Red colour missing
- A bended color pin at the VGA connector. (If pin one is bend then there would be no red color)
- A defective VGA signal cable. If the internal wires were broken then there would be missing colors. You can check if the signal cable is good or bad by doing a continuity test using a multimeter.
- Dry joints in the CRT board such as in the CRT socket pins, video pre amp and driver IC and even at the connector pins. In fact this problem contributed about 80% of Monitor color problems. Applying fresh solder would usually solve the color problem.
- A defective IC either in the Video Pre-amp or Video Driver IC.
- Faulty components in the CRT board. It could be a shorted driver transistor or even electrolytic capacitors that the ESR reading had shot up!
- A bad CRT socket. Sometimes decayed glue could cause the internal pins rusted and thus affecting the colors. Replacing only the CRT socket would definitely solve the problem.
- A weak or a defective picture tube (CRT tube). Yes, I do came across one of the electron gun (most probably the cathode materials had used up) in the tube faulty caused a missing color in the screen. There’s no way to repair this type of problem-the only way is to replace the CRT tube.
- In the newer type of Monitor, color setting is save in the EEPROM IC . Thus, if the EEprom data is corrupted, you would also get a missing color! The only way to repair it is to reprogram the IC or use a soft jig to tune it back the color setting.
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Dec 05, 2007 |
Compaq P110 21" CRT Monitor