Not sure what you have there, but first thing I check is the secondary side rectifiers for shorts.
Remember this is an SMPS - switchmode power supply - and it does not run at 50/60Hz. SO any "AC" over there will not register on your meter well.
Note pin 4 of the IC is the feedback from the secondary, and it can shut things down. Make sure we are not in shutdown.
Note the primary and secondary sides have different grounds. SO you can't use the same ground as a reference to take readings on both sides. I suspect the you were using the primary side ground - where you got the 13v DC - to read the secondary voltages. That would explain the extra 100v everywhere.