
Had a devil of a time locating it because it was in the next room, but I
knew what I was looking for, so it came as no real surprise. Next step
would have been to look upstairs and downstairs !

To observe this effect, operate a Fan or device that uses a shaded pole
motor near the back of an operating monitor and see the display shimmy or
wobble in the Vertical plane. If the monitor was running at exactly the line
frequency the image interference would be visible but stationary. At any
other frequency the interference will crawl up or down the screen .

Yukio