1)running at 4.8V should be ok, but what if your voltmeter is 10mV off? Get it to 5V!
2) what is !EA tied to?
reset the device with a high, the oscillator runs for about a second and then goes to ground.
3) did you check that the reset polarity is the same for both chips (for some it is !reset, for some it is reset)

Erik