Smith, T.L. Waldschmidt, G.J. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-WEPOB11 English 910-912 WEPOB11 ion linac cavity cathode photon Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-WEPOB11 https://jacow.org/napac2016/papers/wepob11.pdf A new S-band LCLS type Photo-cathode (PC) gun was recently installed in the APS linac. As a consequence, it was recognized that many of the linac accelerating structures were out of their 1mm straightness tolerances. In order to reduce the effects of wakefield on the beam, several of the misaligned structures were straightened. This paper discusses the bead-pull RF measurements, the effect of the straightening efforts on rf and the cell to cell retuning efforts that were performed.