Allen Bradley SLC 500 question

[Jim Maty 0]

Hello, I recently acquired 2 used Allen-Bradley SLC 500 racks. One rack includes the power supply, a CPU and input and output modules. The other rack includes a power supply and input and output modules, no CPU. The racks are connected with a multipin connector/cable at the right of the CPU rack and the left of the slave rack. When I put 110VAC power to both power supplies, either of the power supplies turn on. The fuses in both power supplies check ok. When I disconnect the comm cable between the 2 racks, the computers still do not power up. Can you offer some suggestions on how to get the computers to power up.

[Mickey 71]

Which power supply do you have ? (see PDF below) Check your power supply's jumpers if it has them. (see PDF below) powersupply.pdf jumpers.pdf

[Jim Maty 0]

The jumpers are on the center and the right pin, 110VAC. The Cat #s are 1746-P1 .

[Ken Roach 194]

The chassis interconnect cable is purely for the data bus; it doesn't carry power. I am very surprised at the behavior you describe. If anything, the power supplies should turn on individually. The 1746-P1 is the smallest power supply in the family; depending on the number of slots and the mix of modules you might be overloading it. It responds to overload by simply shutting down the +24 and +5 VDC side and turning off the LED. You can apply main power to a 1746 series power supply without the chassis attached and see if the power LED comes on; that would eliminate the rack or any of the modules as the source of the problem.

[sammy 3]

I thought that the SLC 500s only had processors and the computer was the piece of equipment you programmed the processors in the SLCs with. Am I wrong?