The lamp doesn't light up nor flash on incoming calls on any of the 4 CO lines, but the common bell wiring provides ringing on each of the 4 lines as normal. Once I depress the line button, the lamp lights up. If I put the call on hold, the lamp winks normally. This is the same for all 4 lines.

Have not changed dial tone provider nor line cards. Ground has not changed.

I will check all the fuses and the interrupter when I'm back home; however, I checked this morning early and the fuses on the 620A are all depressed as they should be -- in other words, none is popped out. I didn't check the power supply fuses.

Basically, the lamp doesn't flash nor light up continuously on the incoming call but does operate normally after the call is answered and if put on hold.

Bill