Contrast Problem In Monitor

If you ever come across contrast problem in CRT monitor, go straight to the video pre amplifier IC in the CRT board. Usually it is the biggest IC in the CRT board and some typical part numbers are LM1203N, LM1281N, LM1269NA, LM1236, LM1237N and etc. Get the specification from the internet and look for the pin that have the name “ABL” or “Contrast”. Trace from there and eventually you will reach the abl pin of the flyback. Replace the video pre amp IC or check all components in this ABL (automatic blanking limiter) line if you can’t control the contrast, no contrast or even dim display. In Acer CRT monitor, a corrupted eeprom data may also caused the display to become dim and the contrast can’t go maximum. Reprogram the eeprom and you will get back the contrast>