Upon opening the cover I went directly to the degaussing circuit. The reason for that was the display had bad colors (color impurity). But to my surprise, it was ok. All the voltages in the primary and the secondary section of the power supply checked fine. The voltages at the HOT was also fine. I looked at the screen neck and the CRT board and all checked fine except, the filament were not as bright as it should be.

To myself, I started thinking of a bad CRT tube but did not give up. So I started working on the computer monitor from a different point of view. Since there are bad fonts (characters) on the screen and the display is not that clear to read, there must be something that has to do with OSD (On Screen Display) which have to do with the screen display. There was an IC (201) on the CRT board that has the label LM1237BDCE/NA. I checked that IC in my data book and found out that this IC has to do with computer monitor display.

I soldered the IC out. With the multi meter set on the Diode range, I started to compare the readings with the new IC and sure enough, although it was the same exact IC but the reading was different which gave me the indication that the IC I took out was bad. I put in the new IC and soldered the legs and fired up the computer monitor and everything came back normal. The colors restored, and the letters characters were fine and easy to read.

I almost gave up on this computer monitor thinking the problem was a bad CRT tube but reality showed that it was not. It was a good challenge and really glad it got fixed.


10 years of practical electronics. owner and operator. I service the Bethlehem area in Palestine. I repair Xbox 360 and all play stations and modify their power supplies. also repair lcd and Plasma tv sets, and lcd computer monitors. I have a degree from Bob Jones University in general business and one year degree in Industrial electronics. a intensive course in Media. I also work as a camera and audio man as a free lancer. Also great experience in video editing and installing surround systems for home and movie theaters.

One comment on “Dim Display With Color Out In Mag CRT Monitor Model# 786N

  1. Daud Asi says:

    Very wel done

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