Cordless Phone Repair
Cordless phones fall into the same category as VCRs, DVD players, CD players, small TVs, etc., in that they were made to replace, not repair. Short of replacing the battery, which is not likely the culprit, you can't do much with them. I have yet to find any kind of source for schematics, whether the phone is Cobra, BellSouth, AT&T or whatever. If the phone is older (I'm not familiar with your model), look at this as an opportunity to upgrade. However, if I were you, I'd stick with a 900MHz digital spread spectrum phone and stay away from the 2.4GHz models. My experience is that the 2.4GHz phones have lousy range -- 100 ft. vs my being able to use my 900MHz phone anywhere on our 10 acres.
Dean