Hi Phil,

it seems, you are not familiar with LEDs.
In opposition to lamps, they need a resistor in series in any case !

Otherwise they are killed. And if only 1 LED works, the others seems already killed. A good resistor value at 5V was about 1kOhm but not below 220 Ohms.
Also they work like Diodes only at 1 polarity.

Also drive the LED (always with resistor) from the output pin against VCC. Since only the low output current of the 8051 was high enough to drive a LED.


Peter