Hi, I am making a digital clock using HD74LS90P decade counters. For divide-by-6, I grounded R91 and R92, and shorted R01 and R02 with pins 8 and 9, which are the B and C of the output. The output goes to 5, and then starts oscillating between 4 and 5. It works fine when i set it to reset after 10. Does anybody know how to fix it?