I wrote a simple test program for my 89C52:

$MOD52
mov P1,#055H
do_nothing:
nop
ajmp do_nothing

The circuit is simple with EA connected to 5V and RST pin to TL7705 supervisor chip.
This doesn't work. I've tried with RC reset circuit and it also doesn't work.
But it works if I connect 100pF capacitor from RST to 5V and then switch on AC power supply, switch it off for 8 seconds and then switch on again!
What's wrong?