If your parts are General Semi diodes you should be able to figure out what they are from there, based on what kind of package they are in. (SMA, D-Pak, etc.)
KT3 is a BAS21 diode. Link goes to the data sheet, includes information on similar diodes (BAS19/BAS20/BAS21) and the date code (yours seems to be July 2007)
CVL seems to be a transient voltage suppressor. The link goes to a site with lots of SMD codes.
A48 could be one of several things. You'll need to compare the connections of your chip to the datasheets of the various parts that may be marked A48 (most likely a voltage regulator.)
For the 1PX, the dot shows pin 1. Putting Pin1 at the lower left mean you read it 1PX instead of other combinations you tried (K and stuff.)
Sorry, I can't give you any really good tips for finding the codes.
The linked site helps, and there are others like it, but it all comes down to having good google-fu.
Google, get ideas, check the circuit against the datasheets.
Best Answer
Taiwan Semiconductor makes a 1N4448 diode in a SOD-323F package with 'S2' marking.
Some accurate measurements on the package would help to confirm.