SN74LS245N outputs 1 Volt when OE is high, 0 Volts when OE is low
When you see an "inbetween" voltage on a digital bus (i.e. not logic "0" and not logic "1"), the cause 99.7% of the time will be bus contention.  i.e. you've got two outputs connected together, one is pushing a "high", the other a "low".  And you end up somewhere inbetween.

Besides double-checking ALL your wiring, suggest you check the "DIR" signal, make sure that's really logic HIGH.  If it's logic low, then you'll be driving the LED's with the '245' and the '173's at the same time.  

Did you build this on a plugboard?  They're notoriously finicky.  Wiggle wires.