Help
I need a substitute of IC KA2143b or KA2143 Video Amplifier

ka2143b datasheet
http://rapidshare.com/files/95797372/datasheet.pdf.html

My Monitor service manual
http://www.free-service-manuals.com/Detailed/34404.html

well the problem of monitor is the screen of the monitor become smaller then it back to original size I already change the IC TDA9109 but there's no effect.
the Voltage of the monitor is change.

the monitor is new and the board is on good condition all component look good.
Around the board of ic 101 (KA2143b) where located on video board. something burned is happen around the IC the color of the board become dark brown.

The video amplifier will not change the picture size.

Does both the height and the width change or just one dimension only.

Rich B

Thank for posting rich;

TOP,BOTTOM,RIGHT and LEFT of the screen is change the size by atleast half inches then they back to the original size,. It changes very fast (to small screen change to original screen contenously change)

Your right rich but I can't find the deffected component of the monitor, as I know the video amplifier function is for the color. I already change the ic 302 TDA9109 sync ic and also check relay and change some mosfet component of it, also some change of high volt capacitor. it's the power supply or something is the problem?

thanks and more power

Rich is the visual animation description of the monitor error. it describe how the monitor change the screen size




thanks

Hi this sounds like EHT changing make sure EHT cap is fitted with metal to metal connecting properly.

This can also happen with monitors that have seperate EHT generation rather than the more common combined EHT and line scan, in this case the EHT regulation may be working in two modes due to a defective component. Does the size change happen quicker on way that the other i.e shrink quick and return large slowly or visa versa or does it just switch between the two.

Rich

Your right Rich the they change much faster than the graphical error description.
Sorry coz I'm novice, when you say (EHT) Extra High Hension capacitor, you mean the the biggest electrolytic capacitor on the power supply is defected?
Is theres other component I need to check?




thanks again and best wishes

No I mean the high voltage to the tube.

The reason I say this is that if the EHT to the CRT goes down the width & height increase and visa versa. If it was the power supply then usually upto a point the only the height changes.

RichB

Thanks for post again rich

The changing of the screen size is the same rate, a fast of millisecond.
so the size, height and the vertical cut by the CRT.
so the tube is still and good?, flyback focus and screen affect the tube performance, is the flyback is defective or the others component around to FTB? base on the service manual what component I need to check?
http://www.free-service-manuals.com/Detailed/34404.html

thanks for your patience

[IMG][/IMG]

it possible that affect the monitor performance?