I have 6 PS14s that are rated at 14vdc, 300ma each. I would like to do away with all of them and power my Digitrax boards with my Astron 20a 13.8vdc power supply. Would there be any issues with doing that?
Shouldn't be a problem. 6 x 300mA is 1.8A, well within your 20A power supply. 13.8vdc is close enough.
I'm not familiar with what you are powering but one thing to keep in mind is the amperage aspect of using the larger power supply. The PS14s are rated at 300 ma. 300 ma with a short circuit situation isn't much but with 20 amps available to run through a short circuit if you get one you might expect to see smoke. You might want some type of circuit protection between the power supply and the individual boards. Sumner
RS-35a or m? Beast! Have one, but I use switchers for most everything these days since that linear supply is so big and heavy. Drop a 3 amp fuse inline with the power feed. I use the cheap 5 amp switchers from Amazon (again, fused) for the layout, the 3 amp versions are about $14 plus the price of a power cord if you can't scrounge one.
This! Not only the boards need protecting (they may have been designed to depend upon their standard power supply to cut out above ~300 mA), but power supply wiring, connectors, all of it needs adequate ampacity or over-current protection. 20 Amps needs 14 AWG wires to handle maximum current, with connectors to match, or upstream overcurrent protection (e.g. in-line fuseholders). The wiring from the power supply to the overcurrent protection must be capable of handling the power supply's trip amperage, or provide inline over-current protection upstream of that wiring.