Why are two LEDs on? is 7489 broken?
This is a memory IC, so it remembers the state of D1-D4 when ME is low and you pulse WE low. The leds that should be OFF are R1, R2, and R3. R4 should be ON. To change which LED's are ON you need to change the state of the memory inputs (D1-D4), then bring WE low then high again and see the change. The data outputs of this IC are inverted, so to turn an LED 'ON' you need to connect the corresponding input to V+. Your only using address '0' (A0 - A3 are low), so toggling the ME pin has no effect. If it is high (V+), it will disable any changes to the memory, but not affect existing memory and the outputs.The pdf sheet on this part specifies a load of -12mA as being a safe maximum load, as a current sink. At 330 ohm's the LED current is only 6mA. If the IC's output is irrational then it is oscillating or it is blown. Add a .1uF capacitor to the power pins and a 10K pull-up resistor to the WE pin for stability.If you turn off the power this memory will forget its contents and all LED's should be OFF.