Hantarex Polo 25" curvy corners

[solidhit]

Hi guys, I own a jamma cabinet that is equipped with a hantarex polo 25" monitor. Colors, brightness and constrast are perfect but I seem to experience a problem with the screen geometry. To be specific, the picture appears be very "curvy" on corners (all four corners). I can try to resize it, but the problem still remains. Anyone knows what could be the cause of this; Please, feel free to ask for any clarification.

[grantspain]

do you mean like an hour glass effect,if so it will be one of the east/west correction diodes leaky
a photo of the problem would help

[solidhit]

Look, I can't give you a picture for the time being, but...

Straight horizontal and vertical lines below are the screen frame.
The area inside the parenthesis is where the visible image is.
As you can see, the image near the top and bottom is pulled towards the center of the screen leaving a blank curvy area in all corners.
 
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[qrz]

posting a pic would help .
meanwhile, check for cold solder joints on L107,109
also check D135,C175,C183 and T117,118 ( for shorts/opens /value changes, etc.. )

qrz

[grantspain]

you have no pin cushion control,did this fault just happen or have you always had this
the reason i ask is because the only time i have seen this on a polo is when someone left off the east/west correction board

[solidhit]

Look, I don't know much about monitors, this cabinet was given to me by a friend.

I read your reply and googled the word pincushion over the internet. My problem is exactly what you mention, pincushion.

On my polo, there are two vertically placed mini-boards on the main-board. One holds some green colored basic controls like brightness, contrast, h-phase etc.  The other holds two green colored controls. I haven't dared to touch these two controls though. Should I;

As for the measurements, well to actually get these done, I would have to ask you questions like do they require discharging the monitor, should the monitor be on, how do you measure a capacitor, a transistor, a diode;

So, I really hope it is something that simply needs some adjustment somewhere.

[grantspain]

unfortunately monitors are not simple things to work on or repair for novices,mainly due to high risk of injury to yourself or the actual monitor
if you have no knowledge of monitors then even making the most basic of adjustments carry some risk
all i can do is advise you to wear some rubber gloves(like for washing dishes) if you make adjustments in the main chassis area
the adjustment you are looking for is the pincushion,it is one of two adjustment pots on the east/west correction board(the second of the vertical boards you mention)-the other adjustment is the keystone
try adjusting the pincushion first,if it makes no difference whatsoever then we are going towards more complicated fixes
you can try adjusting without power and if it makes a difference then come back to us for more advice

[solidhit]

I adjusted the pincushion control and I must say, the picture is a lot better.

I remembered something after making the adjustment. Back in the days of crt monitors, although the upper and lower borders of the screen were always straight, the left and right borders were a bit wavy (not much). The more I shrunk the picture increasing its distance from the left and right borders of the screen, the more straight that part of the border became.

Well, now I have the same thing here, a perfectly straight upper and lower border and a bit wavy left and right border. I don't suppose there is something I could try;

Thanks for the help anyway.

[grantspain]

sounds like maybe some caps are a bit leaky,could do a job lot and replace every electrolitic-its probably just a couple but tbh if you're gonna change 3 then why not change the lot and not worry about it for 10 years

there are a couple of small caps on the east/west board,maybe change them first