I have problems with texturing the grey part of the calculator I have been working on recently. If I try to texture the same part of the model with an other picture it works perfectly well.
the .blend file will be nice to check the things out but when looking on the pictures I decided to try to answer You because I could NOT comment (newbie here).
At least You are using two different textures and probably also the materials for Your model so keep in mind that if U using more than one for one UV mesh U have to ASSIGN the desired material with the desired faces!
On the image below there could be seen top face assigned to the BLUE material and the rest to the RED material. So if U have some faces assigned to the material which works and not the crucial ones to the material with that "texas instruments" texture it could be a problem.
...if this is not that case then please try to provide us Your .blend file here so we all could check it and write You a solution buddy.