Finished the SEX and went to measuring resistances. Everything fine until I got to the terminal strip with all the diodes attached. C1, C2, and C5 are all at 0 ohms but C4 was around 500 ohms. I examined all the diode directions and connections in general and could not find a flaw. so I re-soldered the connections around C4 and C5 and the power transformer (hoping to rectify a cold solder joint). Interestingly the resistance seemed to go down (measured around 200 ohms) but now it seems to be back at the original. Any thoughts, suggestions on tracking this down further would be appreciated.