Is this set new to you? Have you ever seen it run right? Have you downloaded the TM's, and maybe looked at them? Can you work with schematics? If you look next to most components, there should be printed the component ID, like S1, or FU1. Have you started with the troubleshooting diagram, in the -12 TM first?
The three places you measured on J1 are meaningless for starting purposes. When the set will not start at S1, and will turn over at S10, you need to start troubleshooting at S1. If you look at the schematic, you will find the S1 circuit schedule. The schedule tells you what contacts should be made when the S1 is in each position. Look at the start position. When the S1 is in the Start position, you should have 24 volts at the common pins, (pins 2,4,6,8 ) and most importantly, pins 3 and 7. Pin 3 is for all the circuits needed to RUN the set. Pin 7 is the one to START the set. So, after following the proper set up procedure in the -12 manual, place the S1 in the start position and see what your voltage is at pins 3 & 7 is.