Simplex 4006 Issues

There’s nothing better than coming home after a long day at work and seeing that you got a new panel waiting for you on your doorstep.

You clean it, wire it, and plug it in, only to find out that it doesn’t work. What’s up with that?

I got a Simplex 4006 in the mail today. When it gets power, the screen turns green, two LEDs in the back turn on (LED 1 and 2) and nothing else happens.

No other LEDs turn on. (Not even AC Power!)

The manuals have proved no help, as it’s really just copy and pasted for both the 4006 and the 4008. And then it’s only the basics.

Any help would be appreciated, as I’ve had so much luck with so many other panels, how could this one fail me?

All in good spirit,


I only worked on one 4006 and that was to set up monitoring. I don’t have any information beyond what is in the published manuals.

LED 1 and 2 are in the NAC monitor circuits to indicate trouble.

There is a very slim chance that the RAM battery is half dead and has the memory in a state that is blocking the processor from starting. That battery is on the main board so the display assembly has to be removed to get to it. Take the battery out and check it. You can reassemble the system without the battery. Wait at least 10 minutes with the battery out for the RAM to completely clear in case there is a capacitor in the circuit. Then power up and hope for the best.

I tried what you had suggested and it’s still a dud.

I found a new front keypad annunciator display for it, with new ribbon cable and all, since I’ve had to replace the screen for a 4010 before (the 4010 had shown the bad LCD crash code, which was resolved with the change) and still no luck.

By this point, I believe that the whole panel is probably bad and will more than likely junk it for a different one.

Thanks for your help!