Tuning a strat

Hello,
I have been playing acustic guitars for many years. I recently bought a new mexi strat which I am enjoying a lot. I use a small Crate amp and it sings. At some points on the fretboard it sounds out of tune. For instance, when the strings are it tune in the open position and I fret the A string on the third fret (for a C chord) that string is sharp. When playing a D chord the G string will be sharp. When I do barr chords at the third position the G and B strings will be sharp. Is this a problem with the guitar that can be adjusted? Is it my changing from acustic to electric that causes problems? Anybody have any suggestions.
Thanks

you need to check the set up as it sounds like your intonation is out.

Check this out:
http://www.guitartricks.com/lesson.php?input=8670

[font=trebuchet ms]A way to quickly check your intonation is to see if the harmonic at the twelfth fret matches the note on the same string fretted at the twelfth fret.[/font]

Thanks for the intonation lesson Dr. Simon. I played with the saddle adjustment and I am staying in tune much better now. I have always been shy about working on guitars, except for re-stringing, but electrics seem to be easier to make simple adjustments.
I have another problem. I can't get much volumn out of the high E string. No matter what the setting I get a thin, week sound from that string. Not much sustain. How can I make that thicker and fuller? I am using the factory single-coil pickups that came with my Strat.

Raise the treble side of your pickups... This puts the pole pieces closer to the strings for a stronger signal. To do this... simply give the screws on the treble side of the pickups about a half turn... then test to see if you like the results. If you go too far your signal will start to sound distorted... this is known as natural distortion. A half turn should be sufficient to get the boost that you need.

Or if your comfortable u can lower the string...but i suggest to do the above...

the problem could be that your pressing too hard on those strings when you fret the chords.

generally, acoustics require more strength to play than electrics, and when you first switch you need to adapt a far lighter and more controlled touch for playing on the electric.

when you next play the chord and it sounds out of tune, try relaxing the pressure of the finger on the offending string and see if it makes a difference.

Another thing to add to my previous post on this topic... I'm not positive of what kind of Strat you are playing... some Strats (especially Strat copies)come with pickups that aren't as sensitive. These pickups have a hard time picking up the higher frequencies of treble strings... If adjusting the height of the pickups doesn't fulfill your needs maybe look into getting some hotter pickups... (i.e. Texas Specials, Custom Shop '69s, SD hotrails...) Also check out the "Guitar Players Repair Guide" by Dan Erlewine... it's a great reference for anyone. It has info on stock Fender set-ups as well as set-ups of famous guitarists including Jeff Beck and Stevie Ray Vaughan. The set-ups include guides to pickup height... I think it would benefit you to check it out.

Much thanks to all for your imput. Raising the pickups made a marked difference in the volumn of the treble strings. My success with the intonation was not good. I finally took my Strat to a local guitar store guitar tech who knew exactly what to do. He put more springs under the tremelo mechanism and tightened the screws to the spring bracket. Now my tremelo bracket is tight to the guitar body. He installed 10 gauge strings (I had 9 gauge Fender Bullets). That was a major improvement as I am used to playing acustics. He adjusted the tension on the truss rod to compensate for the larger strings. He further adjusted the pickup height to get even volumn on all the strings. It seems to be in tune all the way up the neck and stays that way as I change chords. I am pleased with it and having a good time. It's time to rock. And all that for $30.

Originally Posted by: Franchesco... And all that for $30.

[font=trebuchet ms]There is satisfaction to be gained from doing it yourself, but the the main thing is to get your gear into proper working condition.

For most of us, the journey involves making music, not making gear capable of making music.

Enjoy![/font]